Spectrum of Tumors With Follicular Differentiation in a Patient With the Clinical Phenotype of Multiple Familial Trichoepitheliomas: A Clinicopathological and Molecular Biological Study, Including Analysis of the CYLD and PTCH Genes

Abstract

We report a patient with multiple trichoepitheliomas whose biopsy material also demonstrated a range of other neoplasms with follicular differentiation, including small nodular trichoblastoma, small nodular basal cell carcinoma (BCC), and areas resembling infundibulocystic BCC/basaloid follicular hamartoma. These were all intimately associated with otherwise typical trichoepitheliomas that dominated the microscopic appearances. Peripheral blood and tumor tissues of the patient and his 2 daughters, who apparently had a milder phenotype, were studied for alterations in the CYLD and PTCH genes, but mutations or loss of heterozygosity was not found in either gene. The occurrence of multiple follicular neoplasms within a single lesion adds evidence that, although in most cases BCC and trichoblastoma are distinct lesions, the 2 neoplasms do encompass a morphological spectrum of follicular differentiation, which is probably more overtly expressed in syndromic patients.