Black pleural effusion in a patient with EGFR-positive lung adenocarcinoma

A 68-year-old female presented to the emergency department with shortness of breath and right sided pleuritic chest pain. Chest computed tomography (CT) revealed pleural effusion occupying the right hemithorax. Thoracentesis showed a black-coloured pleural effusion. Fine needle biopsy of the pleura and bronchoscopic biopsy revealed lung adenocarcinoma with epidermal growth factor receptor (EGFR) L858R mutation. This case report describes a patient with an extremely rare case of pleural effusion.