Respiratory Tract Cytology — MCQs
A 40-year-old man has hemoptysis. CXR shows a coin lesion. Biopsy reveals nests of neuroendocrine cells with salt-and-pepper chromatin. What is the most likely diagnosis?
A 70-year-old smoker presents with dyspnea and weight loss. CXR shows a mass in the right lung. What is the next step?
TTF-1 (Thyroid Transcription Factor-1) immunohistochemical marker is most commonly seen in which of the following?
Screening under RNTCP emphasizes:
Crumpled paper appearance of cells is a feature of-
Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
What is the most common type of tumour of Vermiform Appendix?
This type of endometrial hyperplasia leads to an increased risk of endometrial cancer.
Which of the following stains is NOT used for the detection of fat?
Which of the following is a stain for fat cells?
Respiratory Tract Cytology Indian Medical PG Practice Questions and MCQs
Question 1: A 40-year-old man has hemoptysis. CXR shows a coin lesion. Biopsy reveals nests of neuroendocrine cells with salt-and-pepper chromatin. What is the most likely diagnosis?
- A. Squamous cell carcinoma
- B. Carcinoid tumor (Correct Answer)
- C. Adenocarcinoma
- D. Small cell carcinoma
Explanation: ***Carcinoid tumor*** - **Nests of neuroendocrine cells** with **salt-and-pepper chromatin** are classic histological features of a carcinoid tumor. - While presented as a **coin lesion** (solitary pulmonary nodule) [2], this type of neuroendocrine tumor typically has a more indolent course compared to other lung malignancies. *Squamous cell carcinoma* - Characterized by **keratinization** and **intercellular bridges**, not neuroendocrine differentiation. - Often presents as a **central mass** with cavitation and is strongly associated with smoking [1]. *Adenocarcinoma* - Grows in glandular patterns and produces **mucin**, usually found in the periphery of the lung. - Lacks the neuroendocrine features of salt-and-pepper chromatin or rosette formation. *Small cell carcinoma* - Consists of small, undifferentiated cells with **scant cytoplasm** and **absent nucleoli**, known for rapid growth. - Although also neuroendocrine, it presents with a much more aggressive clinical course and characteristic **oat cell morphology**, distinct from the well-differentiated nests seen in carcinoid.
Question 2: A 70-year-old smoker presents with dyspnea and weight loss. CXR shows a mass in the right lung. What is the next step?
- A. Bronchoscopy
- B. MRI
- C. Sputum cytology
- D. CT-guided biopsy (Correct Answer)
Explanation: ***CT-guided biopsy*** - A definitive diagnosis of a suspected lung mass, especially in a patient with a history of smoking and weight loss, requires **histological confirmation**. [1] - **CT-guided biopsy** is often the most direct and least invasive method to obtain tissue from a peripheral lung mass for pathological examination. [2] *Bronchoscopy* - While useful for diagnosing central airway lesions, **bronchoscopy** may not reach a peripheral lung mass, making tissue sampling difficult or impossible. [3] - It could be considered if the mass were closer to the main bronchi or if the patient had symptoms suggesting endobronchial involvement. [4] *MRI* - **MRI** is not the primary imaging modality for initial evaluation of a lung mass; **CT scans** provide better anatomical detail of the lungs and chest wall. [2] - It might be used for staging purposes, especially for evaluating brain metastases or chest wall invasion, but not for initial diagnosis of the lung mass itself. *Sputum cytology* - **Sputum cytology** has low sensitivity for diagnosing lung cancer, especially for peripheral lesions, as cancer cells may not be exfoliated into the sputum. - A negative result from sputum cytology does not rule out lung cancer, and a more invasive procedure would still be needed for diagnosis.
Question 3: TTF-1 (Thyroid Transcription Factor-1) immunohistochemical marker is most commonly seen in which of the following?
- A. Squamous Cell Carcinoma (SCC)
- B. Lung adenocarcinoma (Correct Answer)
- C. Large cell lung cancer
- D. Papillary thyroid carcinoma
Explanation: ***Lung adenocarcinoma*** - **TTF-1 (Thyroid Transcription Factor-1)** is a nuclear transcription factor that is highly expressed in adenocarcinomas of the lung. Positivity for TTF-1 is a key marker used in the diagnosis of primary lung adenocarcinoma, distinguishing it from other lung cancers and metastatic tumors. - While TTF-1 can also be positive in thyroid follicular and papillary carcinomas, its strong association with **lung adenocarcinoma** makes it a crucial diagnostic marker in this context, especially when differentiating between primary lung tumors and metastases or other lung cancer types. *Squamous Cell Carcinoma (SCC)* - **Squamous cell carcinoma of the lung** is generally **negative for TTF-1**. It typically expresses markers like p40 and CK5/6. - TTF-1 has very low sensitivity and specificity for squamous cell carcinoma, making it a poor choice for identifying this type of lung cancer. *Large cell lung cancer* - **Large cell lung carcinoma** is a diagnosis of exclusion and is typically **negative for TTF-1**, as well as other specific markers for adenocarcinoma or squamous cell carcinoma. - This type of cancer is characterized by large, anaplastic cells that lack features of other specific lung cancer types when viewed under a microscope. *Papillary thyroid carcinoma* - While **papillary thyroid carcinoma** is also **TTF-1 positive**, the question asks for the most common context in which TTF-1 is seen, and TTF-1 is a highly valuable marker for confirming a lung primary in the setting of lung masses. - TTF-1's utility in lung cancer diagnostics is particularly significant for differentiating primary lung adenocarcinomas from metastatic tumors and other lung cancer subtypes.
