Trichilemmoma

A benign skin tumor originating from the outer root sheath of a hair follicle

Trichilemmoma is a benign skin tumor that arises from the outer root sheath of a hair follicle. It is considered a type of adnexal tumor, which are tumors related to skin appendages. Trichilemmomas are often associated with Cowden syndrome, a genetic disorder that predisposes individuals to multiple noncancerous, tumor-like growths.

Presentation

Trichilemmomas typically present as small, flesh-colored or slightly pigmented papules. They are most commonly found on the face, particularly around the nose and ears. These lesions are usually asymptomatic and are often discovered incidentally during a routine skin examination.

Histopathology

Under the microscope, trichilemmomas exhibit characteristic features. They are composed of lobules of clear cells that resemble the outer root sheath of a hair follicle. The cells have a glycogen-rich cytoplasm, which gives them a clear appearance. The tumor is well-circumscribed and often shows a connection to the overlying epidermis.

Diagnosis

The diagnosis of trichilemmoma is primarily based on histological examination. A skin biopsy is performed, and the tissue is examined under a microscope to confirm the presence of the characteristic clear cells and lobular architecture.

Treatment

Trichilemmomas are benign and do not require treatment unless they are causing cosmetic concerns or discomfort. In such cases, they can be removed surgically. It is important to monitor individuals with multiple trichilemmomas for signs of Cowden syndrome, as this condition requires further medical evaluation and management.

Cowden Syndrome

Trichilemmomas are one of the hallmark features of Cowden syndrome, an autosomal dominant genetic disorder caused by mutations in the PTEN gene. Individuals with Cowden syndrome have an increased risk of developing various types of cancer, including breast cancer, thyroid cancer, and endometrial cancer.

Related pages

• Cowden syndrome
• Adnexal tumor
• PTEN gene

References

• Starink, T. M. (1985). "Trichilemmoma and Cowden's disease." Journal of the American Academy of Dermatology, 13(3), 423-431.
• Brownstein, M. H., & Shapiro, L. (1973). "Trichilemmoma: A clinicopathologic study." Cancer, 32(4), 915-921.

Gallery

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  Trichilemmoma on the skin

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  Histological image of trichilemmoma

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  Trichilemmoma

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  Trichilemmoma