Pulmonary sclerosing pneumocytoma: A potential pitfall mimicking lung adenocarcinoma.

Pulmonary sclerosing pneumocytoma (PSP), a rare benign lung tumor of primordial epithelial origin, commonly effects middle-aged Asian females. Diagnosis of this entity is challenging because of the non-specific radiological characteristics that resemble malignancies and its histological heterogeneity. Main differential diagnoses considered are adenocarcinoma lung and carcinoid tumor. In this case report, we discuss our experience of diagnosing a case of pulmonary sclerosing pneumocytoma, which showed increased SUV uptake in PET-CT indicating towards a malignancy and was also misdiagnosed as adenocarcinoma in CT-guided FNAC. The histology showed variable morphological features and there was a differential staining pattern of TTF1 and napsin A in the cells. We have highlighted the differential diagnosis and the challenges faced for diagnosing this benign, rare entity.