Dermatofibrosarcome protuberans (DFSP) is a rare malignant soft tissue tumor characterized by aggressive local béhavioral, high frequency of local recurrence with low metastatic potential. It occurs most often in patients between 20 and 50 years of age, and is preferentially located on the trunk. The standard treatment remains complete surgical excision with wide margins (>3 cm) or Mohs micrographic surgery. We report here a case of DFS unusual by its location on the leg 

Darier-Ferrand dermatofibrosarcoma or dermato fibrosarcome protuberans (DFSP) is a rare cutaneous fibrous tumor, characterized by aggressive local behavior and low metastatic potential.

It was first described in 1924 by Darier and Ferrand. It represents 0.1% of all cancers and 1.8% of all soft tissue sarcomas [1].

The most frequent tumor location is the trunk but rarely the extremities. Herein we are reporting a case of a Darier-Ferrand dermatofibrosarcoma of the leg 

We present the observation of a 45-year-old patient, with no previous medical history, who was referred to us for the management of a protruding mass in the leg that had been evolving for at least 8 years and that had rapidly increased in size and become painful over the past year.  No other systemic or local symptoms were reported. Physical examination revealed a 10-cm, firm, tender mass on the left leg (Figure. 1). There was no evidence of ulceration or bleeding. No adenopathy was found. The lesion was fixed to the overlying skin but mobile in the deeper tissues.

Standard radiographs showed a softs tissus mass without bony involvement.

A punch biopsy was performed, revealing a malignant mesenchymal proliferation, composed of spindle cells with little atypical and low mitotic activity arranged in storiform fascicles. Immuno histo chemistry showed a high expression of CD34 concluding to a dermatofibrosarcoma.

The patient underwent a wide local excision of the mass.

Dermatofibrosarcoma protuberans (DFSP) was first described by Taylor en 1890, followed by Darier and Ferrand en 1924 as dermatofibroma or recurrent progressive fibrosarcoma of the skin, and finally by Hoffmann en 1925 as dermatofibrosarcoma protuberans [2].

It is a rare mesenchymal tumor that belongs to the sarcomas of low grade of malignancy with an aggressive local behavior and has a low metastatic potential. It represents 1.8% of all soft tissue sarcomas and only 0.1% of all cancers with a higher incidence in women and in the black population. It is most often seen in patients between 20 and 50 years of age and localizes preferentially on the trunk and rarely on the extremities [3].

Clinically, it begins as a simple brownish or purplish infiltrated plaque or as a small nipple nodule, usually asymptomatic. It evolves slowly over several years to a large multinodular mass with progressive evolution. There are no known predisposing risk factors for the development of DFSP, but a history of trauma has been noted [4,5].

Histologically, the cells are monomorphic, spindle-shaped, cartwheel-shaped, with few atypia and low mitotic activity. The neoplastic cells often infiltrate the surrounding adipose tissue in a honeycomb pattern. Immunohistochemistry shows diffuse and strong expression of CD34, and loss of expression of other biomarkers such as S100 protein, factor XIIIa, smooth muscle alpha actin and melanin [6].

Differential diagnoses are mainly neurofibroma, dermofibroma, hemangioma, giant cell fibroblastoma, pilomatrixoma and malignant melanoma.

The gold standard treatment for DFSP is wide local excision (WLE), with safety margins ranging from 3 to 5 cm Re-excision is recommended if the surgical margin is positive. Mohs micrographic surgery (MMS) is an alternative to wide local excision [6].

Darier-Ferrand dermatofibrosarcoma is an uncommon recurrent tumor that can occur in sites other than the trunk.

Figure 1: Dermatofibrosarcoma of Darier and Ferrand presented as a mass on the left leg

None of the authors has a conflict of interest to declare.