Musculoskeletal System

. The fusiform shape of the tumor is due to the fact that the tumor is following the course of the large blood vessels from which it arose.
Leiomyosarcoma of soft tissues of arm

Gross appearance of retroperitoneal leiomyosarcoma, removed in continuity with the spleen. The whorling appearance of the cut surface is characteristic.

Leiomyosarcoma Retroperitoneum

Leiomyosarcoma metastatic to the liver

As with sarcomas in general, leiomyosarcomas have spindle cells but with cigar-shaped nuclei. Several mitoses are seen here, just in this one high power field.
Leiomyosarcoma