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Pathology - Chronic lymphocytic leukemia
A malignant tumor consisting of tiny mature B-cells that typically coexpress CD5 and CD23.
Epidemiology The predominant leukemia, occurring at a rate of 5 per 100,000 individuals. • A condition prevalent among older persons, with a peak incidence occurring between the ages of 60 and 80 years. • Males are impacted twice as frequently as females.
Aetiology • Unidentified.
Pathogenesis The oncogenic B-cells progressively infiltrate the bone marrow and subsequently enter the peripheral circulation. • As the condition advances, lymph nodes become affected, followed by the liver and spleen. • In the terminal phases of the disease, the neoplastic cells dominate the bone marrow, resulting in bone marrow failure.
Presentation • Numerous people are diagnosed incidentally when a complete blood count indicates leukocytosis. The remainder exhibits lymphadenopathy or autoimmune manifestations, such autoimmune hemolytic anemia or autoimmune thrombocytopenia.
Peripheral blood film: Excess of mature lymphocytes. Smear cells are indicative of chronic lymphocytic leukaemia (CLL); they are neoplastic cells that get blurred during film preparation. Histopathology • Lymph nodes are substituted by small, slightly atypical B-cells exhibiting varied quantities of proliferation centers comprising bigger lymphoid cells. • Affected bone marrow contains aggregates of neoplastic lymphoid cells. Immunophenotype: Positive for PAX5, CD20, CD79a, CD5, and CD23. • Cyclin D1 is negative.
Prognosis • Typically exhibits an indolent course, with several patients surviving for several years post-diagnosis, frequently without intervention. • A minority of cases are compounded by the emergence of diffuse large B-cell lymphoma (Richter’s syndrome), which carries a bad prognosis.
A malignant tumor consisting of tiny mature B-cells that typically coexpress CD5 and CD23.
Epidemiology The predominant leukemia, occurring at a rate of 5 per 100,000 individuals. • A condition prevalent among older persons, with a peak incidence occurring between the ages of 60 and 80 years. • Males are impacted twice as frequently as females.
Aetiology • Unidentified.
Pathogenesis The oncogenic B-cells progressively infiltrate the bone marrow and subsequently enter the peripheral circulation. • As the condition advances, lymph nodes become affected, followed by the liver and spleen. • In the terminal phases of the disease, the neoplastic cells dominate the bone marrow, resulting in bone marrow failure.
Presentation • Numerous people are diagnosed incidentally when a complete blood count indicates leukocytosis. The remainder exhibits lymphadenopathy or autoimmune manifestations, such autoimmune hemolytic anemia or autoimmune thrombocytopenia.
Peripheral blood film: Excess of mature lymphocytes. Smear cells are indicative of chronic lymphocytic leukaemia (CLL); they are neoplastic cells that get blurred during film preparation. Histopathology • Lymph nodes are substituted by small, slightly atypical B-cells exhibiting varied quantities of proliferation centers comprising bigger lymphoid cells. • Affected bone marrow contains aggregates of neoplastic lymphoid cells. Immunophenotype: Positive for PAX5, CD20, CD79a, CD5, and CD23. • Cyclin D1 is negative.
Prognosis • Typically exhibits an indolent course, with several patients surviving for several years post-diagnosis, frequently without intervention. • A minority of cases are compounded by the emergence of diffuse large B-cell lymphoma (Richter’s syndrome), which carries a bad prognosis.
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Pathology - Chronic myelogenous leukemia
A myeloproliferative neoplasm mostly affecting the granulocytic lineage, consistently related with the BCR-ABL1 fusion gene on the Philadelphia chromosome.
Epidemiology • Incidence ranges from 1 to 2 per 100,000 individuals annually. • The peak age of onset is between 50 and 70 years old.
Aetiology: Unknown. Genetics • Chronic myelogenous leukaemia (CML) is typically characterized by the t(9;22) translocation, which produces the Philadelphia chromosome. • This translocation fuses the BCR gene on chromosome 22 with the ABL1 gene on chromosome 9. • The resulting BCR-ABL1 protein exhibits increased tyrosine kinase activity, resulting in the persistent activation of signal transduction pathways and uncontrolled proliferation of myeloid cells.
