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Pathology - Thalassemias
Definition • A collection of hereditary erythrocyte diseases resulting from the insufficient synthesis of alpha or beta globin chains. Pathogenesis • Insufficient production of either A- or B-globin chains results in the accumulation of surplus unpaired chains. • This culminates in the destruction of developing erythrocytes and the premature elimination of circulating erythrocytes in the spleen. The anemia in thalassaemia results from a combination of inadequate erythropoiesis and splenic haemolysis. Beta-thalassemia major • Resulting from mutations in both B-globin genes.
• Complications arise within the initial months of life as HbF levels diminish and surplus A-chains start to build in erythrocytes. • Deteriorating anaemia results in heightened erythropoietic stimulation, causing an increase in the bone marrow volume and the reactivation of extramedullary haematopoiesis.
• Manifestations in infancy include pallor, inadequate feeding, and growth failure. • The complete blood count indicates hypochromic, microcytic anemia. • The diagnosis is corroborated by the nearly absent HbA on hemoglobin electrophoresis. Beta-thalassemia minor • Resulting from mutations in a single B-globin gene.
• Asymptomatic silent carriers exhibit moderate microcytic anemia. • An elevated HbA2 level on hemoglobin electrophoresis is a critical diagnostic indicator. Alpha-thalassemia • A-chains are essential for both adult and fetal hemoglobin. • In the fetus, surplus G-chains aggregate to form tetramers referred to as Hb Bart's. In adulthood, surplus B-chains aggregate to form tetramers referred to as HbH. The deletion of all four A-globin genes results in severe fetal anemia, widespread edema, major hepatosplenomegaly, and fetal demise between 28 and 40 weeks of gestation. The deletion of three alpha-globin genes results in HbH illness, characterized by varying degrees of persistent hemolysis. The majority of individuals experience moderate chronic hemolytic anemia throughout their lives (Hb 7–10 g/dL) accompanied by splenomegaly. Deletion of one or two alpha-globin genes results in alpha-thalassemia minor, which is typically asymptomatic. A minor case of microcytic anemia may be present.
Definition • A collection of hereditary erythrocyte diseases resulting from the insufficient synthesis of alpha or beta globin chains. Pathogenesis • Insufficient production of either A- or B-globin chains results in the accumulation of surplus unpaired chains. • This culminates in the destruction of developing erythrocytes and the premature elimination of circulating erythrocytes in the spleen. The anemia in thalassaemia results from a combination of inadequate erythropoiesis and splenic haemolysis. Beta-thalassemia major • Resulting from mutations in both B-globin genes.
• Complications arise within the initial months of life as HbF levels diminish and surplus A-chains start to build in erythrocytes. • Deteriorating anaemia results in heightened erythropoietic stimulation, causing an increase in the bone marrow volume and the reactivation of extramedullary haematopoiesis.
• Manifestations in infancy include pallor, inadequate feeding, and growth failure. • The complete blood count indicates hypochromic, microcytic anemia. • The diagnosis is corroborated by the nearly absent HbA on hemoglobin electrophoresis. Beta-thalassemia minor • Resulting from mutations in a single B-globin gene.
• Asymptomatic silent carriers exhibit moderate microcytic anemia. • An elevated HbA2 level on hemoglobin electrophoresis is a critical diagnostic indicator. Alpha-thalassemia • A-chains are essential for both adult and fetal hemoglobin. • In the fetus, surplus G-chains aggregate to form tetramers referred to as Hb Bart's. In adulthood, surplus B-chains aggregate to form tetramers referred to as HbH. The deletion of all four A-globin genes results in severe fetal anemia, widespread edema, major hepatosplenomegaly, and fetal demise between 28 and 40 weeks of gestation. The deletion of three alpha-globin genes results in HbH illness, characterized by varying degrees of persistent hemolysis. The majority of individuals experience moderate chronic hemolytic anemia throughout their lives (Hb 7–10 g/dL) accompanied by splenomegaly. Deletion of one or two alpha-globin genes results in alpha-thalassemia minor, which is typically asymptomatic. A minor case of microcytic anemia may be present.
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Pathology - Sickle cell disorders
Definition: A collection of hereditary red blood cell diseases resulting from HbS.
Epidemiology • Most commonly observed in individuals of African heritage and regions with current or historical malaria endemicity. The mutant gene persists as heterozygote carriers are safeguarded against the severe effects of Plasmodium falciparum malaria.
Genetics: HbS results from a point mutation in the β-globin gene located on chromosome 11, leading to a substitution of glutamic acid with valine. Heterozygotes are characterized by possessing sickle cell trait. • Homozygotes experience sickle cell disease or sickle cell anemia. Pathogenesis HbS exhibits a solubility that is 50 times inferior to that of HbA. Under low oxygen tension, HbS polymerizes into rod-like aggregates, resulting in the red blood cell adopting a sickled morphology.
