Vulvar dermatofibrosarcoma protuberans masquerading as angiomyxoma: A case report and review of 85 cases

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous mesenchymal locally aggressive sarcoma with high recurrence. We report a case of recurrent vulvar DFSP, and a literature review was performed with a PubMed search using the terms "Dermatofibrosarcoma protuberans" and "vulva." Total 85 cases with vulvar DFSP were analyzed for their clinicopathological features among fibrosarcomatous DFSP (FS-DFSP) and non-FS-DFSP. Listless asymptomatic growth had resulted in delay in presentation of 2.3 years. Tumor size was significantly more in FS-DFSP ( P 0.005). Higher mitotic rate is found to have strong association with FS-DFSP ( P 0.0001). FS-DFSP has more recurrences compared with non-FS-DFSP ( P 0.0001). DFSP with FS transformation was more aggressive as there was significant difference in metastasis ( P 0.073, OR 0.18) and mortality ( P 0.210, OR 0.19). To investigate the risk of outcome, 59 cases were included following the exclusion of <6 months follow-up. Age (>50 years) was found to be a risk for metastasis and death from the disease. Tumor size (>5 cm) and mitosis (≥5/10-HPF among non-FS-DFSP) were found to be the risk for the LR. Different histological diagnosis was made initially in 32%, and local excision was performed without margins in 65% of vulvar DFSP because of initial incorrect diagnosis. Therefore, pre-treatment biopsy or re-biopsy should be performed with immunohistochemistry for definitive diagnosis to exclude histologic mimics. The optimal treatment is wide local excision with 3-cm margin or with margin assessment for both primary and recurrent DFSP. As most recurrences occur within the first three years of wide excision in DFSP, regular follow-up visits are advocated.