A 55-year-old Hispanic man requests removal of a growth below his lower lip that arose several months ago. The lesion was traumatized by shaving but is otherwise asymptomatic. He denied drainage when the lesion was nicked with a razor. The patient has no significant medical history and had no similar lesions elsewhere.
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Shave biopsy of the lesion reveals a verrucous trichilemmoma. Trichilemmomas present as solitary or multiple papules that are either smooth or verrucoid in appearance. The head and face are the most common sites of involvement; lesions rarely exceed 5 mm in size. Trichilemmoma was first described clinically and histologically in 1962 as a benign neoplasm with differentiation toward pilosebaceous follicular epithelium.1 Because of the histologic resemblance to verrucae, a link to human papillomavirus has been postulated.2
Trichilemmomas may be a manifestation of Cowden syndrome (also known as multiple hamartoma syndrome). The condition was first identified in a single family in 1963.3 Patients present with a variety of oral and cutaneous hamartomas and have increased risk of developing breast, thyroid, and endometrial cancers.4 The genetic basis for Cowden syndrome is a mutation in the PTEN gene, a tumor suppressor gene that regulates cell cycle, cell migration, angiogenesis, and apoptosis.5
Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, as well as an associate professor of medicine at Commonwealth Medical College and a clinical instructor of dermatology at Arcadia University and Kings College.
1. Headington JT, French AJ. Primary neoplasms of the hair follicle. Histogenesis and classification. Arch Dermatol. 1962;86(4):430-441.
2. Stierman S, Chen S, Nuovo G, Thomas J. Detection of human papillomavirus infection in trichilemmomas and verrucae using in situ hybridization. J Cutan Pathol. 2010;37(1):75-80.
3. Lloyd KM, Dennis M. Cowden’s disease: a possible new symptom complex with multiple system involvement. Ann Intern Med. 1963;58(1):136-142.
4. Eng C. Cowden syndrome. J Genet Counsel. 1997;6(2):181-192.
5. Pilarski R, Burt R, Kohlman W, Pho L, Shannon KM, Swisher E. Cowden syndrome and the PTEN hamartoma tumor syndrome: systematic review and revised diagnostic criteria. J Nat Cancer Inst. 2013;105(21):1607-1616.