A case of intradermal fasciitis of the scalp

Abstract

Nodular fasciitis represents reactive fibroblastic or myofibroblastic proliferative lesions which may be misdiagnosed as sarcomas due to the rich cellularity, mitotic activity and variant morphologic pattern. It arises in the subcutaneous tissue, skeletal muscles, and fascia. Uncommon clinical and pathological variants of nodular fasciitis, such as intradermal, intravascular, cranial, ossifying, parosteal and proliferative fasciitis, have been described. We present a 23-year-old man with a one year history of a 2 x 1.5 cm sized hard tender nodule on the scalp which is partially depressed at the margin. Histological examination revealed clusters of spindle cells in a myxoid background, chronic inflammatory cells and extravasated red cells in the dermis. Immunohistochemically, the spindle cells showed positivity of vimentin or smooth muscle actin, and negativity of desmin or S-100 protein. The staining results support its myofibroblastic origin. There is no involved bony lesion on the brain computed tomography (CT). Therefore we report a rare case of intradermal fasciitis arising on the scalp.