Sebaceous adenoma
benign sebaceoma (older term — now considered distinct)
Sebaceous adenoma is a benign neoplasm of mature sebaceous glands, distinct from the much commoner sebaceous hyperplasia. It presents as a single (or several) yellow-orange to pink, often umbilicated papule, 2–10 mm, typically on the face, scalp or trunk of an adult. The clinical importance lies almost entirely in its association with Muir-Torre syndrome (a Lynch-spectrum disorder): any sebaceous adenoma — particularly if multiple, on the trunk, in patients < 60, or with a relevant family history — should prompt mismatch-repair immunohistochemistry on the lesion and consideration of germline MLH1 / MSH2 / MSH6 / PMS2 testing.
Clinical features
- Single (or several) firm yellow-orange to pink papule, 2–10 mm, often with central umbilication.
- Distribution — face, scalp; trunk and limb lesions are particularly suspicious for Muir-Torre.
- Median age 60+; women slightly over-represented.
- Slow growth over months; may ulcerate or be mistaken for BCC.
Histology and immunophenotype
- Well-circumscribed dermal lobules of sebocytes with a peripheral rim of basaloid germinative cells.
- ≥ 50% mature sebocytes is the conventional threshold separating sebaceous adenoma from sebaceoma (intermediate) and from sebaceous carcinoma (atypia, infiltrative growth, mitoses).
- EMA, adipophilin and androgen-receptor immunohistochemistry confirm sebocytic differentiation.
- Mismatch-repair IHC (MLH1, MSH2, MSH6, PMS2) is performed on every sebaceous neoplasm in many UK pathology services as part of Muir-Torre screening.
Muir-Torre / Lynch screening
- Muir-Torre syndrome = at least one sebaceous neoplasm (adenoma / sebaceoma / sebaceous carcinoma / cystic sebaceous tumour) plus at least one visceral Lynch-spectrum malignancy (colorectal, endometrial, urothelial, small-bowel, ovarian).
- Lynch syndrome is caused by germline mutations in MLH1, MSH2, MSH6, PMS2 or EPCAM.
- Practical pathway:
- MMR-IHC on the sebaceous lesion — loss of any MMR protein flags Lynch.
- Microsatellite-instability testing if IHC equivocal.
- Refer to clinical genetics for germline testing and Lynch surveillance protocols.
- Particular care in patients with multiple sebaceous lesions, lesions on the trunk, age < 60, or a relevant personal / family cancer history.
Management
- Complete surgical excision with histology — diagnostic and definitive.
- Reassurance after excision for solitary lesions with normal MMR-IHC.
- Confirmed MMR loss — refer to clinical genetics for Lynch evaluation; in the meantime initiate Lynch-style surveillance (colonoscopy from age 25–30, gynae and urology surveillance per local protocol).
- Patient counselling — sun protection, regular skin surveillance, low threshold for biopsy of new lesions.
References
- John AM, Schwartz RA. Muir-Torre syndrome (MTS): an update and approach to diagnosis and management. Br J Dermatol; 2016.
- Singh RS, Grayson W et al. Sebaceous neoplasms — a clinicopathologic study. J Cutan Pathol; 2008.
- NICE NG151. Colorectal cancer. London: NICE; 2020 (last updated 15 December 2021; reviewed 29 April 2026). See Lynch-syndrome prevention and surveillance recommendations.
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