Presentation • Individuals possessing sickle cell trait do not experience sickling due to the presence of normal HbA protein, which diminishes the aggregation of HbS. Patients are typically asymptomatic and exhibit normal hemoglobin levels. They are, nonetheless, genetically significant as carriers of the sickle cell allele. Individuals with sickle cell disease typically manifest symptoms at the age of two, after depleting most of their HbF, resulting in nearly all hemoglobin being HbS. Their red blood cells undergo sickling in venous blood, resulting in chronic hemolysis and episodes of vascular crises.
Complete blood count: Decreased hemoglobin, often ranging from 7 to 9 g/dL.
Peripheral blood smear • Sickle-shaped erythrocytes and their variations are present. • In adults, evidence of hyposplenism is present, shown by target cells, Howell–Jolly bodies, and Pappenheimer bodies. Diagnosis • The sickle cell solubility test serves as an effective screening method wherein a reducing agent is included into hemoglobin recovered from erythrocytes. HbS rapidly precipitates, resulting in a turbid solution. Definitive diagnosis necessitates Hb electrophoresis, which reveals a singular predominant HbS band and the absence of normal HbA.
Prognosis: Patients with sickle cell disease exhibit a markedly reduced lifetime. The median age of death is approximately 42 years for males and 48 years for women.
Complications associated with sickle cell disease Childhood: Hand-foot syndrome. • Splenic sequestration crisis. • Cerebrovascular accident. Subsequent years • Bacterial infections. • End-stage renal disease. • Priapism. • Ulceration of the lower extremities. • Pigmentary gallstones. • Avascular necrosis of the femoral head. • Pulmonary syndrome.
Definition: A collection of hereditary red blood cell diseases resulting from HbS.
Epidemiology • Most commonly observed in individuals of African heritage and regions with current or historical malaria endemicity. The mutant gene persists as heterozygote carriers are safeguarded against the severe effects of Plasmodium falciparum malaria.
Genetics: HbS results from a point mutation in the β-globin gene located on chromosome 11, leading to a substitution of glutamic acid with valine. Heterozygotes are characterized by possessing sickle cell trait. • Homozygotes experience sickle cell disease or sickle cell anemia. Pathogenesis HbS exhibits a solubility that is 50 times inferior to that of HbA. Under low oxygen tension, HbS polymerizes into rod-like aggregates, resulting in the red blood cell adopting a sickled morphology.
Presentation • Individuals possessing sickle cell trait do not experience sickling due to the presence of normal HbA protein, which diminishes the aggregation of HbS. Patients are typically asymptomatic and exhibit normal hemoglobin levels. They are, nonetheless, genetically significant as carriers of the sickle cell allele. Individuals with sickle cell disease typically manifest symptoms at the age of two, after depleting most of their HbF, resulting in nearly all hemoglobin being HbS. Their red blood cells undergo sickling in venous blood, resulting in chronic hemolysis and episodes of vascular crises.
Complete blood count: Decreased hemoglobin, often ranging from 7 to 9 g/dL.
Peripheral blood smear • Sickle-shaped erythrocytes and their variations are present. • In adults, evidence of hyposplenism is present, shown by target cells, Howell–Jolly bodies, and Pappenheimer bodies. Diagnosis • The sickle cell solubility test serves as an effective screening method wherein a reducing agent is included into hemoglobin recovered from erythrocytes. HbS rapidly precipitates, resulting in a turbid solution. Definitive diagnosis necessitates Hb electrophoresis, which reveals a singular predominant HbS band and the absence of normal HbA.
Prognosis: Patients with sickle cell disease exhibit a markedly reduced lifetime. The median age of death is approximately 42 years for males and 48 years for women.
Complications associated with sickle cell disease Childhood: Hand-foot syndrome. • Splenic sequestration crisis. • Cerebrovascular accident. Subsequent years • Bacterial infections. • End-stage renal disease. • Priapism. • Ulceration of the lower extremities. • Pigmentary gallstones. • Avascular necrosis of the femoral head. • Pulmonary syndrome.
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Pathology - Idiopathic thrombocytopenic purpura
Definition: A decrease in platelet count resulting from autoimmune damage.
Epidemiology • Rare, with an occurrence of 1 in 100,000. • Affects both adults and children. • Adult idiopathic thrombocytopenic purpura (ITP) exhibits a higher prevalence in women, with a ratio of 3:1. Childhood ITP exhibits a peak incidence between the ages of 2 and 4, with no gender preference.
Aetiology • The formation of platelet autoantibodies occurs for unidentified reasons.
Pathogenesis: Platelets are coated with autoantibodies and subsequently destroyed in the spleen.
Presentation • Abrupt emergence of cutaneous petechiae, epistaxis, and gingival hemorrhage. • A prior viral infection is frequently observed in pediatric cases. Complete blood count • Profound thrombocytopenia. • Normal hemoglobin and leukocyte count.
Peripheral blood smear
A combination of normal and enlarged platelets is observed. Bone marrow findings • Normal or elevated quantities of megakaryocytes.
• Typical megakaryocyte
morphology. • Typical haematopoiesis. 2 ITP is a diagnosis of exclusion when other causes of thrombocytopenia have been eliminated.
