Renal Pathology Practice Questions

Q: The NPHP1 gene encodes which of the following proteins?

Nephrocystin. **Explanation:** The correct answer is **Nephrocystin**. The **NPHP1 gene** encodes the protein **Nephrocystin-1**, which is localized to the primary cilia, basal bodies, and tight junctions of renal tubular epithelial cells. Mutations in this gene are the most common cause of **Nephronophthisis (NPHP)**, an autosomal recessive tubulointerstitial cystic kidney disease. NPHP is a "ciliopathy" that leads to tubular atrophy, interstitial fibrosis, and eventual progression to end-stage renal disease (ESRD) in children and adolescents [1]. **Analysis of Incorrect Options:** * **Fibrocystin (Option A):** Encoded by the **PKHD1** gene [1]. Mutations lead to **Autosomal Recessive Polycystic Kidney Disease (ARPKD)**, characterized by fibrocystin deficiency in the primary cilia [1]. * **Polycystin (Option B):** Encoded by **PKD1** (Polycystin-1) and **PKD2** (Polycystin-2). Mutations in these genes cause **Autosomal Dominant Polycystic Kidney Disease (ADPKD)**. * **Podocin (Option D):** Encoded by the **NPHS2** gene. It is a key component of the glomerular slit diaphragm; mutations lead to steroid-resistant **Nephrotic Syndrome** (specifically FSGS). **High-Yield Clinical Pearls for NEET-PG:** * **Nephronophthisis (NPHP):** Unlike ADPKD, the kidneys in NPHP are typically **small to normal-sized** (shrunken) with cysts located primarily at the **corticomedullary junction** [1]. * **Senior-Løken Syndrome:** A high-yield association where NPHP occurs alongside **Retinitis Pigmentosa**. * **Triad of NPHP:** Polyuria/polydipsia (due to concentrating defects), growth retardation, and progressive renal failure [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 952-954.

Q: Which genetic alteration is associated with the chromophobe variant of renal cell carcinoma?

Monosomy of chromosomes 1 and Y (-1, -Y). ### Explanation **Chromophobe Renal Cell Carcinoma (RCC)** is a distinct subtype of renal cancer derived from the intercalated cells of the collecting ducts [1]. Its genetic profile is characterized by **extreme hypodiploidy** rather than specific gene mutations [1]. #### 1. Why Option D is Correct The hallmark of Chromophobe RCC is the **loss of entire chromosomes (monosomy)** [1]. The most frequent losses involve chromosomes **1, 2, 6, 10, 13, 17, 21, and Y**. Among these, the loss of chromosome 1 and the Y chromosome (in males) are classic diagnostic markers. This widespread chromosomal loss helps differentiate it from other RCC subtypes. #### 2. Why Other Options are Incorrect * **Options A & C (VHL gene / 3p deletions):** These are the genetic signatures of **Clear Cell RCC** (the most common subtype). The *VHL* gene is located on the short arm of chromosome 3 (3p25). * **Option B (Trisomy 7 and 17):** These are characteristic of **Papillary RCC**. Unlike Chromophobe RCC (which loses chromosomes), Papillary RCC is defined by the *gain* of chromosomes (trisomies/polysomies). #### 3. NEET-PG High-Yield Pearls * **Morphology:** Look for "plant-like" cells with prominent cell membranes, perinuclear halos, and "raisinoid" (wrinkled) nuclei [1]. * **Staining:** Chromophobe RCC shows diffuse cytoplasmic positivity with **Hale’s Colloidal Iron stain** (unlike other subtypes). * **Prognosis:** It generally carries a better prognosis compared to Clear Cell RCC [1]. * **Birt-Hogg-Dubé Syndrome:** This hereditary condition is specifically associated with an increased risk of Chromophobe RCC and oncocytomas. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 959.

Q: Lipid casts are seen in which of the following conditions?

Nephrotic syndrome. **Explanation:** **Lipid casts** (and oval fat bodies) are a hallmark finding in **Nephrotic Syndrome** [1]. The underlying mechanism involves massive proteinuria, which triggers the liver to increase lipoprotein synthesis (hyperlipidemia). These lipids leak through the damaged glomerular basement membrane (lipiduria). When renal tubular epithelial cells (RTECs) endocytose these filtered lipids, they become "oval fat bodies." When these cells or free lipids are trapped within a matrix of Tamm-Horsfall protein in the distal tubules, they form lipid casts [2]. Under polarized microscopy, these show a characteristic **"Maltese Cross" appearance** due to the presence of cholesterol esters [2]. **Analysis of Incorrect Options:** * **Acute Tubular Necrosis (ATN):** Characterized by **"Muddy brown" granular casts** or epithelial cell casts resulting from the sloughing of necrotic tubular cells. * **Cytomegalic Inclusion Disease:** Typically shows characteristic large intranuclear inclusions (**"Owl’s eye" appearance**) within tubular cells, which may be seen in urine sediment as exfoliated cells, but not as lipid casts. **High-Yield Clinical Pearls for NEET-PG:** * **Hyaline casts:** Seen in dehydration or normal exercise (non-specific). * **Red Blood Cell (RBC) casts:** Pathognomonic for **Glomerulonephritis** (Nephritic syndrome). * **White Blood Cell (WBC) casts:** Indicative of **Pyelonephritis** or Tubulointerstitial nephritis. * **Waxy/Broad casts:** Suggestive of **Chronic Renal Failure** (due to stasis in dilated, atrophic tubules). * **Fatty casts + Maltese Cross = Nephrotic Syndrome.** **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. 527-528. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 531-532.

