Respiratory Pathology Practice Questions

Q: A patient presents with respiratory distress and is diagnosed with panacinar emphysema. Which of the following is deficient?

Alpha-1 antitrypsin. **Alpha-1 antitrypsin** * **Alpha-1 antitrypsin (A1AT) deficiency** is a genetic disorder that leads to the development of panacinar emphysema, especially in non-smokers or at a young age [1], [2]. * A1AT protects the lung tissue from destruction by **elastase** released by neutrophils; without it, this enzyme breaks down alveolar walls [1], [2]. *Surfactant* * **Surfactant** is responsible for reducing surface tension in the alveoli, preventing their collapse in the lungs. * A deficiency primarily causes **neonatal respiratory distress syndrome** or adult respiratory distress syndrome, not predominantly emphysema. *Albumin* * **Albumin** is a primary protein in plasma that maintains oncotic pressure and transports various substances in the blood. * A deficiency in albumin (e.g., in liver disease or malnutrition) typically leads to **edema** and impaired drug transport, not emphysema. *Type II pneumocytes* * **Type II pneumocytes** are responsible for producing and secreting surfactant, as well as acting as progenitor cells for Type I pneumocytes. * While abnormalities in these cells can lead to surfactant deficiency, the direct cause of genetic panacinar emphysema is the lack of protection against elastase, not a primary defect in pneumocyte number or function in this context.

Q: A male patient is not responding to oxygen therapy and has been diagnosed with ARDS (Acute Respiratory Distress Syndrome). What is the role of IL-8 in ARDS?

Recruitment of neutrophils. Recruitment of neutrophils - **Interleukin-8 (IL-8)**, also known as **CXCL8**, is a powerful **chemotactic cytokine** that primarily attracts and activates neutrophils [3]. - In **ARDS**, this recruitment leads to an influx of neutrophils into the pulmonary interstitium and alveolar spaces, contributing to inflammation and lung injury [1]. *Endothelial cell activation* - While other **cytokines** and inflammatory mediators can activate **endothelial cells** in ARDS [2], IL-8's primary role is not direct endothelial activation but rather **neutrophil chemotaxis** [3]. - **Endothelial cell activation** leads to increased vascular permeability and leukocyte adherence, which is often a consequence of overall inflammation, not solely IL-8 [4]. *Macrophage activation* - **Macrophages** are activated by various stimuli and other **cytokines**, such as **TNF-alpha** and **IFN-gamma**, as part of the inflammatory response. - While macrophages produce IL-8, its main function is not to activate macrophages themselves but to attract **neutrophils**. *Promote surfactant production* - **Surfactant production** is primarily regulated by **Type II pneumocytes** and is often impaired in ARDS due to damage to these cells [1]. - IL-8 is a **pro-inflammatory cytokine** and plays no direct role in promoting surfactant synthesis; in fact, its inflammatory effects can indirectly worsen surfactant dysfunction. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 681. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 679. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 87-89. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Migration in the tissues toward a chemotactic stimulus, pp. 86-87.

Q: TTF-1 (Thyroid Transcription Factor-1) immunohistochemical marker is most commonly seen in which of the following?

Lung adenocarcinoma. ***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.

Q: TTF-1 is a tumor marker for which of the following?

Small cell carcinoma. ***Small cell carcinoma*** - **Thyroid transcription factor 1 (TTF-1)** is a nuclear transcription protein expressed in lung and thyroid neoplasms - It is positive in **85-90% of small cell lung carcinomas**, making it a key immunohistochemical marker [1] - TTF-1 helps differentiate small cell carcinoma from other neuroendocrine tumors and extrapulmonary small cell carcinomas [1] *Adenocarcinoma* - TTF-1 is also **strongly positive in 75-80% of lung adenocarcinomas** - It is a primary marker for lung adenocarcinoma, often used with **Napsin A** and **Cytokeratin 7 (CK7)** *Thymoma* - Thymomas are neoplasms of the **thymus gland** and typically express **cytokeratins** but **not TTF-1** - Characteristic markers include **CD5**, **CD117**, and epithelial markers *Melanoma* - Melanomas are cancers of **melanocytes** and express melanocytic markers like **S-100**, **HMB-45**, **Melan-A**, and **SOX10** - **TTF-1** is not expressed in melanoma and helps exclude lung primary when evaluating metastatic disease **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 337-338.

