An unusual presentation of cutaneous sarcoidosis induced by Koebner's phenomenon.

Abstract

We report an unusual case of cutaneous sarcoidosis presenting as papulonodular lesions strictly localized to the nasal bridge and medial canthus-corresponding to areas of pressure from eyeglass frames. This rare distribution suggests the involvement of Koebner's phenomenon, a form of reactive isomorphism rarely reported in sarcoidosis. The cutaneous lesions, present for four years, led to dermatological evaluation and subsequent histopathological confirmation of sarcoidosis. Biological and radiological investigations further revealed pulmonary involvement, establishing the diagnosis of systemic sarcoidosis. The patient was treated with hydroxychloroquine and intra-lesional corticosteroids, showing marked improvement after three months and no recurrence at six months. This case underscores the importance of recognizing atypical presentations of cutaneous sarcoidosis, which may serve as an early clinical gateway to the diagnosis of systemic disease.