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Pathology - Renal cell carcinoma
Definition: A malignant epithelial tumor originating in the kidney.
Epidemiology • Represents approximately 2% of all cancers globally. • Prevalent in developed nations, with an average incidence of approximately 10 per 100,000 in males and 3 per 100,000 in females.
Aetiology • Identified risk factors encompass smoking, hypertension, obesity, environmental toxins, and prolonged dialysis. Certain genetic disorders, such as von Hippel-Lindau and tuberous sclerosis, are linked to renal cell carcinoma (RCC). Genetics Clear cell renal cell carcinomas exhibit deletions on chromosome 3p. Papillary RCCs exhibit trisomy of chromosomes 7 and 17, together with the deletion of chromosomal Y in males. Chromophobe RCCs exhibit significant chromosomal deletions.
Presentation • Approximately fifty percent of all cases manifest as painless hematuria. • The majority of the remaining cases are detected incidentally by imaging. A minor percentage exhibits metastatic illness.
Macroscopy The tumors are typically located in the renal cortex. • The clear cell types exhibit heterogeneity, characterized by golden yellow regions. • Papillary tumors may exhibit friability. • Chromophobe tumors are often solid and brown-hued. Histopathology transparent cell RCC (70%) consists of cells exhibiting transparent or eosinophilic cytoplasm arranged within a fine vascular framework. • Papillary RCC (15%) exhibits a papillary or tubulopapillary development pattern and measures greater than 5 mm in size. Chromophobe RCC (5%) consists of layers of big cells characterized by well-defined cell boundaries. The tumor's vasculature is characterized by thick walls. The remaining components consist of a combination of uncommon subtypes, including collecting duct carcinoma and mucinous tubular and spindle cell carcinoma.
Prognosis • The overall five-year survival rate is around 60%. • Stage and grade are the primary prognostic determinants. • The prevalent grading system utilized is the four-tiered Fuhrman system, which assesses nuclear size, shape, chromatin structure, and nucleolar prominence. Grade 1 exhibits the most favorable outlook, while grade 4 demonstrates the least favorable.
TNM 7 pathological staging of renal cell carcinomas
Primary tumour (T)
pT1a: tumour d 4cm, limited to the kidney.
pT1b: tumour > 4cm, but d 7cm, limited to the kidney.
pT2a: tumour > 7cm, but d 10cm, limited to the kidney.
pT2b: tumour > 10cm, limited to the kidney.
pT3a: tumour extends into perinephric fat or renal veins.
pT3b: tumour extends into the vena cava below the diaphragm.
pT3c: tumour extends into the vena cava above the diaphragm.
pT4: tumour directly invades the adrenal gland or beyond the Gerota fascia.
Regional lymph nodes (N)
pN0: no regional lymph node metastasis.
pN1: metastasis in regional lymph node
Definition: A malignant epithelial tumor originating in the kidney.
Epidemiology • Represents approximately 2% of all cancers globally. • Prevalent in developed nations, with an average incidence of approximately 10 per 100,000 in males and 3 per 100,000 in females.
Aetiology • Identified risk factors encompass smoking, hypertension, obesity, environmental toxins, and prolonged dialysis. Certain genetic disorders, such as von Hippel-Lindau and tuberous sclerosis, are linked to renal cell carcinoma (RCC). Genetics Clear cell renal cell carcinomas exhibit deletions on chromosome 3p. Papillary RCCs exhibit trisomy of chromosomes 7 and 17, together with the deletion of chromosomal Y in males. Chromophobe RCCs exhibit significant chromosomal deletions.
Presentation • Approximately fifty percent of all cases manifest as painless hematuria. • The majority of the remaining cases are detected incidentally by imaging. A minor percentage exhibits metastatic illness.
Macroscopy The tumors are typically located in the renal cortex. • The clear cell types exhibit heterogeneity, characterized by golden yellow regions. • Papillary tumors may exhibit friability. • Chromophobe tumors are often solid and brown-hued. Histopathology transparent cell RCC (70%) consists of cells exhibiting transparent or eosinophilic cytoplasm arranged within a fine vascular framework. • Papillary RCC (15%) exhibits a papillary or tubulopapillary development pattern and measures greater than 5 mm in size. Chromophobe RCC (5%) consists of layers of big cells characterized by well-defined cell boundaries. The tumor's vasculature is characterized by thick walls. The remaining components consist of a combination of uncommon subtypes, including collecting duct carcinoma and mucinous tubular and spindle cell carcinoma.