Prognosis: Childhood instances often resolve within one to two months. Adult instances are more prone to exhibit a chronic mild-to-moderate bleeding tendency.
Definition: A decrease in platelet count resulting from autoimmune damage.
Epidemiology • Rare, with an occurrence of 1 in 100,000. • Affects both adults and children. • Adult idiopathic thrombocytopenic purpura (ITP) exhibits a higher prevalence in women, with a ratio of 3:1. Childhood ITP exhibits a peak incidence between the ages of 2 and 4, with no gender preference.
Aetiology • The formation of platelet autoantibodies occurs for unidentified reasons.
Pathogenesis: Platelets are coated with autoantibodies and subsequently destroyed in the spleen.
Presentation • Abrupt emergence of cutaneous petechiae, epistaxis, and gingival hemorrhage. • A prior viral infection is frequently observed in pediatric cases. Complete blood count • Profound thrombocytopenia. • Normal hemoglobin and leukocyte count.
Peripheral blood smear
A combination of normal and enlarged platelets is observed. Bone marrow findings • Normal or elevated quantities of megakaryocytes.
• Typical megakaryocyte
morphology. • Typical haematopoiesis. 2 ITP is a diagnosis of exclusion when other causes of thrombocytopenia have been eliminated.
Prognosis: Childhood instances often resolve within one to two months. Adult instances are more prone to exhibit a chronic mild-to-moderate bleeding tendency.
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Pathology - Thrombotic thrombocytopenic purpura
Definition: A thrombotic microangiopathy resulting from a deficiency of ADAMTS13.
Epidemiology • Uncommon.
Aetiology
Inherited instances result from genetic mutations in ADAMTS13. Sporadic cases result from autoantibodies targeting ADAMTS13.
Pathogenesis ADAMTS13 is a metalloproteinase that cleaves von Willebrand factor (vWF) into smaller fragments.
Deficiency of ADAMTS13 results in the accumulation of ultra-high molecular weight variants of vWF, which adhere to endothelial cells and promote microthrombus development in tiny arteries.
Microthrombi induce organ dysfunction, particularly impacting the brain and kidneys. • Platelets are swiftly depleted in the microthrombi, resulting in thrombocytopenia. Red blood cells traversing the microthrombi are fragmented, resulting in anemia.
Clinical Manifestation • Pyrexia, petechial rash, and hemorrhage. • Neurological manifestations are generally pronounced. • Acute renal failure may also manifest. Hematology • Decreased hemoglobin with normal mean corpuscular volume. •
Reticulocyte count. • Platelet count. • Standard coagulation. Blood film • Anisocytosis of red blood cells. • Notable schistocytes (fragmented erythrocytes).
Prognosis: Survival rates range from 80% to 90% with prompt diagnosis and plasma exchange. Approximately one-third of individuals experience relapses within two years.
Definition: A thrombotic microangiopathy resulting from a deficiency of ADAMTS13.
Epidemiology • Uncommon.
Aetiology
Inherited instances result from genetic mutations in ADAMTS13. Sporadic cases result from autoantibodies targeting ADAMTS13.
Pathogenesis ADAMTS13 is a metalloproteinase that cleaves von Willebrand factor (vWF) into smaller fragments.
Deficiency of ADAMTS13 results in the accumulation of ultra-high molecular weight variants of vWF, which adhere to endothelial cells and promote microthrombus development in tiny arteries.
Microthrombi induce organ dysfunction, particularly impacting the brain and kidneys. • Platelets are swiftly depleted in the microthrombi, resulting in thrombocytopenia. Red blood cells traversing the microthrombi are fragmented, resulting in anemia.
Clinical Manifestation • Pyrexia, petechial rash, and hemorrhage. • Neurological manifestations are generally pronounced. • Acute renal failure may also manifest. Hematology • Decreased hemoglobin with normal mean corpuscular volume. •
Reticulocyte count. • Platelet count. • Standard coagulation. Blood film • Anisocytosis of red blood cells. • Notable schistocytes (fragmented erythrocytes).
Prognosis: Survival rates range from 80% to 90% with prompt diagnosis and plasma exchange. Approximately one-third of individuals experience relapses within two years.
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Pathology - von Willebrand disease
Definition: An inherent predisposition to bleeding resulting from a quantitative or qualitative deficiency of von Willebrand factor (vWF).
Epidemiology The most prevalent hereditary coagulopathy. Type 1 (75%) constitutes a quantitative deficiency. Type 2 (20%) constitutes a qualitative flaw. Type 3, albeit less common, represents the most severe manifestation of the disease. The vWF gene resides on chromosome 12. Types 1 and 2 are transmitted in an autosomal dominant manner. Type 3 is an autosomal recessive characteristic.
Pathogenesis • von Willebrand factor (vWF) functions as an adhesion molecule, facilitating platelet attachment to subendothelial structures, and serves as a carrier for factor VIII. • Insufficient vWF activity results in a propensity for bleeding, attributable to impaired platelet adhesion and factor VIII deficiency. Presentation • The primary signs include mucosal hemorrhaging, especially epistaxis, and bleeding subsequent to trauma or surgical procedures.