Presentation • The majority of patients receive a diagnosis during the chronic phase of the disease, characterized by an elevated white cell count. • Hepatosplenomegaly frequently accompanies the diagnosis.
Peripheral blood • Leukocytosis resulting from elevated neutrophil counts at various maturation phases. • Basophilia and eosinophilia are prevalent. No dysplasia is observed.
Bone marrow • Bone marrow trephines exhibit hypercellularity attributed to elevated quantities of neutrophils and their precursors. • Megakaryocytes are generally diminutive and hypolobated. • Blasts constitute less than 5% of marrow cells throughout the chronic phase.
Prognosis • The outcome has significantly improved following the introduction of the tyrosine kinase inhibitor, imatinib, resulting in 5-year survival rates of 80–90%. • Disease progression is typically indicated by an elevation in circulating blasts to over 10% (accelerated phase) and culminates in acute leukemia when blasts constitute more than 20% of circulating cells.
A myeloproliferative neoplasm mostly affecting the granulocytic lineage, consistently related with the BCR-ABL1 fusion gene on the Philadelphia chromosome.
Epidemiology • Incidence ranges from 1 to 2 per 100,000 individuals annually. • The peak age of onset is between 50 and 70 years old.
Aetiology: Unknown. Genetics • Chronic myelogenous leukaemia (CML) is typically characterized by the t(9;22) translocation, which produces the Philadelphia chromosome. • This translocation fuses the BCR gene on chromosome 22 with the ABL1 gene on chromosome 9. • The resulting BCR-ABL1 protein exhibits increased tyrosine kinase activity, resulting in the persistent activation of signal transduction pathways and uncontrolled proliferation of myeloid cells.
Presentation • The majority of patients receive a diagnosis during the chronic phase of the disease, characterized by an elevated white cell count. • Hepatosplenomegaly frequently accompanies the diagnosis.
Peripheral blood • Leukocytosis resulting from elevated neutrophil counts at various maturation phases. • Basophilia and eosinophilia are prevalent. No dysplasia is observed.
Bone marrow • Bone marrow trephines exhibit hypercellularity attributed to elevated quantities of neutrophils and their precursors. • Megakaryocytes are generally diminutive and hypolobated. • Blasts constitute less than 5% of marrow cells throughout the chronic phase.
Prognosis • The outcome has significantly improved following the introduction of the tyrosine kinase inhibitor, imatinib, resulting in 5-year survival rates of 80–90%. • Disease progression is typically indicated by an elevation in circulating blasts to over 10% (accelerated phase) and culminates in acute leukemia when blasts constitute more than 20% of circulating cells.
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Pathology - Polycythemia vera
A myeloproliferative neoplasm primarily affecting the erythroid lineage, typically linked to a somatic gain-of-function mutation in the JAK2 gene. Epidemiology: Incidence ranges from 1 to 2.5 cases per 100,000 individuals annually. The median age upon diagnosis is 60 years. • There is a minor masculine predominance.
Aetiology: Unknown. Genetics: Over 95% of cases exhibit the JAK2 V617F mutation, resulting in uncontrolled proliferation of all myeloid cells, particularly affecting the erythroid lineage. The advancement of the disease correlates with the development of chromosomal abnormalities.
Presentation • May be incidentally detected with a full blood count or manifest with symptoms associated with hyperviscosity (headache, dizziness, visual disturbances, venous or arterial thrombosis). • The majority of individuals exhibit plethoric conditions and hepatosplenomegaly. Complete blood count: elevated hemoglobin, increased red cell count, heightened hematocrit (HCT), and augmented packed cell volume (PCV). • Frequently, I monitor white blood cell count and platelet levels. The bone marrow exhibits hypercellularity resulting from an elevation in all myeloid lineages, termed 'panmyelosis.' Erythroid progenitors and megakaryocytes are the most prominent cell types. Megakaryocytes exhibit loose clustering and frequently demonstrate considerable variation in size and morphology.
