Recurrent Hydropneumothorax as an Initial Presentation of Malignant Pleural Mesothelioma: Diagnostic Challenges and the Evolving Role of Pleural Fluid Cytology.

Malignant pleural mesothelioma (MPM) is an aggressive pleural malignancy typically associated with asbestos exposure and characterized by a prolonged latency period, often resulting in delayed diagnosis. Although pleural effusion and pleural thickening are common presentations, recurrent hydropneumothorax is an uncommon initial manifestation. Given the broad differential diagnosis of hydropneumothorax, recurrent cases require a thorough clinical and occupational history and appropriate diagnostic evaluation to avoid overlooking an underlying MPM. This case report describes an uncommon initial presentation of MPM and discusses when it is necessary to obtain a tissue sample to confirm the diagnosis.