Joint and muscle hemorrhages are infrequent and manifest solely in type 3 illness. Coagulation assessments • Extended activated partial thromboplastin time (APTT). • Extended hemorrhagic duration. • Normal prothrombin time (PT). Formal diagnosis necessitates the quantification of plasma von Willebrand factor (vWF) and the assessment of vWF functionality, such as through the ristocetin-induced platelet agglutination assay.
Prognosis: Most patients necessitate no further treatment. • Prophylactic therapy is used prior to surgery
Definition: An inherent predisposition to bleeding resulting from a quantitative or qualitative deficiency of von Willebrand factor (vWF).
Epidemiology The most prevalent hereditary coagulopathy. Type 1 (75%) constitutes a quantitative deficiency. Type 2 (20%) constitutes a qualitative flaw. Type 3, albeit less common, represents the most severe manifestation of the disease. The vWF gene resides on chromosome 12. Types 1 and 2 are transmitted in an autosomal dominant manner. Type 3 is an autosomal recessive characteristic.
Pathogenesis • von Willebrand factor (vWF) functions as an adhesion molecule, facilitating platelet attachment to subendothelial structures, and serves as a carrier for factor VIII. • Insufficient vWF activity results in a propensity for bleeding, attributable to impaired platelet adhesion and factor VIII deficiency. Presentation • The primary signs include mucosal hemorrhaging, especially epistaxis, and bleeding subsequent to trauma or surgical procedures.
Joint and muscle hemorrhages are infrequent and manifest solely in type 3 illness. Coagulation assessments • Extended activated partial thromboplastin time (APTT). • Extended hemorrhagic duration. • Normal prothrombin time (PT). Formal diagnosis necessitates the quantification of plasma von Willebrand factor (vWF) and the assessment of vWF functionality, such as through the ristocetin-induced platelet agglutination assay.
Prognosis: Most patients necessitate no further treatment. • Prophylactic therapy is used prior to surgery
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Pathology - Haemophilia
Definition • An inherited predisposition to bleeding resulting from a deficiency of either factor VIII (haemophilia A) or factor IX (haemophilia B).
Epidemiology Haemophilia A manifests in around 1 in 5,000 to 10,000 male births. Haemophilia B is rarer, with an incidence of about 1 in 20,000 to 30,000 male births. Genetics • The genes for factor VIII and factor IX are situated on the X chromosome, resulting in haemophilia exhibiting sex-linked inheritance, mostly affecting males. • A multitude of mutations have been documented, resulting in significant variability in the severity of haemophilia.
Pathogenesis Factors VIII and IX collectively constitute the factor VIII-factor IX complex, which activates factor X in the coagulation cascade. The absence of these factors hinders coagulation.
Presentation: • Susceptibility to bruising and significant hemorrhage following trauma or surgical procedures. • Spontaneous hemorrhages into major weight-bearing joints, including the knee, elbow, and ankles (hemarthroses), are prevalent. Coagulation assays • Both types of haemophilia result in an extended APTT and a normal PT. • The two can only be differentiated by assessing the levels of each factor.
Prognosis: The primary treatment intervention is the replacement of the deficient component. • Factor concentrates are aggregated from numerous donors and present a significantly elevated risk of infection transmission. • While rigorous donor screening and viral inactivation processes mitigate this danger, there is a trend towards the adoption of synthetic factors.
Definition • An inherited predisposition to bleeding resulting from a deficiency of either factor VIII (haemophilia A) or factor IX (haemophilia B).
Epidemiology Haemophilia A manifests in around 1 in 5,000 to 10,000 male births. Haemophilia B is rarer, with an incidence of about 1 in 20,000 to 30,000 male births. Genetics • The genes for factor VIII and factor IX are situated on the X chromosome, resulting in haemophilia exhibiting sex-linked inheritance, mostly affecting males. • A multitude of mutations have been documented, resulting in significant variability in the severity of haemophilia.
Pathogenesis Factors VIII and IX collectively constitute the factor VIII-factor IX complex, which activates factor X in the coagulation cascade. The absence of these factors hinders coagulation.
Presentation: • Susceptibility to bruising and significant hemorrhage following trauma or surgical procedures. • Spontaneous hemorrhages into major weight-bearing joints, including the knee, elbow, and ankles (hemarthroses), are prevalent. Coagulation assays • Both types of haemophilia result in an extended APTT and a normal PT. • The two can only be differentiated by assessing the levels of each factor.
Prognosis: The primary treatment intervention is the replacement of the deficient component. • Factor concentrates are aggregated from numerous donors and present a significantly elevated risk of infection transmission. • While rigorous donor screening and viral inactivation processes mitigate this danger, there is a trend towards the adoption of synthetic factors.
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Pathology - Proliferative breast diseases
Definition: A heterogeneous collection of intraductal proliferative lesions of the breast linked to a variable risk for the later emergence of invasive breast cancer. Epidemiology • Extremely prevalent. • Incidence has increased following the implementation of breast screening programs.