Prognosis: Median survival exceeds 10 years with treatment. The majority of patients succumb to thrombosis or hemorrhage. Approximately 20% succumb to the progression of myelodysplasia or acute myeloid leukemia (AML).
A myeloproliferative neoplasm primarily affecting the erythroid lineage, typically linked to a somatic gain-of-function mutation in the JAK2 gene. Epidemiology: Incidence ranges from 1 to 2.5 cases per 100,000 individuals annually. The median age upon diagnosis is 60 years. • There is a minor masculine predominance.
Aetiology: Unknown. Genetics: Over 95% of cases exhibit the JAK2 V617F mutation, resulting in uncontrolled proliferation of all myeloid cells, particularly affecting the erythroid lineage. The advancement of the disease correlates with the development of chromosomal abnormalities.
Presentation • May be incidentally detected with a full blood count or manifest with symptoms associated with hyperviscosity (headache, dizziness, visual disturbances, venous or arterial thrombosis). • The majority of individuals exhibit plethoric conditions and hepatosplenomegaly. Complete blood count: elevated hemoglobin, increased red cell count, heightened hematocrit (HCT), and augmented packed cell volume (PCV). • Frequently, I monitor white blood cell count and platelet levels. The bone marrow exhibits hypercellularity resulting from an elevation in all myeloid lineages, termed 'panmyelosis.' Erythroid progenitors and megakaryocytes are the most prominent cell types. Megakaryocytes exhibit loose clustering and frequently demonstrate considerable variation in size and morphology.
Prognosis: Median survival exceeds 10 years with treatment. The majority of patients succumb to thrombosis or hemorrhage. Approximately 20% succumb to the progression of myelodysplasia or acute myeloid leukemia (AML).
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Pathology - Essential thrombocythemia
Definition: A myeloproliferative neoplasm mostly affecting the megakaryocytic lineage.
Epidemiology: Estimated incidence ranges from 0.5 to 2.5 cases per 100,000 individuals annually. • The majority of occurrences occur in adults aged 50 to 60. • There is no gender preference.
Aetiology: Unknown. Genetics • No established molecular genetic or cytogenetic abnormalities have been identified.
Presentation • Approximately fifty percent of patients are diagnosed incidentally due to a significantly elevated platelet count identified in a complete blood count. • The remaining patients exhibit symptoms associated with vascular occlusion or hemorrhage, including transient ischemic attacks, digital ischemia and gangrene, as well as major arterial and venous thrombosis. • Splenomegaly occurs in only a minority of patients. Complete blood count • Persistently high platelet count (> 450 × 10^9/L). The leukocyte and erythrocyte counts are typically within normal limits. The bone marrow has normal cellularity, although displays an elevated presence of huge and enormous megakaryocytes characterized by ample cytoplasm and severely lobated 'stag-horn' nuclei. There is no significant proliferation of erythroid or granulocytic lineages.
Prognosis: A rather indolent disease with a median survival of 10 to 15 years. • A minimal percentage of patients advance to bone marrow fibrosis or acute myeloid leukemia.
Definition: A myeloproliferative neoplasm mostly affecting the megakaryocytic lineage.
Epidemiology: Estimated incidence ranges from 0.5 to 2.5 cases per 100,000 individuals annually. • The majority of occurrences occur in adults aged 50 to 60. • There is no gender preference.
Aetiology: Unknown. Genetics • No established molecular genetic or cytogenetic abnormalities have been identified.
Presentation • Approximately fifty percent of patients are diagnosed incidentally due to a significantly elevated platelet count identified in a complete blood count. • The remaining patients exhibit symptoms associated with vascular occlusion or hemorrhage, including transient ischemic attacks, digital ischemia and gangrene, as well as major arterial and venous thrombosis. • Splenomegaly occurs in only a minority of patients. Complete blood count • Persistently high platelet count (> 450 × 10^9/L). The leukocyte and erythrocyte counts are typically within normal limits. The bone marrow has normal cellularity, although displays an elevated presence of huge and enormous megakaryocytes characterized by ample cytoplasm and severely lobated 'stag-horn' nuclei. There is no significant proliferation of erythroid or granulocytic lineages.
