MCQs: Mycetoma (Lung)
1. What is the most common cause of mycetoma in the lungs?
A. Candida albicans
B. Aspergillus fumigatus
C. Zygomycetes species
D. Histoplasma capsulatum
Answer: B. Aspergillus fumigatus
Comment: Aspergillus fumigatus is the most common fungal species responsible for mycetoma (fungal ball) formation in pre-existing pulmonary cavities.
“Pulmonary mycetoma is most commonly caused by colonization of a pre-existing cavity by Aspergillus species, particularly Aspergillus fumigatus.”
Reference: Radiopaedia: Aspergilloma
2. What is the characteristic imaging finding of a mycetoma on chest CT?
A. Tree-in-bud opacities
B. Air crescent sign
C. Honeycombing in the lung bases
D. Ground-glass opacities with nodules
Answer: B. Air crescent sign
Comment: The air crescent sign, also known as the Monod sign, is a classic finding of a mycetoma, where an air gap surrounds the fungal ball within a cavity.
“On CT, the air crescent sign indicates a fungal ball within a pre-existing cavity, surrounded by air.”
Reference: Radiopaedia: Air Crescent Sign
3. Which underlying condition most commonly predisposes to mycetoma formation in the lung?
A. Sarcoidosis
B. Tuberculosis
C. Cavitary lung cancer
D. Pneumatocele
Answer: B. Tuberculosis
Comment: Tuberculosis is the most common predisposing condition for pulmonary mycetoma due to the formation of residual cavities.
“Tuberculosis is the leading cause of cavitary lung disease predisposing to fungal ball formation.”
Reference: PubMed: Pulmonary Mycetoma
4. What is the most common clinical presentation of a patient with a pulmonary mycetoma?
A. Chronic cough with hemoptysis
B. Severe dyspnea with cyanosis
C. Fever and weight loss
D. Recurrent pleural effusions
Answer: A. Chronic cough with hemoptysis
Comment: Hemoptysis, which can range from mild to life-threatening, is the most common symptom of a pulmonary mycetoma.
“Hemoptysis is the hallmark symptom of pulmonary mycetoma and can sometimes be massive and life-threatening.”
Reference: Radiographics: Fungal Infections in the Lung
5. Which imaging modality is most sensitive for diagnosing a mycetoma?
A. Chest X-ray (CXR)
B. High-resolution CT (HRCT)
C. MRI
D. PET-CT
Answer: B. High-resolution CT (HRCT)
Comment: HRCT is the most sensitive imaging modality for diagnosing a mycetoma, allowing visualization of the fungal ball, air crescent sign, and associated cavity changes.
“HRCT is the gold standard for detecting mycetomas, demonstrating clear visualization of the fungal ball and its relationship to the surrounding cavity.”
Reference: Radiopaedia: Aspergilloma
6. What is the definitive treatment for a symptomatic pulmonary mycetoma with recurrent hemoptysis?
A. Antifungal therapy
B. Bronchoscopy with lavage
C. Surgical resection
D. Observation
Answer: C. Surgical resection
Comment: Surgical resection (lobectomy or wedge resection) is the definitive treatment for recurrent hemoptysis or large symptomatic mycetomas.
“Surgery is indicated for patients with significant symptoms or complications such as recurrent massive hemoptysis.”
Reference: PubMed: Mycetoma Surgery
7. What laboratory test is commonly used to confirm the diagnosis of mycetoma due to Aspergillus?
A. Sputum culture
B. Serum galactomannan antigen test
C. Serum IgG antibodies to Aspergillus
D. Fungal PCR testing
Answer: C. Serum IgG antibodies to Aspergillus
Comment: Elevated serum IgG antibodies to Aspergillus confirm exposure and are supportive of a diagnosis of mycetoma in the appropriate clinical context.
“Detection of serum IgG antibodies to Aspergillus is a reliable diagnostic marker in patients with pulmonary mycetoma.”
Reference: Radiopaedia: Aspergillosis
8. Which complication of pulmonary mycetoma is most life-threatening?
A. Pneumothorax
B. Massive hemoptysis
C. Secondary bacterial pneumonia
D. Pulmonary hypertension
Answer: B. Massive hemoptysis
Comment: Massive hemoptysis due to vascular erosion is the most serious complication of pulmonary mycetoma and can be fatal if untreated.
“Pulmonary mycetoma can erode into blood vessels, causing massive hemoptysis, which is the leading cause of mortality.”
Reference: Radiopaedia: Complications of Aspergilloma
9. Which radiologic sign indicates movement of the fungal ball within the cavity on dynamic imaging?
A. Air crescent sign
B. Monod sign
C. Halo sign
D. Meniscus sign
Answer: B. Monod sign
Comment: The Monod sign refers to the movement of the fungal ball within the cavity on dynamic imaging, confirming the diagnosis of mycetoma.
“The Monod sign is diagnostic of pulmonary mycetoma, indicating the mobility of the fungal ball within the cavity.”
Reference: Radiopaedia: Monod Sign
10. Which condition is least likely to result in a predisposing cavity for pulmonary mycetoma?
A. Tuberculosis
B. Sarcoidosis
C. Pneumatocele
D. Interstitial pulmonary fibrosis
Answer: D. Interstitial pulmonary fibrosis
Comment: Interstitial pulmonary fibrosis does not typically form cavitary lesions, unlike tuberculosis, sarcoidosis, or pneumatocele.
“Conditions that result in pre-existing lung cavities, such as tuberculosis or pneumatocele, predispose to mycetoma formation.”
Reference: Radiographics: Fungal Lung Diseases