Brooke-Spiegler syndrome: Multiple tumors arising from structures in the skin such as hair follicles and sweat glands characterize the syndrome. Mutations in a gene known as CYLD cause Brooke-Spiegler syndrome. These mutations are inherited in an autosomal dominant manner, meaning only one copy of the defective gene is necessary to cause the condition. However, a second non-inherited mutation is necessary for the development of the skin tumors. The skin tumors that occur in Brooke-Spiegler syndrome are usually benign but are occasionally malignant, or cancerous. Trichoepitheliomas, spiradenomas, and cylindromas are among the types of skin and skin appendage tumors that occur in people with this condition.
