Cytopathology Practice Questions

Q: Which of the following is a negative stain?

Negrosin. **Explanation:** **1. Why Negrosin is the Correct Answer:** Negrosin (along with India Ink) is a classic example of a **negative stain**. In negative staining, the dye is acidic and carries a negative charge. Since the bacterial cell surface is also negatively charged, the dye is repelled by the cell. Consequently, the background is stained dark, while the organism remains colorless and transparent. This technique is particularly useful for visualizing delicate structures like **capsules**, which do not take up ordinary stains. **2. Analysis of Incorrect Options:** * **Fontana Stain:** This is a silver impregnation stain used primarily to visualize **Spirochetes** (like *Treponema pallidum*) and argentaffin granules. It is not a negative stain. * **ZN (Ziehl-Neelsen) Stain:** This is a **differential stain** (Acid-fast stain) used to identify Mycobacteria [2]. It utilizes carbol fuchsin and heat to penetrate the waxy cell wall. * **Albert Stain:** This is a **special stain** used to demonstrate metachromatic granules (Volutin granules) in *Corynebacterium diphtheriae*. **3. High-Yield Clinical Pearls for NEET-PG:** * **India Ink/Nigrosin:** The most common clinical application is the identification of ***Cryptococcus neoformans*** in CSF (showing a clear halo against a dark background) [1]. * **Capsule Visualization:** Negative staining is the preferred method because heat fixation (required for positive stains) can shrink or destroy the polysaccharide capsule. * **Other Negative Stains:** Eosin and Congo Red can also function as negative stains in specific laboratory contexts. * **Mnemonic:** Remember **"NIC"** for Negative stains: **N**igrosin, **I**ndia Ink, **C**ongo Red. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1274-1275. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 381-382.

Q: Which of the following stains is used for acidic mucin?

Alcian blue. **Explanation:** The correct answer is **Alcian Blue**. **1. Why Alcian Blue is Correct:** Alcian blue is a basic dye containing copper, which gives it its characteristic blue color. It works by forming salt linkages with the anionic (negatively charged) groups of **acidic mucins** (acid mucopolysaccharides and glycosaminoglycans). At a pH of 2.5, it stains both carboxylated and sulfated acidic mucins blue, making it the gold standard for identifying intestinal metaplasia (e.g., Barrett’s esophagus) and certain mucin-secreting tumors. **2. Why Other Options are Incorrect:** * **PAS (Periodic Acid-Schiff):** This stain primarily identifies **neutral mucins**, glycogen, and basement membranes. It reacts with aldehyde groups created by the oxidation of 1,2-glycols. While some acidic mucins may be PAS-positive, it is not specific for them. * **Masson’s Trichrome:** This is a connective tissue stain used to differentiate between **collagen** (stains blue/green) and smooth muscle/epithelium (stains red). * **PTAH (Phosphotungstic Acid Hematoxylin):** This stain is used to demonstrate **striations in skeletal muscle** (rhabdomyosarcoma), fibrin, and glial fibers. **3. High-Yield Clinical Pearls for NEET-PG:** * **Combined PAS-Alcian Blue:** Used to differentiate neutral mucins (magenta) from acidic mucins (blue) in the same section. * **Mucicarmine:** Another specific stain for acidic mucins, particularly useful for identifying *Cryptococcus neoformans* (capsule stains red). * **pH Variation:** At pH 1.0, Alcian blue stains only sulfated mucins; at pH 2.5, it stains both carboxylated and sulfated mucins. * **Colloid Carcinoma:** Often shows abundant Alcian blue-positive extracellular mucin.

Q: A patient with multinodular goiter underwent fine needle aspiration cytology which was suspicious for papillary thyroid carcinoma. What is the percentage of malignancy risk in this patient?

57%. This question tests your knowledge of the **Bethesda System for Reporting Thyroid Cytopathology (BSRTC)**, which is a standardized classification used to estimate the risk of malignancy (ROM) and guide clinical management. In the Bethesda System, the category **"Suspicious for Malignancy" (Category V)** carries a high risk of cancer. According to the updated Bethesda guidelines (2nd and 3rd editions), the risk of malignancy for a "Suspicious" nodule is approximately **50–75%**, with an average value often cited as **57%** (when NIFTP is considered a non-malignant outcome) or higher. Cytologically, this category is used when the aspirate shows some features of malignancy (like nuclear grooves or inclusions in Papillary Thyroid Carcinoma) that are strong but not sufficient for a definitive diagnosis of "Malignant" (Category VI) [1]. Why Other Options are Incorrect: * **A (20%) & C (30%):** These values are too low for Category V. A ROM of **10–30%** is typically associated with **Category III** (Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance - AUS/FLUS). * **D (41%):** This value is more closely associated with **Category IV** (Follicular Neoplasm/Suspicious for Follicular Neoplasm), which generally carries a ROM of **25–40%**. High-Yield Clinical Pearls for NEET-PG: * **Note:** The most common thyroid cancer is Papillary Carcinoma, characterized by Orphan Annie eye nuclei, Psammoma bodies, and nuclear grooves [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1099.

