Musculoskeletal case of the day. Giant cell tumor of the sacrum

Fine-needle aspiration cytologic diagnosis of giant-cell tumor of the sacrum presenting as a rectal mass: A case report

A giant-cell tumor of the sacrum is rare, and poses significant therapeutic and surgical difficulties largely because of its location. Patients usually present with pain in the lower back radiating to one or both lower limbs, with or without neurological deficit. The index case presented with difficulty in defecation, in addition to pain in both lower limbs for 6 mo. The patient was seen to have a rectal mass, and a per-rectal fine-needle-aspiration was performed. The smears showed a cellular aspirate composed of a large number of osteoclastic giant cells, admixed intimately with clusters and a scattered population of mononuclear cells. Mitotic figures were not observed. Although the differential diagnosis of osteoclastic giant cell-containing lesions is broad, the presence of strong cohesiveness between the mononucleated cells and giant cells in cohesive clusters is a very helpful diagnostic feature, and was a prominent finding in the present case.