Abstract

Brooke-Spiegler syndrome is an autosomal dominant disease characterized by a germline mutation in the cylindromatosis gene, CYLD, and the development of several adnexal neoplasms, including spiradenomas, cylindromas, and trichoepitheliomas. Here we present the case of an adnexal collision tumor in a patient with this condition. A 57-year-old Hispanic male presented with a long-term history of an asymptomatic, well-circumscribed, smooth, red nodule on the left helical crus. In the preceding year, the patient had several excisions of the scalp and face demonstrating isolated trichoepitheliomas and cylindromas. The presenting lesion was excised and submitted for histopathologic review. Cribriform nodules of basaloid cells with follicular differentiation were observed in a concentric fibroblast-rich stroma. Papillary mesenchymal bodies were also present. Separately, basaloid islands with ductal differentiation were identified within an eosinophilic stroma. These islands were surrounded by an eosinophilic basement membrane and arranged in a jigsaw puzzle configuration. While these two neoplastic proliferations were in close proximity, they were distinctly separate, and the diagnosis of a trichoepithelioma and cylindroma collision tumor was made. The spiradenomas, cylindromas, and trichoepitheliomas of Brooke-Spiegler syndrome typically present as distinct entities. While uncommon, any combination of these adnexal neoplasms may be identified together as a collision tumor, with spiradenoma and cylindroma collision tumors most frequently reported. Providers should be aware that these collision tumors suggest the diagnosis of Brooke-Spiegler syndrome.