Question 4: Screening under RNTCP emphasizes:
- A. Sputum microscopy (Correct Answer)
- B. Chest X-ray
- C. PCR
- D. Sputum culture
Explanation: ***Sputum microscopy*** - Under the Revised National Tuberculosis Control Programme (RNTCP), **sputum microscopy** is the cornerstone for screening and diagnosis of **pulmonary tuberculosis** due to its accessibility, cost-effectiveness, and ability to detect infectious cases. - It involves examining **acid-fast bacilli (AFB)** in sputum samples, allowing for prompt initiation of treatment and interruption of transmission. *Chest X-ray* - While a **chest X-ray** can indicate lung abnormalities suggestive of **tuberculosis**, it is not the primary screening tool under RNTCP for initial diagnosis due to its lower specificity and higher cost compared to sputum microscopy. - It is often used as a supportive diagnostic tool or for screening specific populations. *PCR* - **PCR (Polymerase Chain Reaction)** is a highly sensitive and specific molecular diagnostic method for detecting **Mycobacterium tuberculosis DNA**. - However, it is more expensive and requires specialized laboratory equipment, making it less suitable for widespread primary screening in resource-limited settings like those targeted by RNTCP. *Sputum culture* - **Sputum culture** is considered the gold standard for **tuberculosis diagnosis** due to its high sensitivity and ability to perform **drug susceptibility testing**. - However, it is a time-consuming process (2-6 weeks for results) and costly, making it unsuitable for rapid primary screening in the RNTCP program.
Question 5: Crumpled paper appearance of cells is a feature of-
- A. Asbestosis
- B. GVHD
- C. Gaucher disease (Correct Answer)
- D. Wilson's disease
Explanation: ***Gaucher disease*** - The **crumpled paper** or **wrinkled tissue paper** appearance is characteristic of **Gaucher cells**, which are macrophages engorged with **glucocerebroside** [1]. - This accumulation results from a deficiency in the enzyme **glucocerebrosidase**, a hallmark of Gaucher disease [1]. *Asbestosis* - Characterized by the presence of **asbestos bodies** (ferruginous bodies), which are asbestos fibers coated with an iron-protein complex, not cells with crumpled appearance [2]. - This condition involves **pulmonary fibrosis** due to asbestos exposure [2]. *GVHD (Graft-versus-host disease)* - Histologically, GVHD is characterized by **lymphocytic infiltration** and damage to target organs like skin, liver, and GI tract, not by storage cells with a crumpled appearance. - It is an immunological reaction occurring after **allogeneic hematopoietic stem cell transplantation**. *Wilson's disease* - Involves excessive accumulation of **copper** in various tissues, particularly the liver, brain, and cornea. - Diagnosed by markers like low **ceruloplasmin** and high urinary copper, and does not involve cells with a storage-related crumpled appearance. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 162-163. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 698-699.
Question 6: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
- A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
- B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
- C. Statements 1 and 2 are incorrect
- D. Statement 1 is incorrect
Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris
Question 7: What is the most common type of tumour of Vermiform Appendix?
- A. Germ cell tumour
- B. Adenocarcinoma
- C. Papillary cell tumour
- D. Carcinoid tumour (Correct Answer)
Explanation: ***Carcinoid tumour*** - **Carcinoid tumors** (neuroendocrine tumors) are the **most common primary neoplasms of the appendix**, accounting for approximately 30-50% of all appendiceal tumors. [1] - They typically originate from the **enterochromaffin cells** in the appendiceal mucosa and are often discovered incidentally during appendectomy for suspected appendicitis. - Most appendiceal carcinoids are **small (<2 cm), benign, and located at the tip** of the appendix. [1] *Adenocarcinoma* - **Adenocarcinomas** are the second most common primary tumor of the appendix, representing about 10-20% of cases. - These **epithelial malignancies** include mucinous and non-mucinous subtypes and can present with symptoms mimicking acute appendicitis. - Mucinous adenocarcinomas may lead to **pseudomyxoma peritonei** if they rupture. *Germ cell tumour* - **Germ cell tumors** are exceptionally rare in the appendix and more commonly arise from the gonads (testes, ovaries) or midline structures. - These tumors originate from **pluripotent germ cells** and are not a significant consideration for appendiceal neoplasms. *Papillary cell tumour* - This term describes a **morphological growth pattern** (papillary architecture) rather than a specific primary tumor classification. - While some epithelial tumors may exhibit papillary features, this is **not a recognized primary tumor type** of the appendix. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 375-376.
Question 8: This type of endometrial hyperplasia leads to an increased risk of endometrial cancer.