Q: A male patient with hemoptysis. On examination, hilar mass was present. The histopathological image is shown below. Immunohistochemistry revealed that the cells were positive for p40. What is the diagnosis?

Squamous cell carcinoma. ***Squamous cell carcinoma*** - **P40 positivity** is a highly specific marker for squamous cell differentiation, making this diagnosis most likely. - The presence of a **hilar mass** in a male, combined with hemoptysis, is characteristic of squamous cell carcinoma, which often arises centrally [1]. [2] *Large cell carcinoma* - This diagnosis is typically made when there is a **lack of differentiation** into squamous, glandular, or neuroendocrine features. - Large cell carcinoma would not show p40 positivity, as it **lacks overt squamous differentiation**. *Adenocarcinoma lung* - **Adenocarcinoma** is characterized by glandular differentiation and would typically be positive for markers like **TTF-1** and **CK7**, not p40. - While adenocarcinomas can present with hemoptysis, a **hilar mass** is more suggestive of squamous cell carcinoma [1]. *Small cell cancer lung* - **Small cell carcinoma** is a neuroendocrine tumor characterized by small cells with scant cytoplasm and high mitotic activity, and it would be positive for neuroendocrine markers like **chromogranin** and **synaptophysin**. - Small cell carcinoma would **not be positive for p40**, which indicates squamous differentiation. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 336-337. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 723-724.

Q: A CT scan shows the 'crazy paving' pattern in both lungs. Which bronchoalveolar lavage finding would confirm pulmonary alveolar proteinosis?

Milky fluid with PAS-positive material. ***Milky fluid with PAS-positive material*** - A **milky, turbid bronchoalveolar lavage (BAL) fluid** is characteristic of **pulmonary alveolar proteinosis (PAP)** due to the accumulation of lipoproteinaceous material [1]. - **Periodic Acid-Schiff (PAS) staining** confirms the presence of this **glycoprotein-rich surfactant material**, which reacts positively [1]. *Hemosiderin-laden macrophages* - These are indicative of **pulmonary hemorrhage**, not PAP. - They are commonly seen in conditions like **Goodpasture syndrome** or **idiopathic pulmonary hemosiderosis**. *Eosinophilia >25%* - Significant **eosinophilia in BAL fluid** is a hallmark of **eosinophilic pneumonia**, a different interstitial lung disease. - It suggests an **allergic or hypersensitivity reaction** in the lungs. *CD4/CD8 ratio >3.5* - An **elevated CD4/CD8 ratio** in BAL fluid is highly suggestive of **sarcoidosis**, a granulomatous inflammatory disease. - This ratio reflects the **lymphocyte population** in the alveoli, not lipoproteinaceous accumulation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 703-705.

Q: Heart failure cells are:-

Pigmented alveolar macrophages. ***Pigmented alveolar macrophages*** - **Heart failure cells** are **alveolar macrophages** that have phagocytosed **hemosiderin** [1], which is derived from extravasated red blood cells. - This occurs in conditions causing **pulmonary congestion** and **hemorrhage**, most notably in chronic left-sided heart failure [2]. *Lipofuscin granules in cardiac cells* - **Lipofuscin** is a "wear-and-tear" pigment that accumulates in various aging cells, including **cardiac myocytes** [3]. - While present in heart cells, **lipofuscin granules** do not represent the classic "heart failure cells" which are found in the lung [3]. *Pigmented cells in pancreas* - **Pigmented cells in the pancreas** are not a recognized pathological entity described as "heart failure cells." - This option is medically irrelevant in the context of heart failure pathophysiology. *Pigmented hepatocytes* - **Pigmented hepatocytes** can be seen in various conditions, such as **hemochromatosis** (iron overload) or certain drug-induced liver injuries. - However, they are not referred to as "heart failure cells," which specifically refers to hemosiderin-laden macrophages in the lungs. **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. 75-76. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 536-537. [3] 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, p. 75.