Prognosis • The overall five-year survival rate is around 60%. • Stage and grade are the primary prognostic determinants. • The prevalent grading system utilized is the four-tiered Fuhrman system, which assesses nuclear size, shape, chromatin structure, and nucleolar prominence. Grade 1 exhibits the most favorable outlook, while grade 4 demonstrates the least favorable.
TNM 7 pathological staging of renal cell carcinomas
Primary tumour (T)
pT1a: tumour d 4cm, limited to the kidney.
pT1b: tumour > 4cm, but d 7cm, limited to the kidney.
pT2a: tumour > 7cm, but d 10cm, limited to the kidney.
pT2b: tumour > 10cm, limited to the kidney.
pT3a: tumour extends into perinephric fat or renal veins.
pT3b: tumour extends into the vena cava below the diaphragm.
pT3c: tumour extends into the vena cava above the diaphragm.
pT4: tumour directly invades the adrenal gland or beyond the Gerota fascia.
Regional lymph nodes (N)
pN0: no regional lymph node metastasis.
pN1: metastasis in regional lymph node
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Pathology - Non-malignant kidney neoplasms
Papillary adenoma • Benign renal epithelial neoplasm exhibiting a papillary or tubulopapillary structure, measuring 5mm or less. • Commonly identified accidentally in nephrectomy specimens or during autopsy. Macroscopically, they are well-defined cortical nodules measuring 5 mm or smaller. Histologically, they consist of non-atypical epithelial cells exhibiting papillary or tubulopapillary arrangements.
Oncocytoma • Benign oncocytic renal epithelial tumor typically identified incidentally in adults. • The majority of instances are sporadic; nevertheless, certain occurrences are linked to hereditary abnormalities (e.g., Birt–Hogg–Dubé syndrome). Macroscopically, they are well-defined tumors exhibiting a mahogany brown hue, frequently accompanied by core scarring. Histologically, they are distinguished by cells possessing rich granular eosinophilic cytoplasm, proliferating in nests inside an edematous stroma. Oncocytomas are benign tumors that lack the ability for metastatic dissemination. Nonetheless, substantial tumors are frequently resected. • The infiltration of tumor cells into perinephric fat may occur, and this has no detrimental effect.
Angiomyolipoma • A benign mesenchymal tumor of the kidney consisting of varying quantities of adipose tissue, smooth muscle, and robust blood arteries. • Predominantly occurring sporadically in adults, a minor percentage is linked to tuberous sclerosis. These are more likely to be many and bilateral. • While most are discovered inadvertently, they may occasionally manifest with flank pain resulting from hemorrhage into the tumor. Macroscopically, they present as lobulated kidney masses that may exhibit a yellow appearance if their fat content is elevated. Histologically, they consist of a combination of adipose tissue, smooth muscle bundles, and thick-walled blood arteries in varying proportions.
Cystic nephroma • Benign cystic renal tumor with a significant preference for women. • Macroscopically, they are enclosed multicystic lesions devoid of a solid component. The cysts are microscopically bordered by a singular layer of flattened cuboidal epithelial cells. The septa may exhibit cellular regions that resemble ovarian stroma, and notably, the nuclei of the cells within the septa frequently respond to antibodies targeting estrogen and progesterone receptors
Leiomyoma • Benign leiomyomas typically originating from the renal capsule. • The majority manifest in adults as incidental, tiny, well-defined capsular tumors. • Histologically, they exhibit bundles of unremarkable smooth muscle cells.
Renomedullary interstitial cell tumor • Frequently observed benign renal tumors that are sometimes discovered inadvertently during autopsy examinations of the kidneys. Macroscopically, they are little (1–5mm) white nodules located at the center of a medullary pyramid. Histologically, they consist of tiny stellate or polygonal cells embedded in a loose stroma. Entrapped tubules may be located near the periphery of the lesion.
Papillary adenoma • Benign renal epithelial neoplasm exhibiting a papillary or tubulopapillary structure, measuring 5mm or less. • Commonly identified accidentally in nephrectomy specimens or during autopsy. Macroscopically, they are well-defined cortical nodules measuring 5 mm or smaller. Histologically, they consist of non-atypical epithelial cells exhibiting papillary or tubulopapillary arrangements.