Aetiology • Comparable to invasive breast carcinoma (see p. 226). Genetics • The majority of instances of flat epithelial atypia and in situ lobular neoplasia exhibit genetic anomalies, particularly the loss of heterozygosity on chromosome 16p. A fraction of typical epithelial hyperplasia instances exhibit genetic abnormalities.
Macroscopy: The majority are detected through screening mammography or accidentally during the excision of breast tissue for other purposes. Histopathology • Usual epithelial hyperplasia is characterized by a disorganized proliferation of juvenile ductal epithelial cells that create slit-like spaces. • Flat epithelial atypia involves a consistent proliferation of moderately atypical ductal epithelial cells, not exceeding five cells in thickness. This is considered the earliest morphological precursor of low-grade ductal carcinoma in situ. In situ lobular neoplasia is characterized by a proliferation of tiny, weakly cohesive epithelial cells, marked by the loss of E-cadherin expression as determined immunohistochemically.
Prognosis • Typical epithelial hyperplasia is not regarded as a direct precursor lesion for invasive breast carcinoma; however, it serves as an indicator of a modestly elevated risk (relative risk of 1.5–2.0) for subsequent invasive carcinoma. • Currently, there is no quantitative data regarding the relative risk for the future development of invasive breast carcinoma in patients with flat epithelial atypia.
Recent genetic findings indicate that flat epithelial atypia may serve as the initial morphological precursor to low-grade ductal carcinoma in situ. Current research indicates that in situ lobular neoplasia poses a risk for eventual invasive breast carcinoma in either breast in a minority of women. The relative risk is reported to be between 7 and 12 times greater than that anticipated in women devoid of lobular neoplasia.
Definition: A heterogeneous collection of intraductal proliferative lesions of the breast linked to a variable risk for the later emergence of invasive breast cancer. Epidemiology • Extremely prevalent. • Incidence has increased following the implementation of breast screening programs.
Aetiology • Comparable to invasive breast carcinoma (see p. 226). Genetics • The majority of instances of flat epithelial atypia and in situ lobular neoplasia exhibit genetic anomalies, particularly the loss of heterozygosity on chromosome 16p. A fraction of typical epithelial hyperplasia instances exhibit genetic abnormalities.
Macroscopy: The majority are detected through screening mammography or accidentally during the excision of breast tissue for other purposes. Histopathology • Usual epithelial hyperplasia is characterized by a disorganized proliferation of juvenile ductal epithelial cells that create slit-like spaces. • Flat epithelial atypia involves a consistent proliferation of moderately atypical ductal epithelial cells, not exceeding five cells in thickness. This is considered the earliest morphological precursor of low-grade ductal carcinoma in situ. In situ lobular neoplasia is characterized by a proliferation of tiny, weakly cohesive epithelial cells, marked by the loss of E-cadherin expression as determined immunohistochemically.
Prognosis • Typical epithelial hyperplasia is not regarded as a direct precursor lesion for invasive breast carcinoma; however, it serves as an indicator of a modestly elevated risk (relative risk of 1.5–2.0) for subsequent invasive carcinoma. • Currently, there is no quantitative data regarding the relative risk for the future development of invasive breast carcinoma in patients with flat epithelial atypia.
Recent genetic findings indicate that flat epithelial atypia may serve as the initial morphological precursor to low-grade ductal carcinoma in situ. Current research indicates that in situ lobular neoplasia poses a risk for eventual invasive breast carcinoma in either breast in a minority of women. The relative risk is reported to be between 7 and 12 times greater than that anticipated in women devoid of lobular neoplasia.
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Pathology - Ductal carcinoma in situ
Definition: Neoplastic intraductal epithelial proliferation in the breast, possessing an inherent but not guaranteed risk of development to invasive breast cancer.
Epidemiology
• Prevalent. • The incidence has significantly risen following the implementation of breast screening programs. Aetiology: Risks analogous to invasive breast carcinoma
Genetics • Low-grade ductal carcinoma in situ (DCIS) frequently exhibits loss of homozygosity at 16p. High-grade DCIS has genetic distinctiveness characterized by a more intricate karyotype.
Presentation: 85% are identified on mammography as regions of microcalcification. • Ten percent exhibit clinical manifestations include a lump, nipple discharge, or eczematous alterations of the nipple (Paget's disease of the nipple). • Five percent are detected inadvertently in breast specimens excised for alternative purposes.
Macroscopy :DCIS is frequently macroscopically imperceptible, even to a seasoned pathologist. Extensive high-grade DCIS may present as gritty yellow flecks resulting from calcified necrotic debris within the affected ducts.
Histopathology: DCIS is categorized into low, middle, and high nuclear grades. Low-grade DCIS is characterized by small, uniform cells exhibiting cribriform, solid, or micropapillary patterns, with pronounced cellular polarization, wherein the nuclei are basally located and the apical cytoplasm is oriented towards the duct lumen. Central necrosis within the duct is unusual. Intermediate-grade DCIS exhibits cells characterized by moderately large nuclei and coarse chromatin, proliferating in solid, cribriform, or micropapillary architectures with a moderate level of cellular polarization. Central necrosis may be observed. High-grade DCIS exhibits cells characterized by big, significantly pleomorphic nuclei, clumped chromatin, conspicuous nucleoli, and diminished cellular polarization. Central necrosis is prevalent.