Prognosis: A rather indolent disease with a median survival of 10 to 15 years. • A minimal percentage of patients advance to bone marrow fibrosis or acute myeloid leukemia.
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Pathology - Mantle cell lymphoma
A mature B-cell neoplasm characterized by monomorphic, small to medium-sized lymphoid cells exhibiting uneven nuclear outlines and a CCND1 translocation.
Epidemiology • Constitutes 3–10% of all non-Hodgkin B-cell lymphomas. • Primarily occurs in adults, with a mean age of 60 years.
Aetiology: Unknown. Genetics • Nearly all instances exhibit a t(11;14) translocation involving the CCND1 (cyclin D1) and IGH genes. Deregulated expression of cyclin D1 leads to unrestrained proliferation of lymphoid cells.
Presentation: The majority of individuals exhibit lymph node involvement. The liver, spleen, bone marrow, or peripheral blood may also be affected. Extranodal areas, especially the gastrointestinal tract, may also be involved. Histopathology • Affected tissues are substituted by sheets of monomorphic, tiny to medium-sized lymphoid cells exhibiting irregular nuclear contours. • Hyalinized small blood arteries and dispersed epithelioid histiocytes are frequently observed. Immunophenotype: B-cell markers PAX5, CD20, and CD79a exhibit positivity. • CD5 and cyclin D1 exhibit positivity. • CD23 and CD10 are often negative.
Prognosis • Despite its unremarkable look, the prognosis is typically unfavorable, with a median survival of merely 3–5 years.
A mature B-cell neoplasm characterized by monomorphic, small to medium-sized lymphoid cells exhibiting uneven nuclear outlines and a CCND1 translocation.
Epidemiology • Constitutes 3–10% of all non-Hodgkin B-cell lymphomas. • Primarily occurs in adults, with a mean age of 60 years.
Aetiology: Unknown. Genetics • Nearly all instances exhibit a t(11;14) translocation involving the CCND1 (cyclin D1) and IGH genes. Deregulated expression of cyclin D1 leads to unrestrained proliferation of lymphoid cells.
Presentation: The majority of individuals exhibit lymph node involvement. The liver, spleen, bone marrow, or peripheral blood may also be affected. Extranodal areas, especially the gastrointestinal tract, may also be involved. Histopathology • Affected tissues are substituted by sheets of monomorphic, tiny to medium-sized lymphoid cells exhibiting irregular nuclear contours. • Hyalinized small blood arteries and dispersed epithelioid histiocytes are frequently observed. Immunophenotype: B-cell markers PAX5, CD20, and CD79a exhibit positivity. • CD5 and cyclin D1 exhibit positivity. • CD23 and CD10 are often negative.
Prognosis • Despite its unremarkable look, the prognosis is typically unfavorable, with a median survival of merely 3–5 years.
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Pathology - Plasma cell myeloma
Definition: A diffuse neoplasm of plasma cells originating from bone marrow, characterized by the presence of paraproteins in serum and/or urine.
Epidemiology • Incidence ranges from 3 to 5 per 100,000 individuals. •
Manifestations are observed in older persons, with a mean diagnostic age of 70 years. • There is a masculine predominance of 1.5:1.
Aetiology • Unidentified.
Pathogenesis The neoplastic plasma cells produce cytokines that activate osteoclasts, resulting in lytic bone lesions. Circulating paraprotein inhibits normal immunoglobulin synthesis, hence elevating the susceptibility to infections. Free light chains traversing the kidneys contribute to renal failure.
Presentation: • Ostealgia and recurring infections. • Anemia, elevated ESR, hypercalcemia, and renal dysfunction are prevalent.
Histopathology A definitive diagnosis necessitates a bone marrow biopsy. • The bone marrow exhibits an abundance of monoclonal plasma cells organized in clusters, nodules, or sheets. • Clonality can be confirmed immunohistochemically by demonstrating kappa or lambda light chain restriction.
