Dermatofibrosarcoma protuberans post basal cell carcinoma excision: A case report.

INTRODUCTION: Dermatofibrosarcoma protuberans (DFSP) is a rare, malignant, soft tissue neoplasm of the dermis. Tumor recurrence is common following resection, and can be locally devastating if not identified in a timely manner. We report a unique case of this rare tumor. This case poses the question of an association between basal cell carcinoma (BCC) and DFSP, and presents the possible need for increased awareness of DFSP for healthcare providers and patients with a history of non-melanoma skin cancers as well as surgical or burn scars.

PRESENTATION OF CASE: A 77-year-old male with a history of surgical excision of BCC presented with several palpable lesions in the superficial cutaneous tissue of the right anterior abdominal wall. Most of the lesions were consistent with lipoma; however, one lesion near the excision site of the BCC was more solid in consistency. The mass was removed with wide local excision encompassing all layers down to the abdominal fascia. Subsequent pathology findings included CD34 positive spindle cells in a whorled pattern consistent with DFSP. Resection margins were positive and a wide re-excision was performed with margins being negative.

DISCUSSION: DFSP comprises approximately 0.01% of all malignant tumors. There are no known precipitating factors of DFSP, but its presence in surgical and burn scars is not uncommon. An association between DFSP and basal cell carcinoma has been suggested in the literature. Dermatofibroma and rarely DFSP may demonstrate basaloid proliferation of the overlying epidermis with characteristics of BCC. One case reporting coexistent DFSP and BCC located to the ear also suggested an association, but concluded that the finding was likely incidental due to sun exposure. In our case, the lesion's location is less routinely subjected to sun exposure and points more towards a possible association. The mainstay of treatment for local DFSP is wide local excision. Negative margins with the removal of fascia and muscle tissue as necessary is essential and the most significant prognostic factor. Three-dimensional reconstructions of DFSP have shown villous finger like projections of primary tumors, which is believed to be responsible for local recurrence. Recurrence can be devastating, as several cases have demonstrated rapid growth of remaining cells with increased morbidity following further resection.

CONCLUSION: Based on this case and those found in the literature, we believe an association may exist between DFSP and BCC and further study of this association is needed. DFSP is a rare malignancy unknown to many healthcare providers, but in the presence of increased awareness and physician vigilance in surgical resection and follow up, the potential morbidity of DFSP may be prevented.