Oncocytoma • Benign oncocytic renal epithelial tumor typically identified incidentally in adults. • The majority of instances are sporadic; nevertheless, certain occurrences are linked to hereditary abnormalities (e.g., Birt–Hogg–Dubé syndrome). Macroscopically, they are well-defined tumors exhibiting a mahogany brown hue, frequently accompanied by core scarring. Histologically, they are distinguished by cells possessing rich granular eosinophilic cytoplasm, proliferating in nests inside an edematous stroma. Oncocytomas are benign tumors that lack the ability for metastatic dissemination. Nonetheless, substantial tumors are frequently resected. • The infiltration of tumor cells into perinephric fat may occur, and this has no detrimental effect.
Angiomyolipoma • A benign mesenchymal tumor of the kidney consisting of varying quantities of adipose tissue, smooth muscle, and robust blood arteries. • Predominantly occurring sporadically in adults, a minor percentage is linked to tuberous sclerosis. These are more likely to be many and bilateral. • While most are discovered inadvertently, they may occasionally manifest with flank pain resulting from hemorrhage into the tumor. Macroscopically, they present as lobulated kidney masses that may exhibit a yellow appearance if their fat content is elevated. Histologically, they consist of a combination of adipose tissue, smooth muscle bundles, and thick-walled blood arteries in varying proportions.
Cystic nephroma • Benign cystic renal tumor with a significant preference for women. • Macroscopically, they are enclosed multicystic lesions devoid of a solid component. The cysts are microscopically bordered by a singular layer of flattened cuboidal epithelial cells. The septa may exhibit cellular regions that resemble ovarian stroma, and notably, the nuclei of the cells within the septa frequently respond to antibodies targeting estrogen and progesterone receptors
Leiomyoma • Benign leiomyomas typically originating from the renal capsule. • The majority manifest in adults as incidental, tiny, well-defined capsular tumors. • Histologically, they exhibit bundles of unremarkable smooth muscle cells.
Renomedullary interstitial cell tumor • Frequently observed benign renal tumors that are sometimes discovered inadvertently during autopsy examinations of the kidneys. Macroscopically, they are little (1–5mm) white nodules located at the center of a medullary pyramid. Histologically, they consist of tiny stellate or polygonal cells embedded in a loose stroma. Entrapped tubules may be located near the periphery of the lesion.
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Pathology - Cystic renal disorders
Autosomal dominant polycystic kidney disease The predominant cystic renal disease, occurring in approximately 1 in 500 individuals, is a primary contributor to end-stage renal failure. • Ninety percent of cases result from a hereditary mutation in the PKD1 gene located on chromosome 16. Deficiencies in the functionality of the PKD1 protein result in cystic alterations in renal tubules and the degeneration of normal renal tissue. Most patients often present in adulthood, generally between the ages of 30 and 40, exhibiting hypertension, flank pain, and hematuria. The kidneys are significantly enlarged, exceeding 2 kg in weight, and are entirely substituted by cysts. Histologically, both kidneys have many cysts lined by flattened cuboidal epithelium, with minimal intervening normal renal parenchyma. Extra-renal symptoms encompass hepatic cysts and berry aneurysms. Subarachnoid hemorrhage resulting from a ruptured berry aneurysm is a severe consequence of adult polycystic kidney disease (APKD) and a prevalent cause of abrupt mortality.
Autosomal recessive polycystic kidney disease • A rare, hereditary condition resulting in bilateral polycystic kidneys and congenital hepatic fibrosis. • Induced by mutations in the PKHD1 gene located on chromosome 6p, which encodes the protein fibrocystin, a constituent of the cilia on collecting duct epithelial cells. • Morphologically, the kidneys are enlarged and exhibit numerous cysts. • Histologically, the cysts are bordered by flattened cuboidal epithelium. • Severe cases result in neonatal mortality due to pulmonary hypoplasia. • Patients with milder renal illness who survive into childhood experience congenital hepatic fibrosis and problems associated with portal hypertension.
Medullary cystic disease • Congenital occurrence of several cysts at the corticomedullary junction, ranging in size from less than 1 mm to 2 cm. The pediatric condition, juvenile nephronophthisis, is inherited in an autosomal recessive manner and is linked to mutations in the NPH1, NPH2, or NPH3 genes. The adult condition, uraemic medullary cystic disease, is inherited in an autosomal dominant manner and is linked to mutations in the MCDK1 or MCDK2 genes.
