Respiratory Pathology Practice Questions

Q: Curschmann spirals are characteristic of which of the following airway diseases?

Bronchial asthma. **Explanation:** **Curschmann spirals** are a classic microscopic finding in **Bronchial Asthma**. They represent spiral-shaped mucus plugs formed by the shedding of epithelial cells from the bronchial lining [1]. In asthma, chronic inflammation leads to excessive mucus production and bronchoconstriction; this mucus becomes highly viscous and gets "molded" into the shape of the small airways, appearing as twisted, whorled threads under the microscope [1]. **Analysis of Options:** * **Bronchial Asthma (Correct):** Along with Curschmann spirals, other characteristic findings include **Charcot-Leyden crystals** (formed from eosinophil breakdown) and **Creola bodies** (clusters of exfoliated columnar epithelial cells) [1]. * **Chronic Bronchitis:** While this involves mucus hypersecretion and "blue bloaters" clinical presentation, it is characterized pathologically by an increased **Reid Index** (>0.4), not spiral-shaped mucus plugs. * **Emphysema:** This is defined by the permanent enlargement of airspaces distal to the terminal bronchioles due to alveolar wall destruction. It is a disease of the parenchyma, not primarily one of mucus plugging. * **Atelectasis:** This refers to the collapse of lung tissue. While mucus plugs can *cause* resorptive atelectasis, Curschmann spirals are specifically diagnostic of the underlying asthmatic inflammatory process. **High-Yield Clinical Pearls for NEET-PG:** * **Microscopic Triad of Asthma:** Curschmann spirals, Charcot-Leyden crystals (Galectin-10), and eosinophils. * **Airway Remodeling:** In chronic asthma, look for subepithelial fibrosis (thickening of the basement membrane) and hypertrophy of bronchial smooth muscle. * **Type I Hypersensitivity:** Atopic asthma is mediated by IgE and TH2 cells (releasing IL-4, IL-5, and IL-13) [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 328-329.

Q: Which one of the following immunohistochemical markers is used for the detection of adenocarcinoma of the lung?

Thyroid transcription factor. **Explanation:** **Thyroid Transcription Factor-1 (TTF-1)** is the most specific and widely used immunohistochemical (IHC) marker for identifying **Adenocarcinoma of the lung**. It is a nuclear protein expressed in epithelial cells of the thyroid and the lung (specifically Type II pneumocytes and Clara cells). In the context of a lung mass, TTF-1 positivity helps differentiate primary pulmonary adenocarcinoma from squamous cell carcinoma or metastatic lesions from other sites (except the thyroid). Another highly specific marker often used in conjunction with TTF-1 is **Napsin A**. **Analysis of Incorrect Options:** * **Alpha-fetoprotein (AFP):** This is a marker for **Hepatocellular carcinoma (HCC)** and certain germ cell tumors like **Yolk sac tumors**. * **Glial Fibrillary Acidic Protein (GFAP):** This is an intermediate filament marker for glial cells, used to identify tumors of the central nervous system such as **Astrocytomas** and Ependymomas. * **Progesterone Receptor (PR):** Along with Estrogen Receptor (ER), this is primarily used in the IHC panel for **Breast Cancer** and endometrial carcinomas. **High-Yield Clinical Pearls for NEET-PG:** * **Adenocarcinoma:** Most common lung cancer in non-smokers and women [1]. Markers: **TTF-1 (+), Napsin A (+)**, Cytokeratin 7 (CK7) (+). * **Squamous Cell Carcinoma:** Markers: **p40 (most specific)**, p63, and CK5/6. Squamous differentiation is recognized by keratin or intercellular desmosomes [1]. * **Small Cell Carcinoma:** Neuroendocrine markers: **Synaptophysin, Chromogranin A**, and CD56. * **Mesothelioma:** Markers: **Calretinin**, WT-1, and Cytokeratin 5/6. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 335-337.

Q: A 55-year-old chronic smoker presents with complaints of hemoptysis. Bronchoscopic examination reveals a lesion in the distal trachea growing into the lumen. What is the most probable diagnosis?

