Renal Pathology Practice Questions

Q: Birt-Hogg-Dubé syndrome is associated with which of the following conditions?

Renal cell carcinoma. **Explanation:** **Birt-Hogg-Dubé (BHD) syndrome** is an autosomal dominant genodermatosis caused by a germline mutation in the **FLCN gene**, which encodes the protein **folliculin**. This syndrome is characterized by a triad of cutaneous, pulmonary, and renal manifestations. 1. **Why Renal Cell Carcinoma (RCC) is correct:** Patients with BHD have a significantly increased risk (up to sevenfold) of developing bilateral and multifocal renal tumors. The most characteristic histological subtype associated with BHD is **Chromophobe RCC** or **Oncocytic hybrid tumors** (a mix of chromophobe and oncocytoma features), though clear cell and papillary RCC can also occur [1]. 2. **Why other options are incorrect:** * **Lung Carcinoma:** While BHD is associated with pulmonary findings like **basal lung cysts** and **spontaneous pneumothorax**, it does not predispose patients to bronchogenic carcinoma. * **Stomach/Ovarian Carcinoma:** There is no established clinical or genetic association between BHD syndrome and an increased risk of gastric or ovarian malignancies. **High-Yield Clinical Pearls for NEET-PG:** * **Cutaneous Triad:** Fibrofolliculomas (most common), trichodiscomas, and acrochordons (skin tags). * **Pulmonary:** Multiple thin-walled lung cysts (usually basal) leading to recurrent spontaneous pneumothorax. * **Genetics:** Mutation in the **FLCN gene** on chromosome **17p11.2**. * **Differential Diagnosis:** Must be distinguished from **Von Hippel-Lindau (VHL)**, which is associated with Clear Cell RCC, and **Hereditary Papillary RCC (MET mutation)** [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 958-959.

Q: Michaelis-Guttmann bodies are characteristic findings in which of the following conditions?

Malacoplakia. **Explanation:** **Malacoplakia** is a chronic inflammatory condition most commonly affecting the urinary bladder, though it can occur in the kidneys. It is characterized by the presence of soft, yellowish, slightly raised mucosal plaques. 1. **Why Malacoplakia is Correct:** The hallmark histological feature of Malacoplakia is the **Michaelis-Guttmann (MG) body**. These are laminated, mineralized (calcified) concretions found within the cytoplasm of large, foamy macrophages known as **von Hansemann cells**. MG bodies form due to the incomplete digestion of bacteria (usually *E. coli*) by lysosomes, leading to the deposition of iron and calcium. They stain positive with **PAS, Von Kossa (for calcium), and Perls' Prussian Blue (for iron).** 2. **Analysis of Incorrect Options:** * **Analgesic Nephropathy:** Characterized by chronic tubulointerstitial nephritis and **renal papillary necrosis** due to long-term intake of NSAIDs or phenacetin. * **Hampton’s Line:** This is a **radiological sign** (not a pathological body) seen on a barium meal study, indicating a benign gastric ulcer. * **Erythroplasia (of Queyrat):** This is a clinical term for **Carcinoma in situ** of the glans penis, appearing as a velvety red plaque. **High-Yield Clinical Pearls for NEET-PG:** * **Organism:** Most commonly associated with ***E. coli*** infection. * **Pathogenesis:** Defect in phagocytic/bactericidal function of macrophages. * **Staining:** Michaelis-Guttmann bodies have a **"targetoid" or "owl's eye"** appearance and are best highlighted by the **Von Kossa stain**. * **Classic Triad:** Chronic UTI + Von Hansemann cells + Michaelis-Guttmann bodies = Malacoplakia.

Q: Which is the commonest site for secondary metastasis in a case of hypernephroma?

Lungs. **Explanation:** **Hypernephroma**, also known as Renal Cell Carcinoma (RCC), is characterized by its unique tendency for early **hematogenous spread** (venous invasion). **1. Why Lungs are the Correct Answer:** The most common site for distant metastasis in RCC is the **Lungs (50-60%)**. This occurs because the tumor cells characteristically invade the renal vein and the inferior vena cava (IVC). From the IVC, the tumor emboli travel directly to the right side of the heart and are then pumped into the pulmonary circulation, where they lodge in the lung parenchyma. On imaging, these often appear as multiple, well-circumscribed nodules known as **"Cannon-ball metastasis."** **2. Analysis of Incorrect Options:** * **Bones:** This is the second most common site (approx. 30-40%). Metastases are typically **osteolytic** (bone-destroying) and often affect the axial skeleton. * **Adrenal:** While RCC can spread to the ipsilateral adrenal gland via direct extension or venous routes, it is less frequent than pulmonary involvement. * **Brain:** Brain metastasis occurs in only about 5% of cases and usually represents a late-stage manifestation of the disease. **3. High-Yield Clinical Pearls for NEET-PG:** * **Route of Spread:** Unlike most carcinomas (which spread via lymphatics), RCC primarily spreads via the **bloodstream**. * **Classic Triad:** Hematuria (most common), flank pain, and a palpable mass (seen in only 10% of patients). * **Histology:** The **Clear Cell** variant is the most common histological subtype. * **Left-sided Varicocele:** A classic physical finding in males if the tumor obstructs the left renal vein, preventing drainage of the left testicular vein.

