Cytological diagnosis of primary leiomyosarcoma of bone: case report

We report on a case of primary leiomyosarcoma of the bone in a 77-yr-old man. The patient presented with a painful, enlarging mass in the left shoulder of 6 mo duration. Radiography and computed tomography (CT) revealed a large destructive intramedullary lesion of the proximal humerus, with massive extension into the surrounding soft tissues. CT-guided fine-needle aspiration biopsies (FNAB) of both the bony and soft-tissue lesions were performed. Cytological examination showed a neoplastic process composed of spindle cells mixed with pleomorphic cells. The smooth muscle origin of the neoplastic cells was confirmed by immunocytochemical analysis. We describe the cytological features of this rare primary tumor of bone, and consider the differential diagnosis of spindle-cell neoplasms.