Cutaneous sarcoidosis: a histopathological study.

ABSTRACT

BACKGROUND: Sarcoidosis is a granulomatous disease of uncertain aetiology in which the skin is frequently involved. Naked sarcoidal granulomas are the characteristic histological feature in specific lesions of sarcoidosis. OBJECTIVE: This study aims to describe the histological findings in a population of patients with cutaneous sarcoidosis. MATERIALS AND METHODS: This study is a retrospective analysis of 31 biopsies of specific lesions of cutaneous sarcoidosis, corresponding to 30 patients. RESULTS: Typical naked granuloma was found in the majority of cases (71%). In 9 cases (29%), granulomas had a significant number of lymphocytes. Necrosis was found in two cases (6%). Periadnexal distribution (mostly perisudoral) was found in 32% of cases. Interstitial distribution of granulomas was observed in five cases (16%). Foreign material was detected in 13% of cases (without the use of polarized light microscopy). Epidermal changes were found in 55% of cases, with atrophy and parakeratosis being the most frequent alterations. CONCLUSIONS: Although typical naked sarcoid granulomas are the most common features of cutaneous sarcoidosis, the dermatopathologist must be aware of possible atypical findings, which are more common than previously expected, because of the differential diagnosis with other causes of cutaneous granulomas, namely infectious diseases.