Medullary sponge kidney • Characterized by an abnormal expansion of the collecting ducts, resulting in microcystic alterations of the renal medullae and papillae accompanied by calcification. • This condition typically manifests in adulthood with recurrent infections. Acquired renal cystic disease • Formation of many bilateral cortical and medullary cysts in individuals with end-stage renal disease undergoing dialysis. An essential supplementary characteristic is the heightened prevalence of kidney tumors, which are frequently of the papillary variety and may be many.
Autosomal dominant polycystic kidney disease The predominant cystic renal disease, occurring in approximately 1 in 500 individuals, is a primary contributor to end-stage renal failure. • Ninety percent of cases result from a hereditary mutation in the PKD1 gene located on chromosome 16. Deficiencies in the functionality of the PKD1 protein result in cystic alterations in renal tubules and the degeneration of normal renal tissue. Most patients often present in adulthood, generally between the ages of 30 and 40, exhibiting hypertension, flank pain, and hematuria. The kidneys are significantly enlarged, exceeding 2 kg in weight, and are entirely substituted by cysts. Histologically, both kidneys have many cysts lined by flattened cuboidal epithelium, with minimal intervening normal renal parenchyma. Extra-renal symptoms encompass hepatic cysts and berry aneurysms. Subarachnoid hemorrhage resulting from a ruptured berry aneurysm is a severe consequence of adult polycystic kidney disease (APKD) and a prevalent cause of abrupt mortality.
Autosomal recessive polycystic kidney disease • A rare, hereditary condition resulting in bilateral polycystic kidneys and congenital hepatic fibrosis. • Induced by mutations in the PKHD1 gene located on chromosome 6p, which encodes the protein fibrocystin, a constituent of the cilia on collecting duct epithelial cells. • Morphologically, the kidneys are enlarged and exhibit numerous cysts. • Histologically, the cysts are bordered by flattened cuboidal epithelium. • Severe cases result in neonatal mortality due to pulmonary hypoplasia. • Patients with milder renal illness who survive into childhood experience congenital hepatic fibrosis and problems associated with portal hypertension.
Medullary cystic disease • Congenital occurrence of several cysts at the corticomedullary junction, ranging in size from less than 1 mm to 2 cm. The pediatric condition, juvenile nephronophthisis, is inherited in an autosomal recessive manner and is linked to mutations in the NPH1, NPH2, or NPH3 genes. The adult condition, uraemic medullary cystic disease, is inherited in an autosomal dominant manner and is linked to mutations in the MCDK1 or MCDK2 genes.
Medullary sponge kidney • Characterized by an abnormal expansion of the collecting ducts, resulting in microcystic alterations of the renal medullae and papillae accompanied by calcification. • This condition typically manifests in adulthood with recurrent infections. Acquired renal cystic disease • Formation of many bilateral cortical and medullary cysts in individuals with end-stage renal disease undergoing dialysis. An essential supplementary characteristic is the heightened prevalence of kidney tumors, which are frequently of the papillary variety and may be many.
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Pathology - Reflux nephropathy
Definition: Renal scarring linked to vesicoureteric reflux (VUR), a congenital condition characterized by the retrograde flow of urine from the bladder into the upper urinary tract.
Epidemiology: A significant contributor to chronic kidney disease, accounting for around 30% of cases in pediatric populations and 10% in adults.
Aetiology: Vesicoureteral Reflux (VUR). It is important to note that not all cases of vesicoureteral reflux (VUR) are complicated by reflux nephropathy (RN).
Pathogenesis • Believed to be caused by the reflux of contaminated urine into the kidney. Intra-renal reflux typically occurs near the poles of the kidneys, where compound papillae are located. Compound papillae exhibit increased susceptibility to reflux due to the papillary ducts opening at less oblique angles onto a flat or concave surface. The immediate inflammatory reaction to the infection results in kidney scarring. • The loss of adequate nephron mass leads to the progression of renal disease.
Presentation • Patients commonly have hypertension and/or proteinuria. • When renal scarring is substantial, biochemical indicators of renal failure become apparent.
Macroscopy • The renal poles have regions of coarse cortical scarring. Histopathology: The scarred regions exhibit characteristics of chronic pyelonephritis, including tubular atrophy and interstitial fibrosis, accompanied by a mononuclear inflammatory cell infiltrate. Some tubules are collapsed, while others may be dilated and filled with proteinaceous material, a condition referred to as 'thyroidization.' • Remaining glomeruli exhibit hypertrophy and subsequent glomerulosclerosis.
This constellation of characteristics is not exclusive to reflux nephropathy and may also be observed in other situations, including obstructive nephropathy. The differentiation between the two is typically achievable, depending on the clinical presentation and the scarring pattern.
