[A pink nodule on the face]

We report the case of a 32-year old female patient, with no notable medical history, requiring dermatology consultation for evaluation of a nodule on her right cheek which had evolved over the past 10 years. Clinical examination showed a reddish dermal-based nodule with a smooth surface. The lesion measured 1cm in diameter and was located at the level of the right cheek (A). There was no adenopathy and the remainder of the clinical examination was normal. The patient underwent skin biopsy which showed tumor proliferation composed of fusiform cells with poorly limited eosinophilic cytoplasm and lightly atypical elongated nuclei without mitosis and with mononuclear inflammatory cell infiltrate at the level of the dermis. The epidermis was thinner. Anti-CD68 antibody was positive, while anti-CD34 antibody, PS100 and anti-AML were negative. The diagnosis of benign cellular histiocytofibroma was retained. The patient underwent total resection with a healthy resection margin of 5mm. The patient had a median 2-year follow-up with no recurrences identified. Benign histiocytofibroma mainly occurs in middle-aged women. It more often appears as an erythematous nodular, bluish, brownish or achromique dermal-based little painful but sometimes embarrassing lesion characterized by firm consistency and commonly located at the level of the lower limbs. Racial histiocytofibroma is rarely reported in the literature. Differential diagnosis includes Darier-Ferrand dermatofibrosarcoma, leiomyoma, Kaposi nodule and solitary fibrous tumor of the skin. Histologically, benign cellular histiocytofibroma is composed of pure intradermal disordered proliferation of fusiform cells arranged in bundles or in eddies and circumscribed by lymphocytic inflammatory reaction with presence of foamy histiocytes. The lesion is often highly vascularized with possibile hemorrhagic foci and especially, with angiogenesis images. In a minority of cases, especially in the case of huge histiocytofibromas, the epidermis is thinner and may even ulcerate. The immunohistochemistry shows the expression of CD68 and F XIIIa + positive cells while a lack of CD34, PS100 and Anti-AML expression. It is characterized by a chronic, benign evolution with possible spontaneous regression. The treatment is based on surgical resection.