Q: Basket weave appearance on electron microscopy is classically seen in which of the following conditions?

Alport's syndrome. **Explanation:** **Alport’s Syndrome (Correct Answer):** The "basket-weave" appearance is the pathognomonic electron microscopic (EM) finding for Alport’s syndrome. This condition is caused by mutations in the genes encoding the **α-3, α-4, or α-5 chains of Type IV collagen** (most commonly X-linked) [1]. These mutations lead to a defective glomerular basement membrane (GBM). On EM, the GBM shows irregular thickening and thinning with **longitudinal splitting and splintering of the lamina densa**, creating the characteristic "basket-weave" pattern. **Incorrect Options:** * **RPGN:** Characterized by the presence of **crescents** (proliferation of parietal epithelial cells and monocytes) in Bowman’s space on light microscopy. EM findings vary depending on the underlying cause (e.g., subepithelial humps or linear IgG). * **Henoch-Schönlein Purpura (HSP) & IgA Nephropathy:** These are part of the same disease spectrum. The hallmark finding is **mesangial IgA deposits** on immunofluorescence and mesangial electron-dense deposits on EM. They do not involve the structural splitting of the GBM. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad of Alport’s:** 1. Hereditary nephritis (hematuria/ESRD), 2. Sensorineural deafness, 3. Ocular defects (e.g., Anterior Lenticonus) [1]. * **Thin Basement Membrane Disease (Benign Familial Hematuria):** Also involves Type IV collagen mutations but shows only diffuse thinning of the GBM without the splitting/basket-weaving seen in Alport’s [1]. * **Inheritance:** Most common is **X-linked Dominant** (COL4A5 mutation) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 929-930.

Question 1

Which of the following is NOT a cause for edema in nephritic syndrome?

Accepted Answer

Lymphatic obstruction

Answer

High hydrostatic pressure of plasma

Answer

Increased vascular permeability

Answer

Decreased oncotic pressure of plasma

Question 2

Electron microscopy is visually diagnostic in the renal biopsy study of which condition?

Accepted Answer

Alport syndrome

Answer

Goodpasture's syndrome

Answer

Churg-Strauss syndrome

Answer

Wegener's granulomatosis

Question 3

Birt-Hogg-Dubé syndrome is associated with which of the following conditions?

Accepted Answer

Renal cell carcinoma

Answer

Lung carcinoma

Answer

Stomach carcinoma

Answer

Ovarian carcinoma

Question 4

All of the following decrease in Nephrotic syndrome except-

Accepted Answer

Fibrinogen

Answer

Thyroxin

Answer

Transferrin

Answer

Albumin

Question 5

Michaelis-Guttmann bodies are characteristic findings in which of the following conditions?

Accepted Answer

Malacoplakia

Answer

Analgesic nephropathy

Answer

Hampton's line

Answer

Erythroplasia

Question 6

Which is the commonest site for secondary metastasis in a case of hypernephroma?

Accepted Answer

Lungs

Answer

Adrenal

Answer

Brain

Answer

Bones

Question 7

Which of the following is FALSE regarding Hemolytic Uremic Syndrome (HUS)?

Accepted Answer

Thrombocytopenia is present

Answer

Schistocytes are seen in peripheral blood

Answer

It can be caused by E. coli

Answer

Renal failure is not seen

Question 8

All are causes of immune complex associated membranoproliferative glomerulonephritis in the adult population, EXCEPT?

Accepted Answer

Isoniazid (INH)

Answer

Infective endocarditis

Answer

Systemic lupus erythematosus (SLE)

Answer

Monoclonal gammopathy of undetermined significance

Question 9

Which of the following renal cell carcinomas (RCC) does not exhibit papillary architecture histologically?

Accepted Answer

Succinate dehydrogenase-deficient RCC

Answer

Xp11 translocation carcinoma

Answer

Bellini duct carcinoma

Answer

Papillary carcinoma

Question 10

Basket weave appearance on electron microscopy is classically seen in which of the following conditions?

Accepted Answer

Alport's syndrome

Answer

Rapidly progressive glomerulonephritis (RPGN)

Answer

Henoch-Schonlein purpura (HSP)

Answer

IgA nephropathy

Renal Pathology — MCQs

Renal Pathology — MCQs

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