Smooth Muscle Tumors of the Visceral Adnexal and Uterine Ligaments and Adnexal Connective Tissue: A Clinicopathologic Study of 67 Cases

The endopelvic fascia is a biomechanical network of supportive tissue that suspends and secures the female reproductive organs to the pelvic sidewall. Several visceral adnexal and uterine ligaments are part of this framework, and we have observed that smooth muscle tumors (SMTs) arising from these structures morphologically resemble gynecologic smooth muscle neoplasms. To determine whether gynecologic smooth muscle tumor criteria for malignancy are valid in these tumors, we evaluated the morphologic features of 67 tumors from 67 patients and correlated our findings with patient outcome. Using current uterine SMT WHO definitions, 57 tumors (85%) were classified as leiomyoma, 2 (3%) as smooth muscle tumor of uncertain malignant potential (STUMP), and 8 (12%) as leiomyosarcoma. Clinical follow-up was available for 88% of patients (range: 1-296 mo, mean: 174 mo, median: 79 mo). Only 1 case of leiomyosarcoma had metastasis at time of presentation, but 6 of 8 (75%) patients eventually died of disease. The other 2 cases of leiomyosarcoma that have not recurred are 11 and 16 mo from initial diagnosis. No cases of STUMP or leiomyoma recurred. On the basis of morphologic features and patient outcome, we believe these tumors distribute into similar categories of leiomyoma, STUMP and leiomyosarcoma, paralleling the biologic potential of uterine SMTs as well as SMTs of other gynecologic sites. We propose use of uterine WHO SMT criteria to classify spindled SMTs that arise in the visceral adnexal and uterine ligaments and adnexal connective tissue.