Findings: Ultrasound evaluation of the uterus demonstrates multiple solid masses within the uterine myometrium with a whirled appearance and of a similar echogenicity to myometrium. Endometrium was thin and displaced by adjacent masses.

Diagnosis: Uterine leiomyosarcoma.

Discussion: Uterine Leiomyosarcomas are rare accounting for 1.3% of uterine malignancies and may arise from a pre-existing uterine leiomyoma. Frequently patients are asymptomatic, although uterine bleeding may occur. Sonographically, the appearance is similar to that of a rapidly growing or degenerating leiomyoma except when there is evidence of local invasion or distant mets. As these have a similar appearance of leiomyomas, differentiating malignant transformation (as is seen in 0.2% of leiomyomas) is difficult and typically not preoperatively diagnosed.

Metastases from leiomyosarcoma to the lung can be seen. As leiomyosarcoma metastases are rare, when investigating the site, the uterus is by far the most common primary tumor site. Thus, pulmonary metastases of this histology are almost exclusively in women.

References:
Rumack CM. Diagnostic Ultrasound, 2nd Edition. Mosby,
St. Louis; 1998:531.

Dahnert W. Radiology Review Manual, 3rd Edition. Williams & Wilkins,
Baltimore; 1996:765.

Fraser R, Parae JA. Synopsis of Diseases of the Chest, 2nd Edition,
W.B. Saunders, Co., Philadelphia; 1994:529.

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