Primary Leiomyosarcoma - Bone

The histologic appearance is identical to that of soft tissue leiomyosarcoma. Fascicles of tumor cells fill up the space between bony spicules. Cigar shaped nuclei, atypical nuclear features, and frequent mitoses were seen in this case. Smooth muscle actin, Desmin, Muscle Specific Actin, and Vimentin were positive.