Amyloid tumor of the sacrum. A case report.

The second published case of amyloidoma in the pelvis and sacrum is reported. Fine needle aspiration biopsy revealed multinucleate giant cells, lymphocytes and plasma cells, some atypical. Congo red staining of the cell block and aspirate showed focal, apple-green birefringence consistent with amyloid. The histologic, radiologic and clinical features of this case are discussed, and the cytologic findings in previously reported fine needle aspiration biopsies of amyloidomas are reviewed.