Prognosis • Myeloma is an incurable condition. • Average survival is 3–4 years post-diagnosis.
Definition: A diffuse neoplasm of plasma cells originating from bone marrow, characterized by the presence of paraproteins in serum and/or urine.
Epidemiology • Incidence ranges from 3 to 5 per 100,000 individuals. •
Manifestations are observed in older persons, with a mean diagnostic age of 70 years. • There is a masculine predominance of 1.5:1.
Aetiology • Unidentified.
Pathogenesis The neoplastic plasma cells produce cytokines that activate osteoclasts, resulting in lytic bone lesions. Circulating paraprotein inhibits normal immunoglobulin synthesis, hence elevating the susceptibility to infections. Free light chains traversing the kidneys contribute to renal failure.
Presentation: • Ostealgia and recurring infections. • Anemia, elevated ESR, hypercalcemia, and renal dysfunction are prevalent.
Histopathology A definitive diagnosis necessitates a bone marrow biopsy. • The bone marrow exhibits an abundance of monoclonal plasma cells organized in clusters, nodules, or sheets. • Clonality can be confirmed immunohistochemically by demonstrating kappa or lambda light chain restriction.
Prognosis • Myeloma is an incurable condition. • Average survival is 3–4 years post-diagnosis.
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Pathology - Primary amyloidosis
Definition: A plasma cell neoplasm characterized by the accumulation of AL amyloid in several tissues.
Epidemiology • Uncommon ailment. The median age at diagnosis is 65 years, with a predominance of males.
Aetiology The majority of patients possess an underlying plasma cell neoplasm yet do not fulfill the diagnostic criteria for plasma cell myeloma. Pathogenesis • AL amyloid consists of immunoglobulin light chains produced by monoclonal plasma cells, which aggregate in diverse tissues in a β-pleated sheet configuration. • The deposited amyloid comprises both intact light chains and fragments of the variable NH2-terminal region.
Presentation • Clinical manifestations associated with amyloid accumulation in several organs. Commonly affected areas encompass the skin, kidneys, heart, liver, intestines, and peripheral nerves. Characteristic manifestations include purpura, peripheral neuropathy, cardiac insufficiency, nephrotic syndrome, and malabsorption.
Histopathology • Amyloid can be identified in several tissues as a pink, amorphous material. The Congo Amyloid exhibits red staining under ordinary light microscopy and 'apple green' under polarized light. Bone marrow biopsies generally reveal a little elevation in plasma cells, which may present as either normal or abnormal. The plasma cells exhibit monotypism for either kappa or lambda light chains.
Prognosis: • Dismal prognosis with a median survival of merely 2 years from diagnosis. The predominant cause of mortality is amyloid-related heart failure.
Definition: A plasma cell neoplasm characterized by the accumulation of AL amyloid in several tissues.
Epidemiology • Uncommon ailment. The median age at diagnosis is 65 years, with a predominance of males.
Aetiology The majority of patients possess an underlying plasma cell neoplasm yet do not fulfill the diagnostic criteria for plasma cell myeloma. Pathogenesis • AL amyloid consists of immunoglobulin light chains produced by monoclonal plasma cells, which aggregate in diverse tissues in a β-pleated sheet configuration. • The deposited amyloid comprises both intact light chains and fragments of the variable NH2-terminal region.
Presentation • Clinical manifestations associated with amyloid accumulation in several organs. Commonly affected areas encompass the skin, kidneys, heart, liver, intestines, and peripheral nerves. Characteristic manifestations include purpura, peripheral neuropathy, cardiac insufficiency, nephrotic syndrome, and malabsorption.
Histopathology • Amyloid can be identified in several tissues as a pink, amorphous material. The Congo Amyloid exhibits red staining under ordinary light microscopy and 'apple green' under polarized light. Bone marrow biopsies generally reveal a little elevation in plasma cells, which may present as either normal or abnormal. The plasma cells exhibit monotypism for either kappa or lambda light chains.
