Perivascular Myoma of Myofibromatosis and Myopericytoma‐Type Arising in a Chronic Scar: A Case Report

Abstract

We describe a case of a cutaneous perivascular myoma with features overlapping between the myofibromatosis and the myopericytoma type. The patient is a 58‐year‐old female with a painless plaque‐like and multinodular lesion in the pretibial dermis. She reported repeated trauma to this site, first in her early youth that left an area of hyperpigmentation, and then again at age 40. She had noticed the appearance of nodules in this area 5 years prior to presentation, which had increased in size and number over the last six months. The biopsy showed a biphasic pattern with a myofibromatosis type component composed of spindle cell myoid nodules and more cellular round cell areas. The myopericytoma‐like areas appeared to be infiltrating along vessels. These areas contained aggregates of immature cells arranged concentrically around vascular lumina reminiscent of pericytes. Immunohistochemical stains showed focal positivity for smooth muscle actin. Immunohistochemical and ultrastructural studies have shown these pericyte‐like cells to be of a myoid origin. The reason for the neoplastic proliferation of perivascular myoid cells is presently unknown. The association of trauma and neoplastic transformation of the skin is rare. We report the first case of a cutaneous perivascular myoma arising in a chronic scar.