Prognosis: Complete surgical excision with clear margins is curative. The prognosis is contingent upon the persistence of malignant cells following treatment. Recurrence is more probable in cases of severe illness, elevated nuclear grade, and the existence of comedo necrosis.
Definition: Neoplastic intraductal epithelial proliferation in the breast, possessing an inherent but not guaranteed risk of development to invasive breast cancer.
Epidemiology
• Prevalent. • The incidence has significantly risen following the implementation of breast screening programs. Aetiology: Risks analogous to invasive breast carcinoma
Genetics • Low-grade ductal carcinoma in situ (DCIS) frequently exhibits loss of homozygosity at 16p. High-grade DCIS has genetic distinctiveness characterized by a more intricate karyotype.
Presentation: 85% are identified on mammography as regions of microcalcification. • Ten percent exhibit clinical manifestations include a lump, nipple discharge, or eczematous alterations of the nipple (Paget's disease of the nipple). • Five percent are detected inadvertently in breast specimens excised for alternative purposes.
Macroscopy :DCIS is frequently macroscopically imperceptible, even to a seasoned pathologist. Extensive high-grade DCIS may present as gritty yellow flecks resulting from calcified necrotic debris within the affected ducts.
Histopathology: DCIS is categorized into low, middle, and high nuclear grades. Low-grade DCIS is characterized by small, uniform cells exhibiting cribriform, solid, or micropapillary patterns, with pronounced cellular polarization, wherein the nuclei are basally located and the apical cytoplasm is oriented towards the duct lumen. Central necrosis within the duct is unusual. Intermediate-grade DCIS exhibits cells characterized by moderately large nuclei and coarse chromatin, proliferating in solid, cribriform, or micropapillary architectures with a moderate level of cellular polarization. Central necrosis may be observed. High-grade DCIS exhibits cells characterized by big, significantly pleomorphic nuclei, clumped chromatin, conspicuous nucleoli, and diminished cellular polarization. Central necrosis is prevalent.
Prognosis: Complete surgical excision with clear margins is curative. The prognosis is contingent upon the persistence of malignant cells following treatment. Recurrence is more probable in cases of severe illness, elevated nuclear grade, and the existence of comedo necrosis.
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Pathology - Invasive breast carcinomas
Definition: A collection of malignant epithelial tumors that infiltrate the breast and possess the ability to metastasize to distant locations. Epidemiology: The predominant cancer among women, with a lifetime risk of 1 in 8. • Incidence rates escalate significantly with advancing age, resulting in the majority of cases occurring in elderly women.
Aetiology: Early menarche, late menopause, elevated weight, excessive alcohol intake, oral contraceptive usage, and a favorable familial history are all correlated with an increased risk. Approximately 5% exhibit unequivocal indications of heredity. BRCA mutations confer a lifetime risk of invasive breast cancer of up to 85%.
Carcinogenesis • Recent genetic research has proposed that the evolution of breast cancer can be generally categorized into two types. The low-grade group, including low-grade invasive ductal carcinoma, classical lobular carcinoma, mucinous carcinoma, and tubular cancer, expresses hormone receptors, does not overexpress HER2, and lacks basal indicators. Genetically, they possess uncomplicated diploid or nearly diploid karyotypes and are characterized by the deletion of 16q and the amplification of 1q. The high-grade category (e.g., high-grade invasive ductal carcinoma, basal-like cancer) often lacks hormone receptors, overexpresses HER2, and exhibits basal signs. They possess intricate karyotypes characterized by several imbalanced chromosomal abnormalities. Common alterations encompass the deletion of 1p, 8p, and 17p, alongside the amplification of 1q and 8q.
Presentation • The majority of cases manifest symptomatically as a breast lump. • A growing percentage of asymptomatic cases are identified through screening mammography. Macroscopy Most breast carcinomas generate a solid stellate tumor within the breast. Cytopathology Fine needle aspiration (FNA) samples from breast carcinomas are generally characterized by high cellularity, comprising a poorly coherent assemblage of malignant epithelial cells.
Background: Bare bipolar nuclei are nonexistent. Histopathology Invasive ductal carcinomas, comprising 80%, are infiltrating carcinomas that lack distinctive features necessary for classification as specific histological types, such as lobular or tubular carcinoma; thus, they are often designated as 'no special kind.' Consequently, they constitute a heterogeneous array of tumors rather than a singular variety. In the future, this group is expected to be subdivided into more significant entities based on their genetic profiles.
Invasive lobular carcinomas (15%) consist of tiny, poorly cohesive cells with little cytoplasm, which typically proliferate in linear cords and wrap existing normal ducts.
Tubular carcinomas (5%) consist of well-organized tubular formations bordered by a single layer of epithelial cells exhibiting low-grade atypia.
