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.