A Sheep in Wolf's Clothing: Pulmonary Sclerosing Pneumocytoma Mimicking Malignant Neoplasm.

Pulmonary sclerosing pneumocytoma, a rare pulmonary adenoma, is a diagnostic dilemma because of its vague symptoms, ambiguous radiologic features, and varied histopathologic findings, leading to errors in diagnosis and management. We report a case manifesting with a picture of an aggressive malignant neoplasm that postoperatively proved to be benign. This patient presented with a large intrathoracic mass encompassing the pulmonary vessels in the hilum and extending to the posterior mediastinum. After extensive investigations, operability appeared to be a challenge. Complete surgical resection assisted by cardiopulmonary bypass led to a curative outcome. This rare presentation highlights the deceptive nature of pneumocytomas.