Mucinous carcinomas (5%) are distinguished by the extensive synthesis of mucin in which the tumor cells are suspended. Basal-like carcinomas constitute a recently identified category of tumors revealed through the genetic profiling of several breast carcinomas. They frequently manifest in young women and are associated with BRCA mutations.
Morphologically, they generally exhibit sheets of markedly abnormal epithelial cells accompanied by a significant lymphocytic inflammatory infiltrate and central necrosis. Immunohistochemically, they are distinguished by the expression of basal-type keratins, such as cytokeratins 5 and 14. Basal-like tumors are often negative for estrogen receptors (ER) and progesterone receptors (PR), and are not amplified for Her2, hence classified as 'triple negative' tumors. These tumors exhibit a tendency for visceral metastasis, particularly to the lungs and brain.
Grading • All invasive breast tumors are histologically graded by evaluating nuclear pleomorphism, tubule development, and mitotic activity. Each attribute is evaluated on a scale from 1 to 3, and the cumulative scores yield a total ranging from 3 to 9. • 3–5 points represent grade 1 (well-differentiated). • 6–7 points = grade 2 (moderately differentiated). • 8–9 points = grade 3 (insufficiently differentiated). The primary prognostic determinant is the condition of the axillary lymph nodes. Additional significant criteria encompass tumor size, histology type, and histological grade.
Simplifi ed TNM 7 pathological staging of breast
carcinomas
Primary tumour (T)
pT1: tumour 2cm or less in size.
pT2: tumour > 2cm, but not > 5cm in size.
pT3: tumour > 5cm in size.
pT4: tumour of any size with extension to the chest wall and/or skin.
Regional lymph nodes (N)
pN0: no regional lymph node metastasis.
pN1: metastasis in 1–3 ipsilateral axillary lymph nodes.
pN2: metastasis in 4–9 ipsilateral axillary lymph nodes.
pN3: metastasis in 10 or more ipsilateral axillary lymph nod
Definition: A collection of malignant epithelial tumors that infiltrate the breast and possess the ability to metastasize to distant locations. Epidemiology: The predominant cancer among women, with a lifetime risk of 1 in 8. • Incidence rates escalate significantly with advancing age, resulting in the majority of cases occurring in elderly women.
Aetiology: Early menarche, late menopause, elevated weight, excessive alcohol intake, oral contraceptive usage, and a favorable familial history are all correlated with an increased risk. Approximately 5% exhibit unequivocal indications of heredity. BRCA mutations confer a lifetime risk of invasive breast cancer of up to 85%.
Carcinogenesis • Recent genetic research has proposed that the evolution of breast cancer can be generally categorized into two types. The low-grade group, including low-grade invasive ductal carcinoma, classical lobular carcinoma, mucinous carcinoma, and tubular cancer, expresses hormone receptors, does not overexpress HER2, and lacks basal indicators. Genetically, they possess uncomplicated diploid or nearly diploid karyotypes and are characterized by the deletion of 16q and the amplification of 1q. The high-grade category (e.g., high-grade invasive ductal carcinoma, basal-like cancer) often lacks hormone receptors, overexpresses HER2, and exhibits basal signs. They possess intricate karyotypes characterized by several imbalanced chromosomal abnormalities. Common alterations encompass the deletion of 1p, 8p, and 17p, alongside the amplification of 1q and 8q.
Presentation • The majority of cases manifest symptomatically as a breast lump. • A growing percentage of asymptomatic cases are identified through screening mammography. Macroscopy Most breast carcinomas generate a solid stellate tumor within the breast. Cytopathology Fine needle aspiration (FNA) samples from breast carcinomas are generally characterized by high cellularity, comprising a poorly coherent assemblage of malignant epithelial cells.
Background: Bare bipolar nuclei are nonexistent. Histopathology Invasive ductal carcinomas, comprising 80%, are infiltrating carcinomas that lack distinctive features necessary for classification as specific histological types, such as lobular or tubular carcinoma; thus, they are often designated as 'no special kind.' Consequently, they constitute a heterogeneous array of tumors rather than a singular variety. In the future, this group is expected to be subdivided into more significant entities based on their genetic profiles.
Invasive lobular carcinomas (15%) consist of tiny, poorly cohesive cells with little cytoplasm, which typically proliferate in linear cords and wrap existing normal ducts.
Tubular carcinomas (5%) consist of well-organized tubular formations bordered by a single layer of epithelial cells exhibiting low-grade atypia.
Mucinous carcinomas (5%) are distinguished by the extensive synthesis of mucin in which the tumor cells are suspended. Basal-like carcinomas constitute a recently identified category of tumors revealed through the genetic profiling of several breast carcinomas. They frequently manifest in young women and are associated with BRCA mutations.
Morphologically, they generally exhibit sheets of markedly abnormal epithelial cells accompanied by a significant lymphocytic inflammatory infiltrate and central necrosis. Immunohistochemically, they are distinguished by the expression of basal-type keratins, such as cytokeratins 5 and 14. Basal-like tumors are often negative for estrogen receptors (ER) and progesterone receptors (PR), and are not amplified for Her2, hence classified as 'triple negative' tumors. These tumors exhibit a tendency for visceral metastasis, particularly to the lungs and brain.
