A 75 year old male with recurrent unilateral pleural effusion and positive ANA.

This case report describes the clinical course and diagnostic challenges arising in a 75 year old man who initially presented with progressive shortness of breath. Imaging revealed a pleural effusion, which was recurrent following thoracentesis. While his initial workup suggested an autoimmune etiology, further diagnostic testing revealed a diagnosis of malignant pleural mesothelioma. Curiously, the patient had no known asbestos exposure, which is classically associated with acquired mesothelioma. There are a small number of similar cases with a possible overlap between positive autoimmune serologies and mesothelioma; however, the underlying pathophysiology remains elusive. It is the authors' goal to contribute this case to the few cases describing such overlap syndromes.