Complications • Recurrent urinary tract infections. • Renal calculi. • Chronic kidney disease
Definition: Renal scarring linked to vesicoureteric reflux (VUR), a congenital condition characterized by the retrograde flow of urine from the bladder into the upper urinary tract.
Epidemiology: A significant contributor to chronic kidney disease, accounting for around 30% of cases in pediatric populations and 10% in adults.
Aetiology: Vesicoureteral Reflux (VUR). It is important to note that not all cases of vesicoureteral reflux (VUR) are complicated by reflux nephropathy (RN).
Pathogenesis • Believed to be caused by the reflux of contaminated urine into the kidney. Intra-renal reflux typically occurs near the poles of the kidneys, where compound papillae are located. Compound papillae exhibit increased susceptibility to reflux due to the papillary ducts opening at less oblique angles onto a flat or concave surface. The immediate inflammatory reaction to the infection results in kidney scarring. • The loss of adequate nephron mass leads to the progression of renal disease.
Presentation • Patients commonly have hypertension and/or proteinuria. • When renal scarring is substantial, biochemical indicators of renal failure become apparent.
Macroscopy • The renal poles have regions of coarse cortical scarring. Histopathology: The scarred regions exhibit characteristics of chronic pyelonephritis, including tubular atrophy and interstitial fibrosis, accompanied by a mononuclear inflammatory cell infiltrate. Some tubules are collapsed, while others may be dilated and filled with proteinaceous material, a condition referred to as 'thyroidization.' • Remaining glomeruli exhibit hypertrophy and subsequent glomerulosclerosis.
This constellation of characteristics is not exclusive to reflux nephropathy and may also be observed in other situations, including obstructive nephropathy. The differentiation between the two is typically achievable, depending on the clinical presentation and the scarring pattern.
Complications • Recurrent urinary tract infections. • Renal calculi. • Chronic kidney disease
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Pathology - Anti-glomerular Basement Membrane Disease
Definition: A severe kidney illness induced by the production of autoantibodies against the glomerular basement membrane.
Epidemiology • Rare. The peak incidence occurs in adults aged 20 to 40 years.
Aetiology: Autoantibodies against the C-terminal region of type IV collagen.
Pathogenesis • Autoantibodies bind to the glomerular basement membrane, causing an autoimmune attack on the glomeruli.
Presentation: ARF caused by significant acute glomerular damage. Some individuals may experience pulmonary hemorrhage if the autoantibody also reacts with the alveolar basement membrane.
Light microscopy • Glomeruli exhibit segmental, necrotizing glomerulonephritis, with breaks in the glomerular basement membrane and production of crescents in the Bowman's space. • Unaffected segments of the glomeruli appear normal. • A lymphoplasmacytic immune cell infiltrate is found in the interstitium of afflicted glomeruli. immune fluorescence • IgG and C3 exhibit strong linear staining in the glomerular basement membrane. • Linear staining may also be observed in tubular basement membranes.
Electron microscopy • There are no immunological deposits present.
Prognosis: Prompt immunosuppressive therapy can limit disease activity, although renal damage may be irreversible.
Definition: A severe kidney illness induced by the production of autoantibodies against the glomerular basement membrane.
Epidemiology • Rare. The peak incidence occurs in adults aged 20 to 40 years.
Aetiology: Autoantibodies against the C-terminal region of type IV collagen.
Pathogenesis • Autoantibodies bind to the glomerular basement membrane, causing an autoimmune attack on the glomeruli.
Presentation: ARF caused by significant acute glomerular damage. Some individuals may experience pulmonary hemorrhage if the autoantibody also reacts with the alveolar basement membrane.
Light microscopy • Glomeruli exhibit segmental, necrotizing glomerulonephritis, with breaks in the glomerular basement membrane and production of crescents in the Bowman's space. • Unaffected segments of the glomeruli appear normal. • A lymphoplasmacytic immune cell infiltrate is found in the interstitium of afflicted glomeruli. immune fluorescence • IgG and C3 exhibit strong linear staining in the glomerular basement membrane. • Linear staining may also be observed in tubular basement membranes.
Electron microscopy • There are no immunological deposits present.
Prognosis: Prompt immunosuppressive therapy can limit disease activity, although renal damage may be irreversible.
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Pathology- Acute drug-induced interstitial nephritis
Definition: Renal impairment resulting from a hypersensitivity reaction to a medication.
