Renal Pathology — MCQs

Renal Pathology Indian Medical PG Practice Questions and MCQs

Question 291: Which of the following statements about Renal Cell Carcinoma (Hypernephroma) is false?

A. Originates in the cortex
B. Histologically are usually adenocarcinomas
C. May present with varicocele
D. Is radiosensitive (Correct Answer)

Explanation: **Explanation:** Renal Cell Carcinoma (RCC), historically known as Hypernephroma, is a primary malignancy of the kidney. The correct answer is **D** because RCC is notoriously **radioresistant**. The primary treatment for localized RCC is surgical (nephrectomy), as it does not respond well to conventional radiotherapy or chemotherapy. **Analysis of Options:** * **A. Originates in the cortex:** This is true. RCC arises from the renal tubular epithelium [2]. Clear cell RCC (the most common subtype) specifically originates from the **Proximal Convoluted Tubule (PCT)**, which is located in the cortex. * **B. Histologically are usually adenocarcinomas:** This is true. Since the tumor arises from glandular epithelial structures (the tubules), it is classified as an adenocarcinoma [2]. * **C. May present with varicocele:** This is a classic clinical association. A left-sided varicocele may occur if the tumor invades the left renal vein, obstructing the drainage of the **left testicular vein** (which drains into the renal vein at a right angle) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Hematuria (most common), flank pain, and a palpable mass (seen in <10% of cases). * **Paraneoplastic Syndromes:** RCC is the "Great Mimic." It can produce **Erythropoietin** (Polycythemia), **PTHrP** (Hypercalcemia), **Renin** (Hypertension), and **ACTH** (Cushing’s) [3]. * **Stauffer Syndrome:** Reversible hepatic dysfunction (elevated LFTs) in the absence of liver metastases. * **Genetics:** Associated with **VHL gene** deletion on **Chromosome 3p** [2]. * **Treatment:** Targeted therapies like VEGF inhibitors (Sunitinib) and Tyrosine Kinase Inhibitors are used for metastatic disease due to its radioresistant nature. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 959-961. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 958-959. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 492-493.

Question 292: Which of the following is a feature of septic shock?

A. Acute tubular necrosis (Correct Answer)
B. Acute cortical necrosis
C. Acute glomerulonephritis
D. Acute papillary necrosis

Explanation: **Explanation:** **Acute Tubular Necrosis (ATN)** is the most common cause of acute kidney injury (AKI) in the setting of **septic shock**. The pathophysiology involves a combination of systemic hypotension (leading to renal hypoperfusion) and the release of inflammatory cytokines (TNF-α, IL-1), which cause direct endothelial and tubular cell injury [2]. The renal tubules, particularly the proximal convoluted tubule (PCT) and the thick ascending limb of Henle, have high metabolic demands, making them exquisitely sensitive to the ischemic and toxic insults characteristic of sepsis [1]. **Analysis of Incorrect Options:** * **B. Acute Cortical Necrosis:** This is a much more severe, irreversible form of injury usually associated with catastrophic obstetric complications (e.g., abruptio placentae) or severe DIC. It involves the death of the entire renal cortex rather than just the tubular epithelium. * **C. Acute Glomerulonephritis:** This is typically an immunologically mediated inflammatory process (e.g., Post-streptococcal GN) rather than a hemodynamic or septic complication. * **D. Acute Papillary Necrosis:** While sepsis can be a trigger, this is classically associated with the mnemonic **POSTCARD** (Pyelonephritis, Obstruction, Sickle cell disease, Tuberculosis, Cirrhosis, Analgesics, and Diabetes Mellitus). **Clinical Pearls for NEET-PG:** * **Morphology:** ATN is characterized by "Muddy brown granular casts" in the urine sediment [1]. * **Ischemic vs. Toxic ATN:** Ischemic ATN (seen in shock) typically shows "skip lesions" along the tubule, whereas toxic ATN is more diffuse [1]. * **Reversibility:** Unlike cortical necrosis, ATN is potentially reversible if the underlying cause is treated, as tubular cells can regenerate [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 933-934. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, p. 144.

Question 293: Which of the following is true about light microscopy findings in minimal change disease?

