Cytopathology — MCQs

Cytopathology Indian Medical PG Practice Questions and MCQs

Question 91: A Pap smear from a 30-year-old woman demonstrates protozoal parasites. What are these organisms most likely to be?

A. Cryptosporidium parvum
B. Entamoeba histolytica
C. Giardia lamblia
D. Trichomonas vaginalis (Correct Answer)

Explanation: **Explanation:** **Trichomonas vaginalis** is the most common protozoal parasite identified in a Pap smear [2]. It is a flagellated, pear-shaped protozoan that causes trichomoniasis, a common sexually transmitted infection (STI) [1]. On a Papanicolaou (Pap) stain, they typically appear as faint, pear-shaped, or "teardrop" organisms (15–30 μm) with a characteristic **"dusky" cyanophilic (gray-green)** cytoplasm and a small, eccentric, vesicular nucleus. A key diagnostic feature often seen on smears is the presence of small, red **Leishman granules** in the cytoplasm. **Why other options are incorrect:** * **Cryptosporidium parvum:** This is an intestinal coccidian parasite causing diarrhea, primarily in immunocompromised patients. It is diagnosed via stool examination (Acid-fast staining), not Pap smears. * **Entamoeba histolytica:** While it can rarely cause cutaneous or genital lesions (amoebiasis cutis), it is primarily a colonic parasite. It is not a standard finding in routine cervical cytology. * **Giardia lamblia:** This is a flagellated protozoan found in the small intestine. It causes malabsorption and diarrhea and is identified in stool samples or duodenal aspirates. **High-Yield Clinical Pearls for NEET-PG:** * **Strawberry Cervix:** Colpitis macularis (punctate hemorrhages on the cervix) is the classic clinical sign of Trichomoniasis. * **pH Changes:** Trichomonas infection typically raises the vaginal pH to **>4.5** [2]. * **Cytological "Halo":** Trichomonas infection often causes a characteristic perinuclear halo in squamous cells (mimicking LSIL/HPV), but without the nuclear atypia seen in true koilocytosis. * **Leptothrix:** These long, hair-like bacteria are frequently seen co-existing with Trichomonas in Pap smears. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Female Genital Tract, pp. 996-997. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Female Genital Tract, pp. 1005-1006.

Question 92: What is the term for a swollen degenerating epithelial cell that results from acantholysis?

A. Anitschow cell
B. Tzanck cell (Correct Answer)
C. Ghost cell
D. Prickle cell

Explanation: ### Explanation **Correct Answer: B. Tzanck cell** **Mechanism and Concept:** A **Tzanck cell** is a rounded, degenerating keratinocyte found in the epidermis. It results from **acantholysis**, a process where the intercellular bridges (desmosomes) between squamous epithelial cells are lost [1]. When these connections break, the cells lose their characteristic polygonal shape, detach from one another, and become rounded or "swollen." Cytologically, these cells often exhibit an enlarged nucleus, perinuclear halo, and condensed peripheral cytoplasm. This is a hallmark finding in **Pemphigus vulgaris** and viral infections like **Herpes Simplex (HSV)** and **Varicella-Zoster (VZV)** [1]. **Analysis of Incorrect Options:** * **A. Anitschow cell:** These are "caterpillar cells" (modified macrophages) seen in the heart during **Acute Rheumatic Fever** (Aschoff bodies), not epithelial cells. * **C. Ghost cell:** These are dead cells that retain their cellular outline but have lost their nucleus (karyolysis). They are typically seen in **Coagulative Necrosis** or specific tumors like Pilomatricoma and Craniopharyngioma. * **D. Prickle cell:** This is a normal anatomical term for cells in the *Stratum Spinosum* layer of the skin, named for the "prickly" appearance of their intact desmosomes. They are not degenerating or acantholytic. **High-Yield NEET-PG Pearls:** * **Tzanck Smear:** A rapid bedside diagnostic test where a blister base is scraped to look for these cells. * **Multinucleation:** In viral infections (HSV/VZV), Tzanck cells characteristically show **multinucleation, nuclear molding, and chromatin margination**. * **Pemphigus vs. Pemphigoid:** Tzanck cells are seen in Pemphigus (intraepidermal/acantholytic) but are **absent** in Bullous Pemphigoid (subepidermal/non-acantholytic) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1170-1172.