Q: Bi-Hogg-Dube syndrome is associated with an increased risk of malignancy in which of the following organs?

Kidney. **Explanation:** **Birt-Hogg-Dubé (BHD) Syndrome** is an autosomal dominant genodermatosis caused by a germline mutation in the **FLCN gene** (encoding the protein **Folliculin**), located on chromosome 17p11.2. **Why Kidney is correct:** The hallmark of BHD is the development of multiple, bilateral **Renal Cell Carcinomas (RCC)**. The most characteristic histological subtype associated with BHD is **Chromophobe RCC** or **Oncocytic Hybrid Tumors** (a hybrid of chromophobe RCC and oncocytoma) [1]. However, clear cell and papillary variants can also occur. **Why other options are incorrect:** * **Stomach:** While some hereditary syndromes like Lynch syndrome or Hereditary Diffuse Gastric Cancer (CDH1) involve the stomach, BHD does not have a recognized association with gastric malignancy. * **Lung:** BHD is strongly associated with the lung, but primarily with **benign** manifestations like **pulmonary cysts** and **spontaneous pneumothorax** (due to ruptured blebs), rather than primary lung malignancy. * **Ovaries:** Ovarian cancers are linked to BRCA1/2 or Lynch syndrome, but there is no established link with the FLCN mutation. **Clinical Pearls for NEET-PG:** 1. **Triad of BHD:** * **Cutaneous:** Benign hair follicle tumors (Fibrofolliculomas, Trichodiscomas, and Acrochordons). * **Pulmonary:** Basal lung cysts and spontaneous pneumothorax. * **Renal:** Multiple/bilateral renal tumors (most commonly Chromophobe RCC) [1]. 2. **High-Yield Association:** If a question mentions "Hybrid Oncocytic Tumors," always think of Birt-Hogg-Dubé Syndrome. 3. **Genetics:** FLCN gene mutation (Folliculin) is the definitive molecular marker. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 958-959.

Question 1

Glomerulosclerosis is a characteristic feature of which of the following conditions?

Accepted Answer

Diabetes mellitus

Answer

Hypertension

Answer

Acute glomerulonephritis

Answer

Nephrotic syndrome

Question 2

Effacement of foot processes is pathognomic of which disease?

Accepted Answer

Minimal change disease

Answer

Steroid resistant glomerulonephritis

Answer

Membranous glomerulonephritis

Answer

IgA nephropathy

Question 3

The NPHP1 gene encodes which of the following proteins?

Accepted Answer

Nephrocystin

Answer

Fibrocystin

Answer

Polycystin

Answer

Podocin

Question 4

Goodpasture syndrome is characterized by which of the following?

Accepted Answer

Anti-GBM antibodies

Answer

Crescents in glomeruli

Answer

Pulmonary hemorrhage

Answer

Diffuse alveolar damage

Question 5

Which genetic alteration is associated with the chromophobe variant of renal cell carcinoma?

Accepted Answer

Monosomy of chromosomes 1 and Y (-1, -Y)

Answer

VHL gene mutations

Answer

Trisomy of chromosomes 7 and 17 (+7, +17)

Answer

3p deletions (3p-)

Question 6

Lipid casts are seen in which of the following conditions?

Accepted Answer

Nephrotic syndrome

Answer

Acute tubular necrosis

Answer

Cytomegalic inclusion disease

Answer

None of the above

Question 7

What is the characteristic feature of kidneys in diabetes mellitus?

Accepted Answer

Nodular glomerulosclerosis (Kimmelstiel-Wilson lesions)

Answer

Fibrin cap

Answer

Papillary necrosis

Answer

Diffuse glomerulosclerosis

Question 8

Pulmonary hypoplasia with urinary problems is associated with which of the following conditions?

Accepted Answer

Potter syndrome

Answer

Mobius syndrome

Answer

Patau syndrome

Answer

WAGR syndrome

Question 9

Which of the following genes is associated with the Xp11 translocation variant of renal cell carcinoma?

Accepted Answer

TFE3

Answer

VHL

Answer

MET

Answer

TSC1

Question 10

Bi-Hogg-Dube syndrome is associated with an increased risk of malignancy in which of the following organs?

Accepted Answer

Kidney

Answer

Stomach

Answer

Lung

Answer

Ovaries

Renal Pathology — MCQs

Renal Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?