A. Loss of foot processes is seen on electron microscopy
B. Anti-GBM antibodies are seen
C. IgA deposits are seen
D. No significant changes are seen on light microscopy (Correct Answer)

Explanation: **Explanation:** Minimal Change Disease (MCD) is the most common cause of nephrotic syndrome in children [1]. The diagnosis is primarily based on the characteristic findings across three modalities: Light Microscopy (LM), Immunofluorescence (IF), and Electron Microscopy (EM). **Why Option D is Correct:** The name "Minimal Change" is derived from the fact that the glomeruli appear **completely normal or show only "minimal" changes** (such as mild mesangial expansion) under **Light Microscopy** [2]. The tubules may occasionally show lipid accumulation (lipoid nephrosis), but the glomerular architecture remains preserved. **Analysis of Incorrect Options:** * **Option A:** While the loss (effacement) of podocyte foot processes is the hallmark finding of MCD, this is **only visible on Electron Microscopy (EM)**, not Light Microscopy [2]. The question specifically asks for LM findings. * **Option B:** Anti-GBM antibodies are characteristic of **Goodpasture Syndrome**, which presents as Rapidly Progressive Glomerulonephritis (RPGN), not MCD. * **Option C:** IgA deposits in the mesangium are the diagnostic feature of **IgA Nephropathy (Berger’s Disease)**. In MCD, Immunofluorescence is typically negative for all immunoglobulins and complements [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark:** Diffuse effacement of foot processes on **EM** [1]. * **Clinical Presentation:** Sudden onset massive proteinuria (selective for albumin) [2]. * **Treatment:** Highly steroid-responsive (Prednisolone is the drug of choice) [1], [2]. * **Associations:** Hodgkin Lymphoma and NSAID use. * **IF Finding:** Characteristically "Null" (Negative). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 927-928. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 922-923.

Question 294: Flea-bitten kidney is seen in all of the following conditions except:

A. Scleroderma renal crisis
B. Malignant hypertension
C. Hemolytic uremic syndrome
D. Diabetic nephropathy (Correct Answer)

Explanation: **Explanation:** The term **"Flea-bitten kidney"** refers to a gross morphological appearance characterized by multiple, pinpoint subcapsular hemorrhages. These petechiae occur due to the rupture of glomerular capillaries or arterioles under conditions of acute, severe vascular injury or necrotizing inflammation. **Why Diabetic Nephropathy is the correct answer:** Diabetic nephropathy is a **chronic, progressive** condition characterized by basement membrane thickening and mesangial expansion (Kimmelstiel-Wilson nodules) [1]. It results in **hyalinization** (benign nephrosclerosis) rather than acute necrotizing injury. Grossly, the kidneys in diabetes are typically enlarged (early) or symmetrically shrunken with a granular surface, but they do **not** exhibit petechial hemorrhages. **Analysis of Incorrect Options:** * **Malignant Hypertension:** Causes fibrinoid necrosis of arterioles and hyperplastic arteriolitis ("onion-skinning") [2]. The high pressure causes vessel rupture, leading to the classic flea-bitten appearance. * **Scleroderma Renal Crisis:** Presents with sudden onset malignant hypertension and microangiopathic hemolytic anemia, leading to similar necrotizing vascular changes and petechiae [2]. * **Hemolytic Uremic Syndrome (HUS):** A form of Thrombotic Microangiopathy (TMA) where microthrombi lead to capillary wall damage and hemorrhage, manifesting as a flea-bitten kidney [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Other causes of Flea-bitten Kidney:** Post-streptococcal glomerulonephritis (PSGN), Infective Endocarditis (SBE), Polyarteritis Nodosa (PAN), and Wegener’s Granulomatosis. * **Microscopic hallmark of Malignant HTN:** Fibrinoid necrosis and Onion-skin arteriolitis. * **Microscopic hallmark of Diabetes:** Kimmelstiel-Wilson (KW) nodules (nodular glomerulosclerosis) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1121-1122. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 541-542. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 540-541.

Question 295: Post-streptococcal glomerulonephritis is associated with which of the following?