Epidemiology • Rare.
Aetiology • Nonsteroidal anti-inflammatory drugs (NSAIDs). • Antimicrobials. • Diuretics. • Allopurinol. • Proton pump inhibitors.
Pathogenesis: A hypersensitive reaction to the offending medication induces tubulointerstitial inflammation and tubular destruction. The usual presentation is acute respiratory failure accompanied by fever and rash. Numerous patients have eosinophilia, eosinophiluria, and elevated serum IgE levels. • Patients with NSAID-induced conditions may exhibit significant proteinuria. • Typically, symptoms manifest within days of initiating the medication, although in other instances, they may not appear until many months of exposure.
Macroscopy • The kidneys exhibit swelling, pallor, and increased weight.
Histopathology • The interstitium exhibits expansion due to edema and a heterogeneous inflammatory cell infiltrate, prominently including eosinophils, which may lead to the formation of eosinophilic microabscesses. • Lymphocytes are additionally observed infiltrating the tubules, a condition referred to as 'tubulitis.'
Prognosis: The discontinuation of the causative medication typically leads to full recovery.
Definition: Renal impairment resulting from a hypersensitivity reaction to a medication.
Epidemiology • Rare.
Aetiology • Nonsteroidal anti-inflammatory drugs (NSAIDs). • Antimicrobials. • Diuretics. • Allopurinol. • Proton pump inhibitors.
Pathogenesis: A hypersensitive reaction to the offending medication induces tubulointerstitial inflammation and tubular destruction. The usual presentation is acute respiratory failure accompanied by fever and rash. Numerous patients have eosinophilia, eosinophiluria, and elevated serum IgE levels. • Patients with NSAID-induced conditions may exhibit significant proteinuria. • Typically, symptoms manifest within days of initiating the medication, although in other instances, they may not appear until many months of exposure.
Macroscopy • The kidneys exhibit swelling, pallor, and increased weight.
Histopathology • The interstitium exhibits expansion due to edema and a heterogeneous inflammatory cell infiltrate, prominently including eosinophils, which may lead to the formation of eosinophilic microabscesses. • Lymphocytes are additionally observed infiltrating the tubules, a condition referred to as 'tubulitis.'
Prognosis: The discontinuation of the causative medication typically leads to full recovery.
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Pathology - Acute tubular injury
Definition: Acute renal impairment resulting from damage to renal tubules.
Epidemiology • A prevalent etiology of acute renal failure (ARF).
Aetiology • Ischemia resulting from extended hypoperfusion. • Nephrotoxins including pharmaceuticals, radiological contrast agents, uric acid, hemoglobin, myoglobin, and ethylene glycol.
Pathogenesis: Tubular epithelial cells have high metabolic activity and are highly susceptible to injury from ischemia or toxins.
Presentation: ARF. Macroscopy • The kidneys exhibit hypertrophy, with a mass exceeding 200 grams. The renal cortex exhibits a pale appearance on the sliced surface.
Histopathology:The affected tubules exhibit dilation, accompanied by the flattening of tubular epithelial cells and the disappearance of the brush boundary. Casts of desquamated necrotic epithelial cells may be observed in the lumen of distal tubules. • The interstitial compartment is enlarged due to edema, although there is no substantial infiltration of inflammatory cells. • Indicators of the underlying etiology may be evident, such as birefringent oxalate crystals in cases of ethylene glycol poisoning or pigmented casts in rhabdomyolysis.
Prognosis: Typically linked to a serious circulatory abnormality and a significant death rate.
Definition: Acute renal impairment resulting from damage to renal tubules.
Epidemiology • A prevalent etiology of acute renal failure (ARF).
Aetiology • Ischemia resulting from extended hypoperfusion. • Nephrotoxins including pharmaceuticals, radiological contrast agents, uric acid, hemoglobin, myoglobin, and ethylene glycol.
Pathogenesis: Tubular epithelial cells have high metabolic activity and are highly susceptible to injury from ischemia or toxins.
Presentation: ARF. Macroscopy • The kidneys exhibit hypertrophy, with a mass exceeding 200 grams. The renal cortex exhibits a pale appearance on the sliced surface.
Histopathology:The affected tubules exhibit dilation, accompanied by the flattening of tubular epithelial cells and the disappearance of the brush boundary. Casts of desquamated necrotic epithelial cells may be observed in the lumen of distal tubules. • The interstitial compartment is enlarged due to edema, although there is no substantial infiltration of inflammatory cells. • Indicators of the underlying etiology may be evident, such as birefringent oxalate crystals in cases of ethylene glycol poisoning or pigmented casts in rhabdomyolysis.