Squamous cell carcinoma. **Explanation:** **1. Why Squamous Cell Carcinoma (SCC) is correct:** Squamous cell carcinoma is the most common primary malignancy of the trachea in adults, accounting for approximately 50% of cases. It is strongly associated with a history of **chronic smoking** [1]. These tumors typically present in the distal third of the trachea as exophytic, intraluminal masses that frequently cause hemoptysis and obstructive symptoms . Pathologically, the chronic irritation from smoking leads to squamous metaplasia of the respiratory epithelium, which progresses to dysplasia and eventually invasive carcinoma [1]. **2. Why other options are incorrect:** * **Adenoid Cystic Carcinoma (ACC):** This is the second most common tracheal malignancy. However, unlike SCC, it is **not associated with smoking** and typically has a slower, more indolent growth pattern. It is more likely to be found in younger patients compared to SCC. * **Mucoepidermoid Carcinoma:** This is a rare salivary gland-type tumor of the tracheobronchial tree. While it can occur in the trachea, it is significantly less common than SCC and usually arises from the bronchial submucosal glands. * **Squamous Papilloma:** These are benign epithelial tumors. While they can grow into the lumen, they are less likely to present with significant hemoptysis in a 55-year-old smoker compared to a malignant process. **Clinical Pearls for NEET-PG:** * **Primary Tracheal Tumors:** Rare overall; 90% are malignant in adults. * **Location:** SCC usually involves the distal trachea; ACC often involves the upper third. * **Most common benign tracheal tumor in adults:** Squamous papilloma. * **Most common benign tracheal tumor in children:** Hemangioma. * **High-yield association:** Smoking + Hemoptysis + Central/Tracheal mass = Think Squamous Cell Carcinoma . **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 720-723.

Question 1

Which of the following is NOT a characteristic feature of Kartagener syndrome?

Accepted Answer

Bronchitis

Answer

Sinusitis

Answer

Bronchiectasis

Answer

Infertility

Question 2

All of the following are true about pulmonary embolism except:

Accepted Answer

All cases of pulmonary embolism lead to infarction

Answer

60-80% are asymptomatic

Answer

Most thrombi are formed in deep leg veins

Answer

Embolism may lead to hemorrhagic infarcts in medium arteries

Question 3

A clinical study found that patients who underwent surgical procedures with intubation, mechanical ventilation, and general anesthesia had a higher incidence of pulmonary infections in the two weeks following their surgery compared to patients who were not intubated and did not receive general anesthesia. Anesthesia is most likely to produce this effect via which of the following mechanisms?

Accepted Answer

Decreased ciliary function

Answer

Diminished macrophage activity

Answer

Hypogammaglobulinemia

Answer

Neutropenia

Question 4

A patient presents with a mediastinal mass showing sheets of epithelial cells with an arborizing pattern of reactivity on keratin, along with interspersed lymphoid cells. What is the most probable diagnosis?

Accepted Answer

Thymoma

Answer

Thymic carcinoid

Answer

Primary mediastinal lymphoma

Answer

Non-Hodgkin lymphoma

Question 5

Curschmann spirals are characteristic of which of the following airway diseases?

Accepted Answer

Bronchial asthma

Answer

Chronic bronchitis

Answer

Emphysema

Answer

Atelectasis

Question 6

Which one of the following immunohistochemical markers is used for the detection of adenocarcinoma of the lung?

Accepted Answer

Thyroid transcription factor

Answer

Alpha fetoprotein

Answer

Glial fibrillary acidic protein

Answer

Progesterone receptor

Question 7

A 55-year-old chronic smoker presents with complaints of hemoptysis. Bronchoscopic examination reveals a lesion in the distal trachea growing into the lumen. What is the most probable diagnosis?

Accepted Answer

Squamous cell carcinoma

Answer

Adenoid cystic carcinoma

Answer

Mucoepidermoid carcinoma

Answer

Squamous papilloma

Question 8

A 63-year-old man has had progressively worsening dyspnea over the past 10 years. He has noticed a 5-kg weight loss in the past 2 years. He has a chronic cough with minimal sputum production and no chest pain. On physical examination, he is afebrile and normotensive. A chest radiograph shows extensive interstitial disease. Pulmonary function tests show diminished DLCO, low FVC, and normal FEV1/FVC ratio. Increased exposure to which of the following pollutants is most likely to produce these findings?

Accepted Answer

Silica

Answer

Carbon monoxide

Answer

Ozone

Answer

Tobacco smoke

Question 9

Conglomerate nodules are found in which condition?

Accepted Answer

Silicosis

Answer

Pulmonary lymphangioleiomyomatosis

Answer

Round pneumonia

Answer

Hypersensitivity pneumonitis

Question 10

Basophilic staining of vascular walls due to encrustation by DNA from necrotic tumour cells is seen in which of the following variants of lung cancer?

Accepted Answer

Small cell variant

Answer

Squamous cell variant

Answer

Adenocarcinoma variant

Answer

Large cell variant

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

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