Myolipoma of the round ligament: report of a case with a review of the English literature

Tumours consisting of a mixture of mature adipose and smooth muscle tissues, including those designated lipoleiomyomas, fibrolipoleiomyomas and myolipomas, are exceedingly rare, but most often occur in the uterine corpus. We describe here a case of such a tumour arising in the right round ligament of a 44-year-old woman. The tumour, which measured approximately 20×15×10 cm, was well encapsulated and did not involve the intrapelvic organs. Intricate mixtures of adult adipose tissue and bland smooth muscle exhibited no cellular atypia or nuclear mitotic figures, and there was little vascular proliferation. We diagnosed the lesion as a myolipoma of soft tissue with dual differentiation, and have found only 13 cases of this tumour including our own in the English literature. The present tumour is the first reported in the round ligament. Although this tumour is rare, its recognition is important for the avoidance of erroneous diagnoses.