A fibrous histiocytoma of intermediate malignancy arisen from the parotid gland.

The light microscopic and immunohistochemical characteristics of a case of fibrous histiocytoma of intermediate malignancy arising from the parotid gland are presented. This neoplasm is rare in this site and must be distinguished from other spindle cell tumors of the parotid gland, particularly those of epithelial and myoepithelial origins. Histologic characteristics similar to those displayed by dermatofibroma and dermatofibrosarcoma protuberans help to differentiate this tumor from other spindle cell tumors. The absence of cytochemical epithelial markers is useful for establishing the diagnosis. This tumor appears to have arisen from mesenchymal elements within the gland.