Question 1

Which among the following has two general phases - first, simple pneumoconiosis and a second phase characterized by progressive massive fibrosis (PMF)?

Accepted Answer

Anthracosis

Answer

Bagassosis

Answer

Byssinosis

Answer

Siderosis

Question 2

A patient presents with respiratory distress and is diagnosed with panacinar emphysema. Which of the following is deficient?

Accepted Answer

Alpha-1 antitrypsin

Answer

Surfactant

Answer

Albumin

Answer

Type II pneumocytes

Question 3

A male patient is not responding to oxygen therapy and has been diagnosed with ARDS (Acute Respiratory Distress Syndrome). What is the role of IL-8 in ARDS?

Accepted Answer

Recruitment of neutrophils

Answer

Endothelial cell activation

Answer

Macrophage activation

Answer

Promote surfactant production

Question 4

TTF-1 (Thyroid Transcription Factor-1) immunohistochemical marker is most commonly seen in which of the following?

Accepted Answer

Lung adenocarcinoma

Answer

Squamous Cell Carcinoma (SCC)

Answer

Large cell lung cancer

Answer

Papillary thyroid carcinoma

Question 5

TTF-1 is a tumor marker for which of the following?

Accepted Answer

Small cell carcinoma

Answer

Adenocarcinoma

Answer

Thymoma

Answer

Melanoma

Question 6

A male patient with hemoptysis. On examination, hilar mass was present. The histopathological image is shown below. Immunohistochemistry revealed that the cells were positive for p40. What is the diagnosis?

Accepted Answer

Squamous cell carcinoma

Answer

Large cell carcinoma

Answer

Adenocarcinoma lung

Answer

Small cell cancer lung

Question 7

A male patient with hemoptysis. On examination, hilar mass was present. The histopathological image is shown below. Immunohistochemistry revealed that the cells were positive for p40. What is the diagnosis?

Accepted Answer

Squamous cell carcinoma

Answer

Adenocarcinoma lung

Answer

Small cell carcinoma

Answer

Large cell carcinoma

Question 8

A 45-year-old man comes to the physician because of a productive cough and dyspnea. He has smoked one pack of cigarettes daily for 15 years. His temperature is 38.8°C (102°F). Physical examination shows decreased breath sounds and dullness on percussion above the right lower lobe. An x-ray of the chest shows a right lower lobe density and a small amount of fluid in the right pleural space. The patient's symptoms improve with antibiotic treatment, but he develops right-sided chest pain one week later. Pulmonary examination shows new scratchy, high-pitched breath sounds on auscultation of the right lobe. Histologic examination of a pleural biopsy specimen is most likely to show which of the following findings?

Accepted Answer

Fibrin-rich infiltrate

Answer

Dense bacterial infiltrate

Answer

Epithelioid infiltrate with central necrosis

Answer

Red blood cell infiltrate

Question 9

A CT scan shows the 'crazy paving' pattern in both lungs. Which bronchoalveolar lavage finding would confirm pulmonary alveolar proteinosis?

Accepted Answer

Milky fluid with PAS-positive material

Answer

Hemosiderin-laden macrophages

Answer

Eosinophilia >25%

Answer

CD4/CD8 ratio >3.5

Question 10

Heart failure cells are:-

Accepted Answer

Pigmented alveolar macrophages

Answer

Lipofuscin granules in cardiac cells

Answer

Pigmented cells in pancreas

Answer

Pigmented hepatocytes

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

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