A trichodiscoma is a rare, benign follicular hamartoma that presents as an asymptomatic 2- to 4-mm skin-colored papule on the face, scalp, or upper trunk. The exact incidence of trichodiscoma is unknown, and no sex predilection has been identified. Multiple trichodiscomas may be inherited as part of the autosomal dominant Birt-Hogg-Dubé syndrome (BHD), caused by a mutation in the FCLN gene on chromosome 17. This gene is responsible for encoding a tumor suppressor protein called folliculin.

Patients with BHD present in the third or fourth decade of life with multiple fibrofolliculomas, trichodiscomas, perifollicular fibromas (fibrous papules or angiofibromas), acrochordons, and, rarely, connective tissue nevi. These patients have an increased risk of renal cell carcinoma, pulmonary cysts, and pneumothoraces and may have increased rates of colonic polyposis and medullary carcinoma of the thyroid. It is now thought that fibrofolliculomas, perifollicular fibromas, and trichodiscomas may be different developmental stages of one tumor derived from the sebaceous mantle, called a mantleoma.

Trichodiscomas are not typically seen in the pediatric population as the majority arise within the third and fourth decades of life.