Pulmonary sclerosing pneumocytoma: a case report of a challenging preoperative diagnosis.

Introduction: Pulmonary sclerosing pneumocytoma (PSP), formerly known as sclerosing hemangioma, is a rare tumor that is typically found incidentally and can closely mimic malignancy on imaging and biopsy, making it challenging to distinguish from lung malignancy. Presentation of case: A 67-year-old man presented with an incidental finding of a nodule in the left upper lobe. Chest computed tomography revealed a 2.2-cm, well-circumscribed nodule adjacent to the pulmonary hilum of the upper lobe. Bronchoscopic biopsy suggested adenocarcinoma, and the patient underwent left upper lobectomy with lymph node dissection via posterolateral thoracotomy. Final histopathological findings resulted in a diagnosis of PSP. Discussion: Accurate preoperative diagnosis of PSP is difficult because the tumor contains heterogeneous histologic components, and limited biopsy samples may capture only areas resembling malignancy. As illustrated in this case, preoperative biopsy may lead to misdiagnosis, and complete resection is often required for a definitive diagnosis. Conclusion: This case highlights the diagnostic difficulty of PSP and underscores the importance of considering PSP when evaluating solitary pulmonary nodules. A brief review of the relevant literature is also provided.