Dermatofibrosarcoma protuberans (DFSP)   is a rare locally aggressive malignant cutaneous soft-tissue sarcoma. DFSP develops in the connective tissue cells in the middle layer of the skin (dermis). Estimates of the overall occurrence of DFSP in the United States are 0.8 to 4.5 cases per million persons per year. In the United States, DFSP accounts for between 1 and 6 percent of all soft tissue sarcomas  and 18 percent of all cutaneous soft tissue sarcomas. In the Surveillance, Epidemiology and End Results (SEER) tumor registry from 1992 through 2004, DFSP was second only to Kaposi sarcoma. Presentation
Dermatofibrosarcoma protuberans begins as a minor firm area of skin most commonly about  to 1 to 5 cm in diameter. It can resemble a bruise, birthmark, or pimple. It is a slow-growing tumor and is usually found on the torso but can occur anywhere on the body. About 90% of DFSPs are low-grade sarcomas. About 10% are mixed, containing a high-grade sarcomatous component (DFSP-FS); therefore, they are considered to be intermediate-grade sarcomas. DFSPs rarely lead to a metastasis (fewer than 5% metastasize), but DFSPs can recur locally. DFSPs most often arise in patients who are in their thirties but this may be due to diagnostic delay. Location
Commonly located on the chest and shoulders, the following is the site distribution of DFPS as was observed in Surveillance, Epidemiology, and End Results (SEER) [1] database between 2000 and 2010.
All cells are positive with pancytokeratin and epithelial membrane antigen; only the luminal cells are positive with CK7; only the basal  cells are positive with CK5/6, p63, S100 protein. CD117 can be positive in either population. The cells are negative with chromogranin, synaptophysin and CK20. Diagnosis
The major diagnosis from which to separate ceruminous adenoma is ceruminous adenocarcinoma, which shows an infiltrative growth, pleomorphism, mitoses, necrosis, and lacks ceroid pigment granules. Other tumors which need to be excluded include a neuroendocrine adenoma of the middle ear (middle ear adenoma), paraganglioma, and endolymphatic sac tumor. Management
The tumors are usually removed in small pieces due to the anatomic confines of the area. Prognosis
Patients treated with complete surgical excision can expect an excellent long term outcome without any problems. Recurrences may be seen in tumors which are incompletely excised. Epidemiology
While there is a wide age range at clinical presentation (12–85 years), most patients come to clinical attention at 55 years (mean). There is no gender difference. References
Further reading
Lester D. R. Thompson; Bruce M. Wenig (2011). Diagnostic Pathology: Head and Neck: Published by Amirsys. Hagerstown, MD: Lippincott Williams & Wilkins. pp. 7:42–45. ISBN 978-1-931884-61-7.