A. Infection of the skin and throat (Correct Answer)
B. Remission induced by antibiotic treatment
C. A cause of chronic renal failure in the majority of children
D. All of the above

Explanation: **Explanation:** **Post-streptococcal glomerulonephritis (PSGN)** is a classic example of a Type III hypersensitivity reaction (immune-complex mediated) [1] that occurs after an infection with **Group A Beta-hemolytic Streptococci (GABHS)**, specifically nephritogenic strains (e.g., Type 12 for throat, Type 49 for skin). 1. **Why Option A is correct:** PSGN typically follows either **Pharyngitis** (throat infection) or **Impetigo** (skin infection/pyoderma) [1]. The latent period differs: 1–2 weeks after pharyngitis and 3–6 weeks after skin infections. 2. **Why Option B is incorrect:** Antibiotics are used to treat the *initial* streptococcal infection and prevent the spread of the bacteria, but they **do not prevent or treat** the glomerulonephritis once the immune complexes have formed. Treatment for PSGN is primarily supportive (managing fluid overload and hypertension). 3. **Why Option C is incorrect:** PSGN has an excellent prognosis in children. More than **95% of children achieve complete recovery**. Only a very small minority (<1%) progress to chronic renal failure or rapidly progressive glomerulonephritis (RPGN). **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** Light microscopy shows "Starry sky" or "Garland" pattern; Electron microscopy shows characteristic **Subepithelial humps** [2]. * **Immunofluorescence:** Granular deposits of IgG and **C3** (Lumpy-bumpy appearance) [2]. * **Serology:** Low serum C3 levels (normalized within 6–8 weeks) and elevated ASO titers (after pharyngitis) or Anti-DNase B (after skin infection). * **Clinical Presentation:** Nephritic syndrome (hematuria/coca-cola colored urine, edema, and hypertension) [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 914-915. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 915.

Question 296: Which of the following statements is NOT true about renal casts?

A. Casts are formed from albumin secreted by the glomeruli. (Correct Answer)
B. Hyaline casts can be found in normal physiological conditions.
C. Broad casts are characteristic of chronic renal failure.
D. Red blood cell casts are indicative of glomerulonephritis.

Explanation: **Explanation:** **1. Why Option A is the correct (False) statement:** The matrix of all urinary casts is not formed from albumin, but from **Tamm-Horsfall protein (THP)**, also known as **uromodulin** [2]. THP is a high-molecular-weight glycoprotein secreted specifically by the epithelial cells of the **thick ascending limb of the Loop of Henle** [2]. While albumin may be trapped within a cast during glomerular disease, it is not the structural building block. Casts form when THP precipitates in the acidic, concentrated environment of the distal tubules [1]. **2. Analysis of other options:** * **Option B:** **Hyaline casts** consist almost entirely of THP. They are non-specific and can be seen in normal individuals following strenuous exercise, dehydration, or fever [1]. * **Option C:** **Broad casts** (also called "Renal Failure Casts") are significantly wider than standard casts. They form in dilated, atrophic tubules and are a hallmark of **Chronic Renal Failure (CRF)** or end-stage renal disease. * **Option D:** **Red Blood Cell (RBC) casts** are pathognomonic for **glomerular bleeding** [1]. Their presence strongly suggests a diagnosis of **Glomerulonephritis** (e.g., Post-streptococcal GN) or vasculitis. **NEET-PG High-Yield Pearls:** * **Waxy Casts:** Indicate extreme stasis of urine flow; seen in chronic renal disease. * **White Blood Cell (WBC) Casts:** Characteristic of **Acute Pyelonephritis** (helps differentiate it from lower UTI/Cystitis). * **Fatty Casts ("Maltese Cross" appearance):** Associated with **Nephrotic Syndrome**. * **Muddy Brown (Granular) Casts:** Highly suggestive of **Acute Tubular Necrosis (ATN)** [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 520-521. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 524-525.