Grading • All invasive breast tumors are histologically graded by evaluating nuclear pleomorphism, tubule development, and mitotic activity. Each attribute is evaluated on a scale from 1 to 3, and the cumulative scores yield a total ranging from 3 to 9. • 3–5 points represent grade 1 (well-differentiated). • 6–7 points = grade 2 (moderately differentiated). • 8–9 points = grade 3 (insufficiently differentiated). The primary prognostic determinant is the condition of the axillary lymph nodes. Additional significant criteria encompass tumor size, histology type, and histological grade.
Simplifi ed TNM 7 pathological staging of breast
carcinomas
Primary tumour (T)
pT1: tumour 2cm or less in size.
pT2: tumour > 2cm, but not > 5cm in size.
pT3: tumour > 5cm in size.
pT4: tumour of any size with extension to the chest wall and/or skin.
Regional lymph nodes (N)
pN0: no regional lymph node metastasis.
pN1: metastasis in 1–3 ipsilateral axillary lymph nodes.
pN2: metastasis in 4–9 ipsilateral axillary lymph nodes.
pN3: metastasis in 10 or more ipsilateral axillary lymph nod
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Pathology – Breast Screening
The objective of screening is to detect DCIS or early invasive cancer. NHS mammography screening initiative Women between the ages of 50 and 70 are invited for screening every three years. • By 2012, this will encompass women aged 47 to 73. The screening test is a mammography that detects abnormal calcifications or masses in the breast. Evaluation clinic Approximately 5% of women exhibit abnormal mammography results and are subsequently sent to an assessment center for additional evaluation. • This may need further mammograms or an ultrasound, succeeded by sample of the anomalous region, typically via core biopsy.
Histopathology
Core biopsies obtained from breast screening patients are assigned a B code ranging from 1 to 5. B1 denotes normal breast tissue. This typically indicates that the biopsy overlooked the region of interest. B2 is a core exhibiting a benign anomaly. This is suitable for several lesions, including fibromas, fibrocystic changes, sclerosing adenosis, and fat necrosis. B3 is a lesion with indeterminate malignant potential. This category mostly comprises lesions that may be benign at their core but exhibit heterogeneity or possess a slightly elevated risk of a nearby malignancy. This is suitable for cores exhibiting flat epithelial atypia, in situ lobular neoplasia, atypical ductal hyperplasia, partially sampled papillomas, phyllodes tumors, and radial scars. B4 is a core exhibiting characteristics indicative of malignancy; nonetheless, a definitive diagnosis is unattainable due to factors such as inadequate aberrant tissue or compression of the biopsy. B5 is a core biopsy exhibiting definitive characteristics of malignancy. This is categorized either B5a for ductal carcinoma in situ (DCIS) or B5b for invasive cancer.
Administration • B1: rebiopsy. • B2: provide reassurance and revert to standard recollection. • B3: resection of the anomalous region. • B4: rebiopsy or excision of the anomalous region. • B5: surgical resection via extensive local excision or mastectomy. Efficacy • According to published statistics, the NHS breast screening program saves approximately 1,250 lives annually.
The objective of screening is to detect DCIS or early invasive cancer. NHS mammography screening initiative Women between the ages of 50 and 70 are invited for screening every three years. • By 2012, this will encompass women aged 47 to 73. The screening test is a mammography that detects abnormal calcifications or masses in the breast. Evaluation clinic Approximately 5% of women exhibit abnormal mammography results and are subsequently sent to an assessment center for additional evaluation. • This may need further mammograms or an ultrasound, succeeded by sample of the anomalous region, typically via core biopsy.
Histopathology
Core biopsies obtained from breast screening patients are assigned a B code ranging from 1 to 5. B1 denotes normal breast tissue. This typically indicates that the biopsy overlooked the region of interest. B2 is a core exhibiting a benign anomaly. This is suitable for several lesions, including fibromas, fibrocystic changes, sclerosing adenosis, and fat necrosis. B3 is a lesion with indeterminate malignant potential. This category mostly comprises lesions that may be benign at their core but exhibit heterogeneity or possess a slightly elevated risk of a nearby malignancy. This is suitable for cores exhibiting flat epithelial atypia, in situ lobular neoplasia, atypical ductal hyperplasia, partially sampled papillomas, phyllodes tumors, and radial scars. B4 is a core exhibiting characteristics indicative of malignancy; nonetheless, a definitive diagnosis is unattainable due to factors such as inadequate aberrant tissue or compression of the biopsy. B5 is a core biopsy exhibiting definitive characteristics of malignancy. This is categorized either B5a for ductal carcinoma in situ (DCIS) or B5b for invasive cancer.
Administration • B1: rebiopsy. • B2: provide reassurance and revert to standard recollection. • B3: resection of the anomalous region. • B4: rebiopsy or excision of the anomalous region. • B5: surgical resection via extensive local excision or mastectomy. Efficacy • According to published statistics, the NHS breast screening program saves approximately 1,250 lives annually.
