Malignant clear-cell myomelanocytic tumor of broad ligament--a case report.

Clear-cell myomelanocytic tumors (CCMT) of the perivascular epithelioid cell tumor (PEComa) family have been recently reported. We report a case involving a 12-year-old girl. The tumor (9 x 7.5 x 7 cm) was a firm, tan-gray mass with heavily dark pigmentation, massive hemorrhage, and necrosis, and was located in the right broad ligament attached to the right ovary. Histologically, the tumor was composed of polygonal cells exhibiting diffuse hemorrhage, multifocal necroses, and vascular invasion. Most of the tumor cells contained melanin pigments with Fontana-Masson positivity and ultrastructurally suspicious, membrane-bound premelanosomes. Immunohistochemical staining was positive against HMB-45 and focally positive for smooth muscle actin. The tumor recurred in the form of multiple conglomerated masses of the right iliac fossa, with the greatest measuring up to 3.8 cm in dimension, within 1 year. Most CCMT are believed to originate from falciform ligament/ligamentum teres. To the best of our knowledge, this is the second report of a CCMT arising in the broad ligament with typical morphology and contributory ancillary results. Further study for proper subclassification of the PEComa family should be validated, not by anatomic site but by clinical behavior.