Question 297: All of the cystic diseases of the kidney cause enlargement of the kidney/renomegaly, except:

A. Autosomal dominant polycystic kidney disease (ADPKD)
B. Autosomal recessive polycystic kidney disease (ARPKD)
C. Nephronophthisis (Correct Answer)
D. Multicystic renal dysplasia

Explanation: **Explanation:** In renal pathology, the size of the kidney is a crucial diagnostic clue. While most cystic diseases lead to an increase in renal volume due to the accumulation of fluid-filled cysts, **Nephronophthisis (NPH)** and **Medullary Cystic Kidney Disease (MCKD)** are notable exceptions. **1. Why Nephronophthisis is the correct answer:** Nephronophthisis is a progressive tubulointerstitial disease characterized by **shrunken, small-sized kidneys** [1]. The underlying pathology involves chronic tubulointerstitial nephritis, leading to extensive tubular atrophy and interstitial fibrosis. Although small cysts (1–15 mm) typically form at the corticomedullary junction, they are not numerous or large enough to cause renomegaly [1]. Instead, the progressive fibrosis leads to renal contraction. **2. Why the other options are incorrect:** * **ADPKD:** Characterized by massive, bilateral enlargement of kidneys due to thousands of expanding cysts that replace the parenchyma [2]. Kidneys can reach weights of several kilograms [1], [2]. * **ARPKD:** Typically presents in infancy with bilaterally enlarged, "sponge-like" kidneys [2]. The enlargement is due to the radial dilation of collecting ducts. * **Multicystic Renal Dysplasia:** Usually presents as a large, irregular, unilateral mass in neonates, consisting of a "bunch of grapes" appearance with no recognizable renal pelvis [3]. **Clinical Pearls for NEET-PG:** * **Nephronophthisis** is the most common genetic cause of End-Stage Renal Disease (ESRD) in children and young adults [1]. * **Key Triad of NPH:** Polyuria/polydipsia, growth retardation, and progressive renal failure with **normal blood pressure** (until late stages). * **High-Yield Distinction:** ADPKD/ARPKD = Large kidneys; NPH/MCKD = Small, shrunken kidneys. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 950-954. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 544-545. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 950-951.

Question 298: Polycystic kidneys can be associated with which of the following complications?

A. Cysts in the liver and lungs
B. Coarctation of the aorta (Correct Answer)
C. Berry aneurysms
D. All of the above

Explanation: This question focuses on the extrarenal manifestations of **Autosomal Dominant Polycystic Kidney Disease (ADPKD)**, a high-yield topic for NEET-PG. [1] ### **Explanation of the Correct Answer** While ADPKD is primarily a renal disorder, it is a systemic condition affecting connective tissues and smooth muscle cells. **Coarctation of the aorta** is a recognized cardiovascular association of ADPKD. The underlying mechanism involves defects in polycystin proteins, which are expressed in the vascular smooth muscle and endothelium, leading to structural abnormalities in large arterial walls. [1] ### **Analysis of Options** * **A. Cysts in the liver and lungs:** While **liver cysts** (Polycystic Liver Disease) are the most common extrarenal manifestation of ADPKD, **lung cysts are not** typically associated with the condition. Pancreatic and splenic cysts are more common. [2] * **C. Berry aneurysms:** These occur in approximately 5-10% of ADPKD patients (specifically in the Circle of Willis). However, in the context of this specific question structure, if "All of the above" is not the intended answer due to the inaccuracy of "lung cysts" in Option A, Coarctation remains a distinct and classic association. * **D. All of the above:** This is incorrect because lung cysts are not a standard feature of ADPKD. ### **High-Yield Clinical Pearls for NEET-PG** * **Genetics:** Most cases (85%) are due to a mutation in the **PKD1 gene** (Chromosome 16), which codes for Polycystin-1. [1] This version progresses to ESRD faster than PKD2 (Chromosome 4). * **Most Common Extrarenal Site:** The **Liver** (Polycystic Liver Disease). * **Most Common Cause of Death:** Cardiac complications (specifically **Hypertension** and its sequelae), followed by infections. * **Other Associations:** Mitral Valve Prolapse (MVP), diverticulosis, and seminal vesicle cysts. * **Distinction:** Do not confuse ADPKD with **ARPKD** (Autosomal Recessive), which presents in infancy with **Congenital Hepatic Fibrosis** and Potter sequence. [2] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 950-955. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 544-545.

Question 299: What type of nephropathy is characteristically seen in Diabetes Mellitus?