Prognosis: • Dismal prognosis with a median survival of merely 2 years from diagnosis. The predominant cause of mortality is amyloid-related heart failure.
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Pathology – Eczemas
Definition • A collection of inflammatory dermatoses clinically identified by an erythematous papulovesicular eruption and histologically defined by intraepidermal edema (spongiosis).
Atopic dermatitis • Chronic dermatitis prevalent in individuals with atopy. • A highly prevalent condition with incidence rates reaching up to 15%. • Generally manifests in newborns and children. • Clinically induces a pruritic erythematous papulovesicular eruption affecting the facial region and the extensor surfaces of the upper and lower limbs. Biopsies from acute lesions reveal epidermal spongiosis and dermal inflammation. Biopsies from subsequent lesions demonstrate epidermal thickening and hyperkeratosis accompanied by moderate spongiosis.
Contact dermatitis due to irritants • Inflammatory dermatosis induced by the direct toxic impact of an irritant. • A prevalent etiology of occupational dermatosis. • Clinically induces erythema accompanied by vesiculation. Biopsies reveal epidermal spongiosis and dermal inflammation.
Allergic contact dermatitis • Inflammatory dermatosis resulting from a delayed-type hypersensitivity response to an allergen to which the patient has been exposed. • A prevalent occupational dermatosis, notably documented among hairdressers. • Clinically induces pruritic papules and vesicles 12–48 hours post-exposure. • Frequent offenders comprise nickel, cosmetics, and edibles. Biopsies reveal epidermal spongiosis accompanied by vesicle development and an inflammatory infiltrate, typically including eosinophils.
Nummular dermatitis • Inflammatory dermatosis of indeterminate etiology. • Clinically presents as small papules and vesicles that merge into coin-shaped plaques. • Biopsies reveal epidermal spongiosis and inflammation in first lesions. Advanced lesions exhibit epidermal hyperplasia.
Seborrheic dermatitis • Prevalent inflammatory dermatological condition impacting 1–3% of the population. Evidence indicates it may stem from an atypical immunological response to Malassezia organisms, though this remains contentious. • Clinically presents with erythematous, scaly papules and plaques, occasionally exhibiting a greasy look, located on the scalp, ears, eyebrows, and nasolabial region. Biopsies reveal varied epidermal spongiosis and hyperplasia accompanied by overlaying parakeratosis centered on hair follicles.
Definition • A collection of inflammatory dermatoses clinically identified by an erythematous papulovesicular eruption and histologically defined by intraepidermal edema (spongiosis).
Atopic dermatitis • Chronic dermatitis prevalent in individuals with atopy. • A highly prevalent condition with incidence rates reaching up to 15%. • Generally manifests in newborns and children. • Clinically induces a pruritic erythematous papulovesicular eruption affecting the facial region and the extensor surfaces of the upper and lower limbs. Biopsies from acute lesions reveal epidermal spongiosis and dermal inflammation. Biopsies from subsequent lesions demonstrate epidermal thickening and hyperkeratosis accompanied by moderate spongiosis.
Contact dermatitis due to irritants • Inflammatory dermatosis induced by the direct toxic impact of an irritant. • A prevalent etiology of occupational dermatosis. • Clinically induces erythema accompanied by vesiculation. Biopsies reveal epidermal spongiosis and dermal inflammation.
Allergic contact dermatitis • Inflammatory dermatosis resulting from a delayed-type hypersensitivity response to an allergen to which the patient has been exposed. • A prevalent occupational dermatosis, notably documented among hairdressers. • Clinically induces pruritic papules and vesicles 12–48 hours post-exposure. • Frequent offenders comprise nickel, cosmetics, and edibles. Biopsies reveal epidermal spongiosis accompanied by vesicle development and an inflammatory infiltrate, typically including eosinophils.
Nummular dermatitis • Inflammatory dermatosis of indeterminate etiology. • Clinically presents as small papules and vesicles that merge into coin-shaped plaques. • Biopsies reveal epidermal spongiosis and inflammation in first lesions. Advanced lesions exhibit epidermal hyperplasia.
