Spontaneous uterine leiomyosarcoma in a rhesus macaque.
A 12-year-old female Rhesus macaque (Macaca mulatta) presented with a uterine enlargement during physical exam. Exploratory celiotomy revealed an intrauterine mass that extended into the cervix. A cystic lesion surrounded and enveloped the left ovary. Because of numerous adhesions and the size of the mass, the animal was euthanized. Microscopically, the neoplasia showed small to medium-sized spindle-shaped cells which formed bundles. The cells resembled smooth muscle, with elongated nuclei, indistinct nucleoli, and scant to moderate quantities of eosinophilic cytoplasm. Mitotic activity was low (0 to 2 mitotic figures/high-power field). Immunohistochemistry revealed that the cells stained for smooth muscle actin. In light of the biological activity (locally invasive) and immunohistochemical findings, a diagnosis of leiomyosarcoma of the myometrium was made. Grossly and histologically, uterine leiomyosarcoma can resemble uterine leiomyoma. Although uterine leiomyosarcoma represents a small percentage of uterine tumors, it should always be considered as a rule out for uterine leiomyoma (fibroids).
Cook
Anthony L
AL
BIOQUAL, Inc., 2501 Research Boulevard, Rockville, Maryland 20850-3228, USA.
Rogers
Tiffani D
TD
Sowers
Marsha
M
D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D007890:Leiomyosarcoma / Q000378:metabolism / Q000662:veterinary*; D008253:Macaca mulatta; D008992:Monkey Diseases / Q000378:metabolism*; D014594:Uterine Neoplasms / Q000378:metabolism / Q000662:veterinary*