Abstract Introduction Pulmonary sclerosing pneumocytoma (formerly called pulmonary sclerosing hemangioma) is a rare benign slow growing tumor. Here we present a case of Sclerosing pnemocytoma in a middle-aged women discovered incidentally and had accelerated growth. Case Summary A 62-year-old female never smoker with family history of breast cancer found to have incidental 1.6 cm right lower lung nodule on CT scan in March 2022. PET scan showed low grade near blood pool FDG uptake. The nodule was followed with serial CT scan and remained stable until September 2025 and showed increase in size to 2.2 cm with low FDG uptake on repeat PET scan. Patients underwent Robotic bronchoscopy with path results showing diagnosis of Pulmonary sclerosing pneumocytoma. Discussion Pulmonary sclerosing pneumocytoma (PSP) is a rare lung tumor that originates from respiratory epithelium with recent immunohistochemical studies strongly suggesting an origin from respiratory epithelium, particularly type II alveolar pneumocytes. PSP usually occurs in middle-aged women (fifth decade), but cases in young patients have been described, most cases are seen in females (5:1). PSP generally presents as a solitary well-defined mass but Morikawa and et al have published a case of PSP with multiple nodules. Majority of cases are discovered as incidental solitary well-defined nodule on chest imaging. Radiologic characteristics include uniform soft tissue attenuation, smooth margins with size usually less than 5 cm with occasional peripheral calcifications. PSP can show positive FDG uptake on PET scan especially if the size is 2 cm. PSP can have metastatic potential and metastasis to the lymph nodes have been reported. Most of the PSPs can be followed with repeat imaging but increasing size with positive FDG uptake can be challenging. PSP on microscopic examination have distinct pathology, but diagnosis can be challenging with misdiagnoses as another type of tumor due to rarity. Surgical resection is curative and follow imaging is not recommended as evidence suggests a negligible recurrence rate. Conclusion Pulmonary Sclerosing Pneumocytomas are rare benign tumors which can mimic as malignant tumors due to increasing size and FDG uptake on PET scan, physician needs to be aware of these tumor behaviors. This abstract is funded by: None
Premkumar et al. (Fri,) studied this question.