Granulome annulaire perforant unique avec phénomène d'élimination transfolliculaire

In our observation, the single localization of this lesion raises the problem of differential diagnosis such as cutaneous tuberculosis, atypical mycobacteriosis, skin sarcoidosis, foreign body granuloma, epidermoid carcinoma or perforating dermatitis. The histological examination permitted diagnosis of a perforating granuloma annulare with large epidermic ulceration. The infiltration and destruction of a hair follicle evoked the possible transfollicular elimination of the necrotic material. Other pathologies with the histological aspect of a palisading granuloma were excluded from this context. No associated pathology such as diabetes nor any other favouring factors such as ultraviolet light or insect bites or traumas were identified. The physiopathology of perforating granuloma annulare and the process of perforation remain unknown. Numerous therapies have been proposed with variable results.