Question 93: Which brain tumour is characterized by high vascularity?

A. Glioblastoma (Correct Answer)
B. Meningiomas
C. CP angle epidermoid
D. Pituitary adenoma

Explanation: **Explanation:** **Glioblastoma (GBM)**, a Grade 4 astrocytoma, is defined by two hallmark histopathological features: **microvascular proliferation** [1] and **pseudopalisading necrosis**. The tumor cells secrete high levels of Vascular Endothelial Growth Factor (VEGF), leading to the formation of "glomeruloid bodies"—tufts of multilayered, leaky endothelial cells [1]. This intense neo-angiogenesis makes it the most vascular primary brain tumor, often appearing as a ring-enhancing lesion on MRI due to blood-brain barrier breakdown [1]. **Analysis of Incorrect Options:** * **Meningiomas:** While these are highly vascular extra-axial tumors (supplied by the middle meningeal artery), they are not characterized by the aggressive, disorganized neo-angiogenesis seen in GBM. Their hallmark is the whorled pattern and Psammoma bodies [2]. * **CP Angle Epidermoid:** These are "pearly tumors" derived from ectodermal remnants. They are characteristically **avascular** and slow-growing, often presenting with cranial nerve deficits. * **Pituitary Adenoma:** These are benign epithelial tumors. While they arise in a vascular region, they do not exhibit the diagnostic "high vascularity" or endothelial proliferation that defines high-grade gliomas. **High-Yield Clinical Pearls for NEET-PG:** * **Glomeruloid bodies:** A pathognomonic microscopic finding in Glioblastoma [1]. * **Butterfly Glioma:** GBM often crosses the corpus callosum to involve both hemispheres. * **GFAP (Glial Fibrillary Acidic Protein):** The most reliable IHC marker for tumors of glial origin like GBM. * **IDH Status:** The 2021 WHO classification now defines "Glioblastoma, IDH-wildtype" as the standard adult high-grade astrocytoma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1310-1311. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1316-1317.

Question 94: Stem cells are located in which of the following locations in the body?

A. Retina
B. Endometrium
C. Intestine (Correct Answer)
D. Choana

Explanation: **Explanation:** The correct answer is **Intestine (Option C)**. Stem cells are undifferentiated cells capable of self-renewal and differentiation into specialized cell types [1],[3]. In the adult body, they reside in specific microenvironments known as **"stem cell niches."** * **Intestine:** The intestinal epithelium undergoes rapid turnover (every 3–5 days). To maintain this, multipotent stem cells (Lgr5+ cells) are located at the **base of the Crypts of Lieberkühn** [1],[2]. These cells divide to produce transit-amplifying cells that migrate upward to replace the villus epithelium [3]. * **Retina (Option A):** In humans, the retina is considered a non-regenerative tissue. While some research explores Müller glia as potential progenitors, they are not established functional stem cell niches in the same way as the intestinal crypts. * **Endometrium (Option B):** While the endometrium regenerates monthly, the stem cells are specifically located in the **Basalis layer** (stratum basalis). The general term "endometrium" is less precise than "Intestine" in the context of classic stem cell niche questions, as the functionalis layer lacks these cells. * **Choana (Option D):** The choana is an anatomical passage (posterior nares) and does not serve as a recognized primary reservoir for stem cells. **High-Yield Clinical Pearls for NEET-PG:** * **Skin Stem Cells:** Located in the **bulge area** of the hair follicle [1]. * **Corneal Stem Cells:** Located in the **limbus** (junction of cornea and sclera). Deficiency leads to conjunctivalization of the cornea. * **Liver:** Regeneration occurs via compensatory hyperplasia of mature hepatocytes; however, **Oval cells** (located in the Canals of Hering) act as a secondary stem cell reservoir during chronic injury [1]. * **Hematopoietic Stem Cells (HSCs):** Located in the bone marrow niche, identified by the marker **CD34+** [1],[2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 104-105. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 112-113. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 38-39.

Question 95: What is the most common tumor diagnosed in a female patient with tuberous sclerosis?

