Brooke-Spiegler syndrome is a rare genodermatosis characterized by a triad of cutaneous adnexal tumors: cylindromas, spiradenomas, and trichoepitheliomas. This syndrome is inherited in an autosomal dominant pattern, thus affecting males and females in equal numbers, but limited evidence suggests that females may be more severely affected than their male counterparts. Tumors typically arise during late childhood or early adolescence, preferentially in the head and neck region, but new lesions may continue to develop throughout a patient's lifetime. Although most lesions are benign and require no further intervention, the location, size, and number of tumors may be disfiguring or disabling, potentially impairing vision or hearing. Rarely, these tumors may also undergo malignant transformation and may even metastasize.

This syndrome is caused by a mutation in the tumor suppressor gene CYLD, which is located on the 16q chromosome. Currently, there are 68 known mutations associated with Brooke-Spiegler syndrome.

Two similar conditions, familial cylindromatosis and multiple familial trichoepithelioma, are also caused by mutations in the CYLD gene, and given their overlapping clinical features, are considered phenotypic variants of Brooke-Spiegler syndrome. In familial cylindromatosis, affected patients develop only cylindromas, and in multiple familial trichoepithelioma, patients exclusively develop trichoepitheliomas.