MENINGEAL MYOFIBROBLASTOMA

Myofibroblastoma is a recently described benign mesenchymal tumor. Onl y one case has been reported previously in the CNS. We report a second case of myofibroblastoma arising in the meninges in a 70-year-old wom an who presented with visual changes. The histologic appearance was ch aracterized by alternating areas of spindled and rounded cells separat ed by collagen and amianthoid fibers. Immunostaining demonstrated stro ng vimentin and focal smooth-muscle actin positivity; staining for epi thelial membrane antigen, cytokeratin, S-100, desmin, myosin, glial fi brillary acidic protein, and factor VIII-related antigen was negative. Ultrastructurally, the myofibroblasts had features of both smooth-mus cle cells and fibroblasts. Differentiating the benign myofibroblastoma from more aggressive meningeal sarcomas and meningeal meningiomas is important. The tumor most likely arises from myofibroblasts that proba bly reside in the meninges.