A. Rhabdomyosarcoma
B. Renal Angiomyolipoma (Correct Answer)
C. Pulmonary lymphangioleiomyomatosis
D. Optic glioma

Explanation: **Explanation:** **Tuberous Sclerosis Complex (TSC)** is an autosomal dominant neurocutaneous syndrome caused by mutations in the **TSC1 (Hamartin)** or **TSC2 (Tuberin)** genes [1], [2]. These proteins normally inhibit the mTOR pathway; their loss leads to the formation of hamartomas across multiple organ systems. **Why Renal Angiomyolipoma is correct:** Renal Angiomyolipoma (AML) is the **most common mesenchymal tumor** associated with Tuberous Sclerosis, occurring in approximately **70-80% of patients** [1]. These tumors are often bilateral, multicentric, and composed of three elements: thick-walled blood vessels, smooth muscle, and adipose tissue [2]. While they are benign, they carry a high risk of spontaneous hemorrhage (Wunderlich syndrome). **Analysis of Incorrect Options:** * **A. Rhabdomyosarcoma:** This is a malignant skeletal muscle tumor. In TSC, the characteristic cardiac tumor is a **Cardiac Rhabdomyoma** (a benign hamartoma), which is the most common fetal/neonatal cardiac tumor but is not a sarcoma [1]. * **C. Pulmonary lymphangioleiomyomatosis (LAM):** This is a significant manifestation of TSC in females, characterized by cystic lung destruction [1]. While highly specific, it is less common (approx. 30-40% of females) than renal AML. * **D. Optic glioma:** This is classically associated with **Neurofibromatosis Type 1 (NF1)**, not Tuberous Sclerosis. TSC is instead associated with **Retinal Astrocytic Hamartomas** (Mulberry lesions) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Vogt’s Triad:** Adenoma sebaceum (facial angiofibromas), seizures, and mental retardation (present in only 30% of cases) [1]. * **Dermatological findings:** Ash-leaf spots (earliest sign), Shagreen patches (connective tissue nevi), and Periungual fibromas (Koenen tumors). * **CNS findings:** Cortical tubers and **Subependymal Giant Cell Astrocytoma (SEGA)** [1]. * **Drug of Choice:** mTOR inhibitors like **Everolimus** or Sirolimus are used to treat SEGA and renal AMLs. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1318-1319. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 957-958.

Question 96: Vaginal cytology for hormonal assessment is best obtained from which location?

A. Posterior wall
B. Anterior wall
C. Lateral wall (Correct Answer)
D. Any wall

Explanation: **Explanation:** In gynecological cytopathology, the site of sample collection is determined by the clinical objective. For **hormonal assessment** (Cytohormonal Evaluation), the **upper third of the lateral vaginal wall** is the ideal site. **Why the Lateral Wall?** The epithelium of the lateral vaginal wall is highly sensitive to circulating steroid hormones (estrogen and progesterone). Unlike the cervix or the posterior fornix, this area is relatively free from inflammatory exudates, cervical mucus, and debris. This ensures that the cells collected (superficial, intermediate, or parabasal) accurately reflect the patient’s hormonal status, allowing for the calculation of the **Maturation Index (MI)**. **Analysis of Incorrect Options:** * **Posterior wall (and Posterior Fornix):** This is the site for the "Pool Sample." While it is excellent for detecting endometrial or ovarian adenocarcinoma cells that gravitate there, it is unsuitable for hormonal studies because the cells are often partially autolyzed or contaminated by vaginal flora and debris. * **Anterior wall:** This site is not standard for hormonal evaluation as it lacks the consistent epithelial thickness and accessibility found in the lateral wall. * **Any wall:** Hormonal assessment requires a standardized site to ensure reproducibility and accuracy; therefore, random sampling is incorrect. **Clinical Pearls for NEET-PG:** * **Maturation Index (MI):** Expressed as a ratio of Parabasal : Intermediate : Superficial cells. * **Estrogen Effect:** Causes maturation into **Superficial cells** (high MI shift to the right). * **Progesterone Effect:** Causes maturation into **Intermediate cells** (shift to the middle). * **Contraindication:** Cytohormonal evaluation cannot be performed in the presence of local infection (e.g., Trichomoniasis or Candidiasis) as inflammation alters the maturation pattern.

Question 97: Which of the following is a marker of bone resorption?

