Mesothelioma — RACP Adult Medicine MCQ

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ModerateRespiratoryMesotheliomaRACP Adult Medicine

A 62-year-old man with a history of asbestos exposure 30 years ago presents with progressive dyspnoea and a right-sided pleural effusion. Pleural fluid cytology is negative. CT shows pleural thickening with encasement of the lung. What is the most likely diagnosis?

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Correct answer: E — Mesothelioma

Pleural thickening with encasement in a patient with significant asbestos exposure history is highly suspicious for malignant pleural mesothelioma. Initial cytology is negative in up to 40% of cases. CT-guided pleural biopsy or thoracoscopic biopsy is required for diagnosis. Immunohistochemistry (calretinin positive, CK5/6 positive, CEA negative) helps distinguish mesothelioma from adenocarcinoma. There is a latency period of 20–40 years from asbestos exposure.

Reference: Cancer Council Australia – 2020 – Mesothelioma Guidelines; Safe Work Australia – 2024