Dermatofibrosarcoma

Overview
Dermatofibrosarcoma protuberans (DFSP) is a rare tumor. There is only about 1 case per million per year. DFSP is a sarcoma, more precisely a cutaneous soft tissue sarcoma.

Presentation
About 90% of DFSPs are low grade sarcomas. About 10% are mixed; they contain a high-grade sarcomatous component (DFSP-FS); therefore, they are considered to be intermediate-grade sarcomas. All DFSPs rarely lead to a metastasis (fewer than 5% do metastasise), but DFSPs can recur locally. DFSPs most often arise in patients who are in their thirties, but sometimes have been described in children or the elderly.

Treatment
The standard of care for patients with DFSP is surgery. Usually, complete surgical resection with wide margins is performed. The addition of adjuvant radiotherapy (irradiation) improves local control in patients with close or positive margins during the surgery. A special surgical technique, the "Mohs micrographic surgery" (MMS), can be employed in patients with DFSP. MMS is technically possible if the DFSP is in an anatomically confined area. A high probability of cure of DFSP can be attained with MMS as long as the final margins are negative. Patients who have a recurrent DFSP can have further surgery, but the probability of adverse effects of surgery and/or metastasis is increased in these patients.

Imatinib is a so-called "biologic", i.e. a newer medicinal drug. As all medicinal drugs which have a name that ends on -ib, imatinib is a small molecular pathway inhibitor; imatinib inhibits tyrosine kinase. It may be able to induce tumor regression in patients with recurrent DFSP, unresectable DFSP or metastatic DFSP.