Trichilemmal carcinoma

Definition

Trichilemmal carcinoma is an uncommon malignant tumor of the hair follicle, and is assumed to be the malignant counterpart of the benign trichilemmoma.

Description

Trichilemmal carcinomas most often occur on part of the skin that has been often exposed to the sun, like the face. The tumors look like tan or flesh-colored spots. They can resemble warts and sometimes have a hair in them. Usually, a trichilemmal carcinoma will occur as an isolated lesion.

Trichilemmal carcinomas are thought to be the malignant form of the non-cancerous tumors called trichilemmomas, which are seen in Cowden syndrome. Cowden syndrome is an inherited disorder that predisposes individuals to breast and thyroid cancer . The disease is inherited in an autosomal dominant inheritance pattern. With autosomal dominant inheritance, men and women are equally likely to inherit the syndrome. In addition, children of individuals with the disease are at 50% risk of inheriting it. Genetic testing is available for Cowden syndrome but, due to the complexity, genetic counseling should be considered before testing. Although they are thought to be related to trichilemmomas, none of the reports of trichilemmal carcinomas have been seen in patients with Cowden syndrome.

It is important to note that trichilemmal carcinoma is not the same as "malignant proliferating trichilemmal tumor, " which is usually seem on the scalp and the back of the neck.

Demographics

Trichilemmal carcinomas are most often seen in older people. They occur with equal frequency in both males and females.

Causes and symptoms

The causes of trichilemmal carcinoma are unknown. The only recognizable symptom is the presence of an unusual, tan or flesh-colored spot on the skin.

Diagnosis

Diagnosis of a trichilemmal carcinoma is very important. Because the tumors are so rare, a physician may not immediately recognize its exact diagnosis. A dermatologist will suspect an abnormality on the skin and have it removed. It is only on the pathologic examination (when a physician examines the abnormality under a microscope) that the tumor can be correctly classified.

Treatment team

The treatment of trichilemmal carcinoma will involve a dermatologist (a physician who specializes in diseases of the skin) and a surgeon (a physician who will surgically remove the tumor).

Clinical staging, treatments, and prognosis

Once a trichilemmal carcinoma has been diagnosed, a surgeon must remove it. It is necessary that documented clear margins are obtained, indicating that the entire tumor has been removed. There is a chance that the tumor will recur (return) locally (in the same spot or near the same spot). If this occurs, the recurrent tumor needs to be surgically removed as well. It is very unlikely that a trichilemmal carcinoma will metastasize (spread to other parts of the body), and further treatment with chemotherapy is not needed.

Alternative and complementary therapies

Because trichilemmal carcinoma is easily treated with removal, there are no suggested alterative and/or complementary therapies.

Coping with cancer treatment

The surgical procedure to remove a trichilemmal carcinoma is relatively straightforward and low-risk. Most surgeries will be done on an outpatient basis, requiring no stay in the hospital. A small scar on the skin may be left after the tumor is removed.

Clinical trials

No clinical trials for trichilemmal carcinoma could be identified.

Prevention

Because the underlying cause of trichilemmal carcinoma is largely unknown, preventive strategies have not been suggested.

Resources

PERIODICALS

Headington, John T. "Tumors of the Hair Follicle". American Journal of Pathology 85 (2), 1976: 480-514.

Billingsley, Elizabeth M., Thomas A. Davidowski, and Mary E. Maloney. "Trichilemmal carcinoma." Journal of the American Academy of Dermatology 36 (1), 1997; 107-109.

OTHER

Introduction of Skin Diseases. Handbook of Dermatology and Venereology. <http://www.hkmj.org.hk/skin/skintro.htm>

Kristen Mahoney Shannon, M.S., C.G.C.

KEY TERMS

Metastasize

—Cancer spreads to remote parts of body.

Pathologic examination

—When a physician examines a small section of the tumor under a microscope.