Prognosis: Typically linked to a serious circulatory abnormality and a significant death rate.
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Pathology - IgA nephropathy
Definition: A glomerulopathy characterized by IgA deposition in glomeruli, either dominant or co-dominant.
Epidemiology: • The most prevalent glomerulopathy worldwide. The cause of IgAN is unknown, although it can reoccur in transplanted kidneys, indicating a systemic issue. One suggestion is that an aberrant mucosal immune system creates a kind of IgA that is resistant to breakdown, enters the circulation, and deposits in glomeruli.
Pathogenesis: • Deposition of IgA in the mesangium affects glomerular function, causing blood and protein leaks into urine.
Presentation: Haematuria (microscopic or macroscopic) with proteinuria. Light microscopy shows that IgAN can cause glomeruli alterations ranging from modest mesangial enlargement to focal and diffuse proliferative lesions, with the possibility of crescents in severe cases. immune fluorescence • The mesangial region of the glomeruli has dominant or co-dominant IgA staining, as defined. Electron microscopy reveals immunological deposits in mesangial regions of glomeruli.
Prognosis: • Approximately one-third of patients acquire progressive renal disease.
• Clinical characteristics such as proteinuria, hypertension, and renal function might indicate progression. The Oxford classification of IgAN identifies four histological characteristics that predict the outcome: mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity, and tubular atrophy/interstitial fibrosis.
Definition: A glomerulopathy characterized by IgA deposition in glomeruli, either dominant or co-dominant.
Epidemiology: • The most prevalent glomerulopathy worldwide. The cause of IgAN is unknown, although it can reoccur in transplanted kidneys, indicating a systemic issue. One suggestion is that an aberrant mucosal immune system creates a kind of IgA that is resistant to breakdown, enters the circulation, and deposits in glomeruli.
Pathogenesis: • Deposition of IgA in the mesangium affects glomerular function, causing blood and protein leaks into urine.
Presentation: Haematuria (microscopic or macroscopic) with proteinuria. Light microscopy shows that IgAN can cause glomeruli alterations ranging from modest mesangial enlargement to focal and diffuse proliferative lesions, with the possibility of crescents in severe cases. immune fluorescence • The mesangial region of the glomeruli has dominant or co-dominant IgA staining, as defined. Electron microscopy reveals immunological deposits in mesangial regions of glomeruli.
Prognosis: • Approximately one-third of patients acquire progressive renal disease.
• Clinical characteristics such as proteinuria, hypertension, and renal function might indicate progression. The Oxford classification of IgAN identifies four histological characteristics that predict the outcome: mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity, and tubular atrophy/interstitial fibrosis.
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Pathology - Renal Calculi
Crystal aggregates that originate in the renal collecting ducts but can deposit anywhere in the urine tract are known as urinary calculi. The study of epidemiology • Frequent, with a 15% lifetime incidence • The risk is larger for men than for women (3:1). Types of stones • 75% calcium oxalate. Ammonium phosphate of magnesium (15%) 5% of stones are uric acid
The pathogenesis • Hypercalciuria is linked to calcium stones. The majority of patients have absorptive hypercalciuria, a condition in which the intestines absorbs excessive amounts of calcium. Others suffer from renal hypercalciuria, a condition where the proximal tubule's ability to absorb calcium is compromised. A small percentage of people experience hypercalciuria as a result of hypercalcaemia, which is typically brought on by primary hyperparathyroidism. Infections with organisms like Proteus, which produce the urease enzyme that breaks down urea into ammonia, are a major cause of triple stones.
Ammonia causes the urine to become alkaline and encourages the precipitation of magnesium ammonium phosphate salts. Triple stones have the potential to grow to enormous sizes and develop into branching masses that fill the renal pelvis and calyces (staghorn calculus).
• Patients with hyperuricaemia, such as those with gout, and diseases characterized by fast cell turnover, such as leukemias, may develop uric acid stones. The majority of individuals, however, do not have elevated uric acid excretion in their urine or hyperuricaemia. These people are believed to have a propensity to produce slightly acidic urine, which increases the risk of developing uric acid. Presentation: Big stones usually stay inside the kidney. They could be detected during a checkup for recurrent UTls or haematuria, or they could be asymptomatic.
