Sclerosing pneumocytoma: A rare and easy to miss diagnosis on lung biopsy

Abstract

Sclerosing pneumocytomas (SP) are rare tumours originating from pneumocytes, comprised of two cell types: surface cells and round cells.1 The tumour is heterogeneous and displays four patterns in varying proportions: solid, papillary, sclerotic and angiomatous.1 SP are extremely difficult to diagnose on small samples, such as aspirates and core biopsies,2 and are commonly misdiagnosed as lung adenocarcinoma or carcinoid.3 We present a case of a 60-year-old male who underwent right lower lobe lung nodule core biopsy, which showed a lepidic and acinar growth pattern with surrounding desmoplastic-to-sclerotic stroma and moderate nuclear atypia.