Rare Case of Pulmonary Perivascular Epithelioid Cell Tumor (PEComa) Causing Right Lung Collapse Managed With Bronchial Stenting: A Clinical Challenge.

Pulmonary perivascular epithelioid cell tumor (PEComa) is an extremely uncommon mesenchymal tumor; pulmonary PEComas can present serious difficulties for both diagnosis and treatment. We present the case of a 62-year-old male with a history of unresectable PEComa of the upper back with metastatic progression to the lungs. Despite ongoing sirolimus therapy, the patient experienced significant tumor growth, presenting to the emergency department with respiratory distress, and was found to have a rapidly enlarging pulmonary mass, later referred for bronchial stenting for palliative treatment. Due to the rarity of these tumors, diagnosis often requires a high index of suspicion and relies on histopathologic confirmation, including immunohistochemistry for melanocytic and muscle markers. Imaging alone is insufficient to distinguish PEComas from other pulmonary masses, underscoring the need for tissue diagnosis. Furthermore, the clinical behaviour of pulmonary PEComas is unpredictable; some remain indolent, while others exhibit aggressive metastatic potential. This heterogeneity complicates treatment planning and highlights the need for individualized, multidisciplinary approaches. We highlight the fact that pulmonary PEComa can rapidly progress and can cause significant morbidity. Palliation with bronchial stenting can be a reasonable option.