Seborrheic dermatitis • Prevalent inflammatory dermatological condition impacting 1–3% of the population. Evidence indicates it may stem from an atypical immunological response to Malassezia organisms, though this remains contentious. • Clinically presents with erythematous, scaly papules and plaques, occasionally exhibiting a greasy look, located on the scalp, ears, eyebrows, and nasolabial region. Biopsies reveal varied epidermal spongiosis and hyperplasia accompanied by overlaying parakeratosis centered on hair follicles.
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Pathology - Extranodal marginal zone lymphoma
Definition: An extranodal mature B-cell neoplasm primarily consisting of tiny neoplastic marginal zone cells.
Epidemiology • Constitutes 7–8% of all non-Hodgkin B-cell lymphomas. • Primarily occurs in adults with a mean age of 60. Locations of engagement • The gastrointestinal system constitutes 50% of all instances, with the stomach as the predominant site. • Additional locations encompass the lung, salivary gland, skin, thyroid, and breast.
Etiology • Gastric instances are generally linked to Helicobacter pylori. • Additional implicated species comprise Campylobacter jejuni (jejunum) and Borrelia burgdorferi (skin). • Autoimmune illnesses are also linked, such as Hashimoto’s thyroiditis (thyroid) and Sjögren’s syndrome (salivary gland). Pathogenesis • The majority of cases are preceded by a chronic inflammatory condition that results in the accumulation of extranodal lymphoid tissue. • Extended stimulation of lymphoid proliferation ultimately culminates in the transition into a neoplastic process.
Presentation • Symptoms associated with a mass at the affected location.
Histopathology • Affected tissues comprise a diverse assemblage of small neoplastic B-cells that encircle and may infiltrate the underlying reactive lymphoid follicles. • The cellular composition includes marginal zone cells, monocytoid-like cells, small lymphocytes, and dispersed immunoblasts and centroblast-like cells. • In epithelial-lined tissues, the neoplastic lymphoid cells generally infiltrate and obliterate the epithelium, resulting in lymphoepithelial lesions. Immunophenotype: B-cell markers PAX5, CD20, and CD79a are expressed positively. CD5, CD10, CD23, and cyclin D1 are all absent.
Prognosis: Exhibits indolent behavior with extended periods of disease-free remission post-treatment.
Definition: An extranodal mature B-cell neoplasm primarily consisting of tiny neoplastic marginal zone cells.
Epidemiology • Constitutes 7–8% of all non-Hodgkin B-cell lymphomas. • Primarily occurs in adults with a mean age of 60. Locations of engagement • The gastrointestinal system constitutes 50% of all instances, with the stomach as the predominant site. • Additional locations encompass the lung, salivary gland, skin, thyroid, and breast.
Etiology • Gastric instances are generally linked to Helicobacter pylori. • Additional implicated species comprise Campylobacter jejuni (jejunum) and Borrelia burgdorferi (skin). • Autoimmune illnesses are also linked, such as Hashimoto’s thyroiditis (thyroid) and Sjögren’s syndrome (salivary gland). Pathogenesis • The majority of cases are preceded by a chronic inflammatory condition that results in the accumulation of extranodal lymphoid tissue. • Extended stimulation of lymphoid proliferation ultimately culminates in the transition into a neoplastic process.
Presentation • Symptoms associated with a mass at the affected location.
Histopathology • Affected tissues comprise a diverse assemblage of small neoplastic B-cells that encircle and may infiltrate the underlying reactive lymphoid follicles. • The cellular composition includes marginal zone cells, monocytoid-like cells, small lymphocytes, and dispersed immunoblasts and centroblast-like cells. • In epithelial-lined tissues, the neoplastic lymphoid cells generally infiltrate and obliterate the epithelium, resulting in lymphoepithelial lesions. Immunophenotype: B-cell markers PAX5, CD20, and CD79a are expressed positively. CD5, CD10, CD23, and cyclin D1 are all absent.