• Urinary colic can result from smaller stones getting lodged in the ureter. The vesicoureteric junction, pelvic brim, and pelviureteric junction are frequently the sites of impaction. Issues · A superadded infection in a blocked urinary tract or any obstruction inside the tract of a single kidney is a urological emergency requiring rapid intervention. > Complete obstruction of the urinary tract necessitates prompt intervention to remove the stone.
Crystal aggregates that originate in the renal collecting ducts but can deposit anywhere in the urine tract are known as urinary calculi. The study of epidemiology • Frequent, with a 15% lifetime incidence • The risk is larger for men than for women (3:1). Types of stones • 75% calcium oxalate. Ammonium phosphate of magnesium (15%) 5% of stones are uric acid
The pathogenesis • Hypercalciuria is linked to calcium stones. The majority of patients have absorptive hypercalciuria, a condition in which the intestines absorbs excessive amounts of calcium. Others suffer from renal hypercalciuria, a condition where the proximal tubule's ability to absorb calcium is compromised. A small percentage of people experience hypercalciuria as a result of hypercalcaemia, which is typically brought on by primary hyperparathyroidism. Infections with organisms like Proteus, which produce the urease enzyme that breaks down urea into ammonia, are a major cause of triple stones.
Ammonia causes the urine to become alkaline and encourages the precipitation of magnesium ammonium phosphate salts. Triple stones have the potential to grow to enormous sizes and develop into branching masses that fill the renal pelvis and calyces (staghorn calculus).
• Patients with hyperuricaemia, such as those with gout, and diseases characterized by fast cell turnover, such as leukemias, may develop uric acid stones. The majority of individuals, however, do not have elevated uric acid excretion in their urine or hyperuricaemia. These people are believed to have a propensity to produce slightly acidic urine, which increases the risk of developing uric acid. Presentation: Big stones usually stay inside the kidney. They could be detected during a checkup for recurrent UTls or haematuria, or they could be asymptomatic.
• Urinary colic can result from smaller stones getting lodged in the ureter. The vesicoureteric junction, pelvic brim, and pelviureteric junction are frequently the sites of impaction. Issues · A superadded infection in a blocked urinary tract or any obstruction inside the tract of a single kidney is a urological emergency requiring rapid intervention. > Complete obstruction of the urinary tract necessitates prompt intervention to remove the stone.
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Pathology - Obstruction of the urinary tract
Definition: Urinary tract obstruction (obstructive uropathy) refers to a stoppage in the flow of urine at any location inside the urinary system.
Epidemiology • Predominantly observed in older males (attributable to benign prostatic hypertrophy) and pediatric patients (resulting from congenital urinary system defects).
Aetiology • Urolithiasis. • Urothelial neoplasms. • External compression due to abdominal or pelvic masses. • Benign prostatic hyperplasia. • Anomalies of the urinary tract. • Constrictions.
Presentation • Symptoms indicative of blockage (e.g. ureteric colic). • Diminished renal function. • Recurrent urinary tract infections. The specific clinical presentation will depend on the nature of the obstruction—whether it is acute or chronic, affects the upper or lower urinary tract, and whether it is unilateral or bilateral.
Macroscopy • Dilation of the urinary tract occurs above the obstruction, resulting in hydroureter and hydronephrosis. Renal injury is linked to the degradation of renal tissue and the formation of scars.
Complications Obstruction elevates the likelihood of infection, calculi development, and renal impairment (obstructive nephropathy).
Definition: Urinary tract obstruction (obstructive uropathy) refers to a stoppage in the flow of urine at any location inside the urinary system.
Epidemiology • Predominantly observed in older males (attributable to benign prostatic hypertrophy) and pediatric patients (resulting from congenital urinary system defects).
Aetiology • Urolithiasis. • Urothelial neoplasms. • External compression due to abdominal or pelvic masses. • Benign prostatic hyperplasia. • Anomalies of the urinary tract. • Constrictions.
Presentation • Symptoms indicative of blockage (e.g. ureteric colic). • Diminished renal function. • Recurrent urinary tract infections. The specific clinical presentation will depend on the nature of the obstruction—whether it is acute or chronic, affects the upper or lower urinary tract, and whether it is unilateral or bilateral.
Macroscopy • Dilation of the urinary tract occurs above the obstruction, resulting in hydroureter and hydronephrosis. Renal injury is linked to the degradation of renal tissue and the formation of scars.
Complications Obstruction elevates the likelihood of infection, calculi development, and renal impairment (obstructive nephropathy).
