Dermatofibrosarcoma Protuberans Arising at a Rho(D) Immune Globulin Injection Site

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue tumor arising in the dermis. It is notorious for high rates of local recurrence despite its low metastatic potential. Although the etiology is unknown, DFSP often is considered to arise within scars and at sites of prior vaccination or trauma. Clinically, DFSP can be highly variable and mimic other soft tissue proliferations. We present a case of recurrent DFSP arising at the site of a Rho(D) immune globulin (RhIg) injection that was administered 7 years prior. We also discuss the diagnostic challenges of DFSP as well as the indolent and locally recurrent nature of the tumor. This case serves to remind dermatologists of the highly variable clinical appearance of DFSP as well as to warn against presumptive diagnoses of lesions that mimic keloids and hypertrophic scars.