Prognosis: Exhibits indolent behavior with extended periods of disease-free remission post-treatment.
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Pathology- Psoriasis
Definition • A chronic, recurrent dermatological condition characterized by aberrant hyperproliferation of the epidermis. Epidemiology • Prevalent, impacting approximately 2% of the population. • Average age of onset is 25 years.
Aetiology Current evidence indicates that psoriasis arises from an aberrant immune response to an environmental trigger in a genetically predisposed individual. • Factors recognized to provoke or intensify the disease encompass stress, infections, climate, alcohol consumption, smoking, and trauma. Genome-wide linkage study has identified a minimum of nine chromosomal loci linked to psoriasis, predominantly comprising genes that encode HLA proteins, cytokines, or cytokine receptors.
Pathogenesis Activated plasmacytoid dendritic cells in the skin travel to draining lymph nodes, where they facilitate the differentiation of naïve T-cells into type 1 and type 17 helper and cytotoxic T-cells. Effector T-cells migrate to the skin, where they produce cytokines such as IL-17, IL-22, IFN-γ, and TNF-α, which promote the hyperproliferation of epidermal keratinocytes. The typical presentation of psoriasis features well-defined erythematous oval plaques adorned with adhering silvery scales. The preferred locations are the elbows, knees, and scalp. Nail involvement frequently presents with pitting and onycholysis.
Guttate psoriasis is a clinical variation distinguished by tiny, erythematous papules measuring 1–5mm in size. Numerous instances are preceded by streptococcal infection. Severe psoriasis can lead to erythroderma (erythrodermic psoriasis).
Histopathology Typical lesions exhibit psoriasiform epidermal proliferation accompanied by thinning of the suprapapillary plates. Plaques of parakeratosis exhibit a reduction of the granular layer underlying the parakeratosis. Collections of neutrophils are observed in the stratum corneum (Munro microabscesses) and may also be present inside the stratum spinosum. The dermis comprises dilated capillaries and an inflammatory infiltrate. Prognosis • Typically follows a chronic trajectory. • Can substantially affect quality of life.
Definition • A chronic, recurrent dermatological condition characterized by aberrant hyperproliferation of the epidermis. Epidemiology • Prevalent, impacting approximately 2% of the population. • Average age of onset is 25 years.
Aetiology Current evidence indicates that psoriasis arises from an aberrant immune response to an environmental trigger in a genetically predisposed individual. • Factors recognized to provoke or intensify the disease encompass stress, infections, climate, alcohol consumption, smoking, and trauma. Genome-wide linkage study has identified a minimum of nine chromosomal loci linked to psoriasis, predominantly comprising genes that encode HLA proteins, cytokines, or cytokine receptors.
Pathogenesis Activated plasmacytoid dendritic cells in the skin travel to draining lymph nodes, where they facilitate the differentiation of naïve T-cells into type 1 and type 17 helper and cytotoxic T-cells. Effector T-cells migrate to the skin, where they produce cytokines such as IL-17, IL-22, IFN-γ, and TNF-α, which promote the hyperproliferation of epidermal keratinocytes. The typical presentation of psoriasis features well-defined erythematous oval plaques adorned with adhering silvery scales. The preferred locations are the elbows, knees, and scalp. Nail involvement frequently presents with pitting and onycholysis.
Guttate psoriasis is a clinical variation distinguished by tiny, erythematous papules measuring 1–5mm in size. Numerous instances are preceded by streptococcal infection. Severe psoriasis can lead to erythroderma (erythrodermic psoriasis).
Histopathology Typical lesions exhibit psoriasiform epidermal proliferation accompanied by thinning of the suprapapillary plates. Plaques of parakeratosis exhibit a reduction of the granular layer underlying the parakeratosis. Collections of neutrophils are observed in the stratum corneum (Munro microabscesses) and may also be present inside the stratum spinosum. The dermis comprises dilated capillaries and an inflammatory infiltrate. Prognosis • Typically follows a chronic trajectory. • Can substantially affect quality of life.