A. Alkaline phosphatase
B. Procollagen 1 N propeptide
C. C-telopeptide (Correct Answer)
D. Osteocalcin

Explanation: ### Explanation Bone remodeling is a continuous process involving a balance between **bone formation** (by osteoblasts) and **bone resorption** (by osteoclasts). [1] Markers of bone turnover are essential for diagnosing and monitoring metabolic bone diseases like osteoporosis and Paget's disease. **Why C-telopeptide (CTX) is correct:** Type I collagen makes up over 90% of the organic bone matrix. [2] During bone resorption, osteoclasts release enzymes that degrade this collagen. **C-telopeptide (CTX)** and **N-telopeptide (NTX)** are specific cross-linked peptides released into the blood and urine during this degradation. Therefore, CTX is a highly sensitive and specific **marker of bone resorption**. **Analysis of Incorrect Options:** * **A. Alkaline Phosphatase (ALP):** Specifically the bone-specific isoenzyme (BALP), this is a marker of **bone formation**. It reflects osteoblast activity. [1] * **B. Procollagen 1 N propeptide (P1NP):** This is released during the synthesis of Type I collagen. It is considered the most sensitive **marker of bone formation** and is recommended for monitoring osteoporosis treatment. * **C. Osteocalcin:** A non-collagenous protein synthesized by osteoblasts; it is a specific **marker of bone formation** and hydroxyapatite binding. **High-Yield Clinical Pearls for NEET-PG:** * **Resorption Markers:** Serum CTX (preferred), Urinary NTX, and Tartrate-resistant acid phosphatase (TRAP 5b). * **Formation Markers:** Serum P1NP (preferred), Bone-specific ALP, and Osteocalcin. * **Gold Standard:** While biopsy is definitive, P1NP and CTX are the "International Osteoporosis Foundation" recommended markers for monitoring therapy response. * **Hydroxyproline:** An older resorption marker, now less used due to lack of specificity (also found in diet and skin). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1182-1184. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 661-662.

Question 98: Arrange the following heme degradation products in the order of their production:

A. Protoporphyrin, Bilirubin, Biliverdin, Urobilinogen
B. Urobilinogen, Biliverdin, Bilirubin, Protoporphyrin
C. Protoporphyrin, Biliverdin, Bilirubin, Urobilinogen (Correct Answer)
D. Urobilinogen, Bilirubin, Biliverdin, Protoporphyrin

Explanation: ### Explanation The degradation of heme is a highly regulated sequential process occurring primarily in the reticuloendothelial system (spleen and liver). **1. Why Option C is Correct:** The metabolic pathway follows this specific sequence: * **Heme to Protoporphyrin:** Heme consists of a protoporphyrin IX ring complexed with iron ($Fe^{2+}$). The degradation begins with the removal of iron. * **Protoporphyrin to Biliverdin:** The enzyme **Heme Oxygenase** breaks the protoporphyrin ring, releasing carbon monoxide and producing **Biliverdin** (a green pigment) [1]. * **Biliverdin to Bilirubin:** The enzyme **Biliverdin Reductase** reduces biliverdin into unconjugated **Bilirubin** (a yellow pigment) [1]. * **Bilirubin to Urobilinogen:** Once bilirubin is conjugated in the liver and excreted into the bile, intestinal bacteria reduce it into **Urobilinogen** [1], [2]. **2. Why Other Options are Incorrect:** * **Options B & D:** These incorrectly place Urobilinogen at the start. Urobilinogen is a distal product formed only after intestinal bacterial action [2]. * **Option A:** This incorrectly swaps the order of Bilirubin and Biliverdin. Biliverdin must be produced first as an intermediate before it can be reduced to Bilirubin [1]. **3. NEET-PG High-Yield Pearls:** * **Rate-limiting step:** Heme Oxygenase is the rate-limiting enzyme in heme catabolism. * **The "CO" Fact:** Heme degradation is the only endogenous source of **Carbon Monoxide** in the human body. * **Color Changes in Bruises:** The transition of a bruise from purple (heme) to green (biliverdin) to yellow (bilirubin) clinically demonstrates this biochemical pathway. * **Excretion:** While most urobilinogen is excreted in feces (as stercobilin), a small portion undergoes enterohepatic circulation and is excreted by the kidneys as **Urobilin** [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 858-860. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 384-385.

Question 99: Which of the following pathological findings does NOT indicate a malignant phyllodes tumor?