A. Focal
B. Diffuse
C. Nodular (Correct Answer)
D. Crescent

Explanation: **Explanation:** Diabetic Nephropathy is a major microvascular complication of Diabetes Mellitus [1]. While several morphological changes occur in the kidney, **Nodular Glomerulosclerosis (Kimmelstiel-Wilson lesions)** is the most characteristic and pathognomonic feature [1]. 1. **Why Nodular is correct:** These are ovoid or spherical, laminated, hyaline masses situated in the periphery of the glomerulus within the mesangial matrix [1]. They result from long-standing non-enzymatic glycosylation of proteins and increased mesangial matrix production. While diffuse glomerulosclerosis is more common, the **nodular form is specific** to diabetes [1]. 2. **Why other options are incorrect:** * **Diffuse:** Diffuse mesangial sclerosis is actually the *most common* lesion in diabetic nephropathy, but it is not as specific (pathognomonic) as the nodular type [1]. * **Focal:** Focal segmental glomerulosclerosis (FSGS) is a distinct primary podocytopathy or a secondary response to reduced nephron mass, not the hallmark of diabetes. * **Crescent:** Crescent formation is the hallmark of **Rapidly Progressive Glomerulonephritis (RPGN)**, indicating severe glomerular injury with rupture of the capillary loops. **High-Yield NEET-PG Pearls:** * **Earliest Clinical Sign:** Microalbuminuria (30–300 mg/day). * **Earliest Morphological Change:** Thickening of the Glomerular Basement Membrane (GBM) [2]. * **Pathognomonic Lesion:** Kimmelstiel-Wilson (KW) nodules (PAS positive) [1]. * **Vascular Change:** Hyaline arteriolosis affecting **both** afferent and efferent arterioles (highly suggestive of DM). * **Armanni-Ebstein Lesions:** Vacuolation of proximal tubular epithelial cells due to glycogen deposits (seen in uncontrolled hyperglycemia). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1119-1122. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1121.

Question 300: In acute interstitial nephritis, which proteins are typically associated?

A. Amyloid
B. Fibrinogen
C. Vitamin D binding protein
D. Light chains (Correct Answer)

Explanation: **Explanation:** **Acute Interstitial Nephritis (AIN)** is an inflammatory condition affecting the renal interstitium and tubules, most commonly triggered by drugs (NSAIDs, antibiotics), infections, or systemic diseases [1]. **Why Light Chains are the correct answer:** In the context of renal pathology, **monoclonal light chains** (associated with Multiple Myeloma) are a classic cause of tubulointerstitial injury [2]. While they primarily cause "Myeloma Kidney" (cast nephropathy), they can also trigger a direct inflammatory response in the interstitium, leading to **Light Chain-induced Acute Interstitial Nephritis** [2]. The light chains are filtered by the glomerulus and reabsorbed by proximal tubular cells, where they exert direct cytotoxicity and promote the release of pro-inflammatory cytokines, resulting in interstitial edema and leucocytic infiltration. **Analysis of Incorrect Options:** * **A. Amyloid:** While amyloidosis involves protein deposition (AL or AA type), it typically presents as a **glomerular disease** (nephrotic syndrome) rather than an acute interstitial inflammatory process [2]. * **B. Fibrinogen:** Fibrinogen/Fibrin deposition is characteristic of **Rapidly Progressive Glomerulonephritis (RPGN)**, where it contributes to "crescent" formation in Bowman’s space, not primary AIN [3]. * **C. Vitamin D binding protein:** This protein is normally filtered and reabsorbed in the tubules; however, it is not a diagnostic or pathological hallmark of AIN. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad of AIN:** Fever, Rash, and Arthralgia (seen in <33% of drug-induced cases) [1]. * **Urinary Findings:** Sterile pyuria and **Eosinophiluria** (Hansel’s stain). * **Drug Triggers:** Remember the "5 P's": **P**ee (Diuretics), **P**ainkillers (NSAIDs), **P**enicillins/Cephalosporins, **P**PIs, and **P**ifampin (Rifampin) [1]. * **Gold Standard Diagnosis:** Renal Biopsy showing interstitial edema and inflammatory infiltrate (T-cells, macrophages, and eosinophils) [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 538-539. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 942-943. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 931-933.

Practice by Chapter

Congenital Anomalies of the Kidney

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Glomerular Diseases

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Tubular and Interstitial Diseases

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Vascular Diseases of the Kidney

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Cystic Diseases of the Kidney

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Urinary Tract Obstruction and Stones

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Renal Tumors

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Kidney in Systemic Diseases

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Renal Transplantation Pathology

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Urinary Tract Infections

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