Q: Wilms tumor is associated with all of the following except?

Bilateral polycystic kidney. **Explanation:** Wilms tumor (Nephroblastoma) is the most common primary renal tumor of childhood. It is frequently associated with specific congenital malformations and genetic syndromes [1], but **Bilateral Polycystic Kidney Disease (ADPKD/ARPKD)** is a distinct genetic ciliopathy and is **not** a recognized component of Wilms tumor associations. **Why the other options are associated with Wilms Tumor:** * **Aniridia (Option B):** This is a key feature of the **WAGR Syndrome** (Wilms tumor, Aniridia, Genitourinary anomalies, and intellectual disability/Retardation) [1]. It results from a microdeletion on chromosome 11p13 involving the *WT1* and *PAX6* genes [1]. * **Hemihypertrophy (Option A):** This is a classic feature of **Beckwith-Wiedemann Syndrome (BWS)**, characterized by organomegaly, macroglossia, and hemihypertrophy. BWS is caused by abnormalities in the 11p15.5 region (*WT2* locus). * **Hypertension (Option C):** Up to 25% of patients with Wilms tumor present with hypertension. This occurs due to increased **renin production** by the tumor cells or compression of the renal artery by the tumor mass (Goldblatt kidney mechanism). **High-Yield Clinical Pearls for NEET-PG:** * **Triphasic Morphology:** On histopathology, Wilms tumor shows three components: Blastemal (small blue cells), Stromal (fibrocytic/myxoid), and Epithelial (tubules/glomeruli). * **Denys-Drash Syndrome:** Characterized by Wilms tumor, gonadal dysgenesis, and early-onset nephropathy (diffuse mesangial sclerosis). * **Most Common Presentation:** A large, palpable, asymptomatic abdominal mass in a child (usually 2–5 years old) that does not cross the midline. * **Prognostic Factor:** The presence of **anaplasia** (p53 mutation) is the most important adverse histological prognostic factor. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 487-488.

Question 1

Which of the following is a negative stain?

Accepted Answer

Negrosin

Answer

Fontana

Answer

ZN stain

Answer

Albert stain

Question 2

Which of the following stains is used for acidic mucin?

Accepted Answer

Alcian blue

Answer

PAS

Answer

Masson's trichrome stain

Answer

PTAH

Question 3

Which of the following is homogenously pink staining extracellular fibrillar protein on Congo red staining?

Accepted Answer

Amyloid

Answer

Elastin

Answer

Collagen

Answer

Actin

Question 4

What is the indicated technique for histopathological examination of uterine cancer for mass screening?

Accepted Answer

Exfoliative cytology.

Answer

Brush cytology.

Answer

Fine Needle Aspiration Cytology (FNAC).

Answer

None of the above.

Question 5

A patient with multinodular goiter underwent fine needle aspiration cytology which was suspicious for papillary thyroid carcinoma. What is the percentage of malignancy risk in this patient?

Accepted Answer

57%

Answer

20%

Answer

30%

Answer

41%

Question 6

An intestinal biopsy is most diagnostic in which of the following conditions?

Accepted Answer

Whipple disease

Answer

Celiac disease

Answer

Tropical sprue

Answer

Lactose intolerance

Question 7

A 26-year-old woman experiences the sudden onset of left-sided lower abdominal pain with radiation to the back, pelvis, and thigh. Following a negative test for pregnancy, abdominal radiography shows an enlarged left ovary with multiple calcifications. Laparoscopy reveals adnexal torsion and an ovarian tumor. Ovariectomy is performed. The tumor is most likely?

Accepted Answer

Dermoid cyst.

Answer

Granulosa cell tumor.

Answer

Brenner tumor.

Answer

Serous cystadenoma.

Question 8

Wilms tumor is associated with all of the following except?

Accepted Answer

Bilateral polycystic kidney

Answer

Hemihypertrophy

Answer

Aniridia

Answer

Hypertension

Question 9

A 30-year-old lady presents with features of malabsorption and iron deficiency anemia. Duodenal biopsy reveals complete villous atrophy. Which of the following antibodies is likely to be present?

Accepted Answer

Antiendomysial antibodies

Answer

Anti-goblet cell antibodies

Answer

Anti-saccharomyces cerevisiae antibodies

Answer

Antineutrophil cytoplasmic antibodies

Question 10

A 24-year-old woman is noted to have atypical cells on a Pap smear that are consistent with infection by human papillomavirus (HPV). Which of the following describes the characteristic cytopathic effect caused by infection with HPV?

Accepted Answer

Koilocytosis

Answer

Hyperkeratosis

Answer

Parakeratosis

Answer

Apoptosis

Cytopathology — MCQs

Cytopathology — MCQs

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