Intramuscular myxomas: a clinicopathologic study with emphasis on surgical management.

Intramuscular myxomas (IMs) are rare myxoid tumors named for their abundance of noncollagenous mucinous stroma. IMs are benign tumors characterized by a paucity of cells, diminished vascularity, and minimal mitotic figures. The objectives of this study were to examine clinicopathologic features of IM and to discuss clinical management of these unusual soft tissue tumors. A 10-year retrospective study at Orlando Regional Medical Center was conducted from May 1993 to May 2003. A case report of a 48-year-old male with a right gluteal mass is presented. Four cases with histologically confirmed diagnosis of intramuscular myxoma were reported. Three patients presented with lesions of the lower extremity and one with an extrafascial IM of the eighth rib. One of the lower extremity cases was shown to be cellular myxoma, a recently characterized subtype of IM. All cases were treated with at least marginal excision of the mass. There have been no known recurrences. Our findings are consistent with described characteristics for IM with respect to anatomic location and gross and microscopic appearance. As it may be unreliable to differentiate IM from malignant myxoid tumors preoperatively, we favor excision with wide margins in the surgical management of these tumors.