- A. Simple
- B. Atypical (Correct Answer)
- C. Complex
- D. Secretory
Explanation: ***Atypical*** - **Atypical endometrial hyperplasia** shows both glandular architectural abnormalities and features of cellular atypia, such as nuclear pleomorphism and prominent nucleoli [1]. - The presence of cellular atypia is the key differentiator and significantly increases the risk of progression to **endometrial adenocarcinoma**, with up to 30% progressing to cancer [2]. *Simple* - **Simple endometrial hyperplasia** involves an increase in the number of endometrial glands, which retain their normal shape and uniform distribution [1]. - While it represents abnormal proliferation, the risk of progression to **endometrial cancer** is very low (less than 1%) [2]. *Complex* - **Complex endometrial hyperplasia** shows architectural crowding and branching of glands, but without cellular atypia [2]. - The glands are no longer uniformly spaced, creating a more complex pattern, but the individual cells do not show features of malignancy; therefore, the risk of progression to **endometrial cancer** is low (around 3%) [2]. *Secretive* - **Secretory endometrium** is a normal physiological phase of the menstrual cycle, occurring after ovulation under the influence of progesterone. - This term describes the histological appearance of the endometrium, not a type of hyperplasia or a premalignant condition. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Female Genital Tract, pp. 1016-1018. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Female Genital Tract Disease, pp. 473-475.
Question 9: Which of the following stains is NOT used for the detection of fat?
- A. Oil red O
- B. Sudan black B
- C. Sudan III
- D. Congo red (Correct Answer)
Explanation: **Explanation:** The detection of lipids (fats) in histopathology requires specific stains that are more soluble in the lipid itself than in the solvent in which they are prepared. **Why Congo Red is the correct answer:** **Congo red** is the gold standard stain for **Amyloid**, not fat [1]. When viewed under polarized microscopy, amyloid stained with Congo red exhibits a characteristic **apple-green birefringence** [2]. It binds to the beta-pleated sheet structure of amyloid fibrils [2]. **Why the other options are incorrect:** * **Oil Red O:** This is the most commonly used stain for demonstrating neutral lipids and cholesterols in frozen sections. It imparts a bright red/orange color to fat droplets. * **Sudan Black B:** This is a lipophilic stain that stains neutral triglycerides and lipids black. It is also frequently used in hematopathology to differentiate Acute Myeloid Leukemia (AML) from Acute Lymphoblastic Leukemia (ALL), as it stains the phospholipid membranes of azurophilic granules. * **Sudan III:** Similar to Sudan IV and Oil Red O, this is a lysochrome (fat-soluble dye) used to identify triglycerides in sections or fecal fat analysis. **High-Yield Clinical Pearls for NEET-PG:** 1. **Processing Requirement:** To demonstrate fat, one must use **frozen sections** [3]. Routine processing (paraffin embedding) involves alcohols and xylenes which dissolve lipids, leaving behind empty vacuoles. 2. **Osmium Tetroxide:** This is another reagent used for fat; it fixes and stains lipids black, and unlike the others, it can be used in paraffin-embedded tissues. 3. **Amyloid Confirmation:** Remember the "ABCD" of Amyloid: **A**morphous, **B**eta-pleated, **C**ongo red positive, **D**ichroism (Birefringence). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 580-581. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 268-269. [3] 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. 25-26.
Question 10: Which of the following is a stain for fat cells?
- A. PAS
- B. Prussian blue
- C. Sudan IV (Correct Answer)
- D. Alcian blue
Explanation: **Explanation:** **Correct Answer: C. Sudan IV** Sudan IV (and other Sudan dyes like Sudan Black B and Oil Red O) are **lipid-soluble stains** used to demonstrate neutral triglycerides and lipids in tissue sections [1]. The underlying principle is "physical solubility": the dye is more soluble in the lipid droplets than in the solvent (usually alcohol or propylene glycol), causing the fat cells to take up the pigment. *Note:* For lipid staining, **frozen sections** must be used because routine processing (paraffin embedding) involves alcohols and xylene, which dissolve lipids, leaving behind empty vacuoles [1]. **Incorrect Options:** * **A. PAS (Periodic Acid-Schiff):** Primarily used to demonstrate **glycogen**, mucopolysaccharides, and basement membranes. It stains these structures magenta/bright pink. * **B. Prussian Blue (Perl’s Stain):** A histochemical reaction used to detect **ferric iron** (hemosiderin). It is the gold standard for diagnosing conditions like hemochromatosis or sideroblastic anemia. * **C. Alcian Blue:** A stain used to identify **acid mucopolysaccharides** and mucins. It is frequently used to diagnose Barrett's esophagus (goblet cells) and certain connective tissue tumors. **High-Yield Clinical Pearls for NEET-PG:** * **Oil Red O** is the most commonly used stain for fat in current practice as it provides a more intense red color than Sudan IV [1]. * **Sudan Black B** is the most sensitive lipid stain and is also used in hematopathology to differentiate **AML (positive)** from ALL (negative). * **Osmium Tetroxide** is another method for staining fat, which turns lipids black and also acts as a fixative for electron microscopy. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 73-74.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free