A. Liposarcoma
B. Rhabdomyosarcoma
C. Fibrosarcoma (Correct Answer)
D. None of the above

Explanation: In the context of Phyllodes tumors, the distinction between benign, borderline, and malignant grades depends on stromal features (cellularity, atypia, and mitotic rate) [1]. However, the presence of **heterologous stromal elements** (differentiation into tissues not normally found in the breast) is a pathognomonic marker for **Malignant Phyllodes Tumor** [1]. ### Why Fibrosarcoma is the Correct Answer While **Fibrosarcoma** is a malignant proliferation of fibroblasts, it is considered a **homologous** element because fibroblasts are native to the breast stroma. In the WHO classification of breast tumors, a "fibrosarcoma-like" pattern is a common feature of the spindle cell component in malignant phyllodes, but it is not a specific indicator of malignancy in the same way that heterologous elements are. In many standardized pathology assessments, the presence of specific heterologous components is the "gold standard" for upgrading a tumor to malignant. ### Explanation of Incorrect Options * **A. Liposarcoma:** This is a heterologous element. The presence of lipoblasts within the stroma automatically classifies the phyllodes tumor as malignant [1]. * **B. Rhabdomyosarcoma:** This is another heterologous element (skeletal muscle differentiation) [1]. Like liposarcoma, its presence is a definitive diagnostic criterion for a malignant grade. ### NEET-PG High-Yield Pearls * **Phyllodes Tumor (Cystosarcoma Phyllodes):** Characterized by a "leaf-like" growth pattern with increased stromal cellularity compared to fibroadenomas [1]. * **Grading Criteria:** Based on stromal overgrowth, cellular atypia, mitotic count (usually >10/10 HPF for malignant), and infiltrative borders. * **Heterologous Elements:** Liposarcoma, Chondrosarcoma, Osteosarcoma, and Rhabdomyosarcoma are definitive indicators of malignancy [1]. * **Clinical Fact:** Unlike most breast cancers, phyllodes tumors spread via the **hematogenous route** (lungs/bone) rather than lymphatics; hence, axillary lymph node dissection is usually not required [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, p. 1074.

Question 100: What is the maturation index in the mid-secretory phase of the menstrual cycle?

A. 0/95/5
B. 80/20/0
C. 0/70/30 (Correct Answer)
D. 0/95/5

Explanation: **Explanation:** The **Maturation Index (MI)** is a cytohormonal evaluation used to assess the hormonal status of a patient by calculating the percentage of three types of squamous cells in a lateral vaginal wall smear: **Parabasal cells / Intermediate cells / Superficial cells.** **1. Why 0/70/30 is correct:** The **mid-secretory phase** (post-ovulatory) is dominated by **Progesterone**. Progesterone promotes the maturation of squamous epithelium only up to the **intermediate cell layer** [1]. This results in a "shift to the middle," characterized by a high percentage of intermediate cells and a decrease in superficial cells. A typical MI for this phase is approximately 0/70/30, reflecting the progestational effect. **2. Analysis of Incorrect Options:** * **0/95/5 (Options A & D):** This represents a profound Progesterone effect or "Intermediate cell dominance." This is typically seen in **pregnancy** or the late luteal phase, rather than the mid-secretory phase. * **80/20/0 (Option B):** This shows a "shift to the left" with a dominance of **Parabasal cells**. This is characteristic of **Atrophic vaginitis** or the post-menopausal state where estrogen and progesterone levels are very low. **3. NEET-PG High-Yield Pearls:** * **Estrogen Effect:** Causes maturation to the **Superficial cell** layer (e.g., 0/15/85 at ovulation). * **Progesterone Effect:** Causes maturation to the **Intermediate cell** layer (e.g., Pregnancy, Secretory phase) [1]. * **Navicular Cells:** These are boat-shaped intermediate cells filled with glycogen, commonly seen in the smears of pregnant women due to high progesterone. * **Fern Test:** Positive (ferning) in the Estrogen-dominant follicular phase; Negative in the Progesterone-dominant secretory phase [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Female Genital Tract, pp. 1011-1013.

Practice by Chapter

Basic Principles of Cytopathology

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Specimen Collection and Processing

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Gynecologic Cytology

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Respiratory Tract Cytology

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Urinary Tract Cytology

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Effusion Cytology

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Fine Needle Aspiration Cytology

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Gastrointestinal Tract Cytology

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Ancillary Studies in Cytopathology

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Quality Assurance in Cytopathology

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