Giant myofibroma of the orbit in an adult male.

A 47-year-old male with history of schizophrenia developed painful proptosis and vision loss. Computed Tomography revealed a bone-destructive mass with encroachment on the orbit and compression of the right eye. Superolateral orbitotomy and biopsy revealed a lesion composed of a mixture of spindled and epithelioid cells without significant cytologic atypia or mitotic rate. Immunohistochemical stains were positive for vimentin and multifocally for smooth muscle actin, supporting the diagnosis of orbital myofibroma. Although orbital myofibromas typically present during childhood, they may occur in older patients and act as an expanding mass causing compression of adjacent structures.