Linear trichilemmomas on the ankle of a 28-year-old female.
Trichilemmomas are benign cutaneous proliferations derived from the outer root sheath of the hair follicle. They most often occur on the head and neck region and show a female predominance. When multiple, they are associated with Cowden syndrome (CS), a rare disorder due to an autosomal dominant germline mutation in PTEN (phosphatase and tensin homolog on chromosome 10), a tumor suppressor gene. Trichilemmomas outside of the head and neck region are rare, and as such, the association with CS is not clear. A 28-year-old healthy female with no significant family history of cancer presented to her dermatologist with multiple erythematous papules on the left anterior ankle, starting at birth. A shave biopsy confirmed the diagnosis of trichilemmoma with focal desmoplastic features (or desmoplastic trichilemmoma). A PTEN immunohistochemical study showed patchy (but not complete) loss of staining of the lesional cells. After shave removal, the trichilemmomas recurred 1-2 months later.
Department of Dermatology, Tufts Medical Center, Boston, MA, USA.
Jessica L
JL
Gonzalez
Department of Dermatology, Tufts Medical Center, Boston, MA, USA.
Natalia
N
Plotnikova
Department of Dermatopathology, Miraca Life Sciences, Newton, MA, USA.
Andrew
A
Seymour
Department of Pathology and Laboratory Medicine, Hackensack University Medical Center, Hackensack, NJ, USA.
Ciaran M
CM
Mannion
Department of Dermatopathology, Miraca Life Sciences, Newton, MA, USA.
Richard
R
Danialan
Department of Dermatology, Tufts Medical Center, Boston, MA, USA.
David
D
Rosmarin
D000328:Adult; D000842:Ankle; D005260:Female; D006201:Hair Diseases / Q000473:pathology*; D018859:Hair Follicle / Q000473:pathology*; D006222:Hamartoma / Q000235:genetics / Q000473:pathology*; D006801:Humans; D051059:PTEN Phosphohydrolase / Q000032:analysis / Q000096:biosynthesis*; D012871:Skin Diseases / Q000235:genetics / Q000473:pathology*
D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
Cowden syndrome; PTEN; desmoplastic trichilemmoma; nevus sebaceus; trichilemmoma