A case report of pigmented dermatofibrosarcoma protuberans (Bednar tumor)

ABSTRACT

Bednar tumor was described by Bednar in 1957. The histologic pattern of this tumor shows similar to dermatofibrosarcoma protuberans (DFSP) but melanin pigments are scattered within the tumor, It's rare neoplasm accounting for approximately 1-5% of all case of DFSP. Clinically, this tumor is considered to be intermediated malignancy, because of slow growth and frequent local recurrence and lack of distant metastasis. The majority are located on the trunk and the upper and lower extremities, but extremely rate in the head and neck area. Microscopically, this tumor is characterized by tight storiform spindle cells and long slender cells that admixed with a small population of melanin containing dendritic cells. This dendritic cells are the primary features distinguising this lesion from conventional DFSP. Complete surgical excision and close follow-up case are necessany for this neoplasm because of probable intermediate malignancy. A patient was admitted to Our Department of Oral and Maxillofacial Surgery due to swelling on right parotid area and numbness of the right lower lip on September, 1994, By clinical examinations and C-T finding, we dignosed tentatively as myxoma or pleomorphic adenoma. Surgical excision of this tumor was performed with parotidectomy and mandibular osteotomy under the frozen biopsy. By final microscopic and electromicroscopic examination and immunohistochemical study, this tumor was diagnosed as Bednar tumor. So, we report a case of pigmented DFSP with review of literatures.