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Pulmonary KS Biopsy Pitfall — SCE Infectious Diseases MCQ

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HardHIV MedicinePulmonary KS Biopsy PitfallSCE Infectious Diseases

A 35-year-old man with untreated HIV develops Kaposi sarcoma involving the lungs with bilateral pleural effusions. Bronchoscopy shows violaceous mucosal lesions. Pleural fluid is serosanguineous. What is the key diagnostic pitfall with pleural biopsy in pulmonary KS?

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Correct answer: D — KS may not be visible or sampled on transbronchial biopsy as it is submucosal — visual inspection at bronchoscopy is more sensitive than biopsy for pulmonary KS diagnosis

Pulmonary KS has a characteristic bronchoscopic appearance: violaceous or cherry-red flat or slightly raised submucosal lesions, typically at airway bifurcations. However, transbronchial biopsy often yields false-negative results because the lesions are submucosal and the biopsy may sample only overlying normal mucosa. The visual appearance at bronchoscopy combined with the clinical context (advanced HIV, known cutaneous KS, serosanguineous pleural effusions, typical CT findings) is often sufficient for a working diagnosis. HHV-8 detection in BAL fluid can support the diagnosis.

Reference: BHIVA 2022 – HIV-associated malignancy; BTS 2023 – Bronchoscopy