Linear unilateral basal-cell nevus syndrome with comedones
Ming H. Jih
Dermatology Online Journal 8(2): 12

History

The patient has a 38-year history of multiple papules, comedones, and cysts, which are confined to the right side of his body. He had initially presented at the age of 18 to the Newark Beth Israel Hospital for evaluation and treatment of acne vulgaris. He has been followed at the Charles C. Harris Skin and Cancer Pavilion since 1975. There was no family history of any skin disease.

Physical Examination

Figure 1	Figure 2

Numerous, waxy, translucent papules, clusters of comedones, epidermoid cysts, and areas of atrophy were distributed over the right side of the body from the face to the dorsum of the foot. The lesions did not extend past the midline of the body. Some lesions were grouped in a linear configuration and followed the lines of Blaschko. The hair, teeth, and mucous membranes were normal. A systolic heart murmur was noted.

Laboratory Data

A complete blood count and blood chemistry profile were normal. A radiographic examination of the skull and body showed dextroscoliosis of T6. A computerized axial tomography scan of the chest and pelvis was negative. Chromosomal analyses showed no abnormalities.

Histopathology

Emanating from the epidermal surface are aggregates of basaloid cells with peripheral palisading of nuclei and individual cell necrosis. There is clefting between these basaloid aggregates and the surrounding fibromyxoid stroma.

Comment

Linear unilateral basal-cell nevus syndrome with comedones is an extremely rare disease, which is characterized by the unilateral distribution of basal-cell carcinomas, comedones, epidermoid cysts, and areas of stria-like atrophy. Histologically, the papules and comedones are both basal-cell carcinomas. This disease was first described by Carney in 1952, and it is believed to be distinct from the nevoid basal-cell carcinoma syndrome (Gorlin's syndrome). In addition to the characteristic unilateral skin findings, previously reported cases have been associated with scoliosis and atherosclerotic heart disease. Atypical palmar pits were reported in one patient with this syndrome, and a second patient had calcification of the falx cerebri. However, there were no associations with any of the other distinguishing features characteristically seen in nevoid basal-cell carcinoma syndrome, e.g., odontogenic keratocysts, frontal bossing, medulloblastomas, ovarian fibromas, or bifid ribs.

There is a lack of any familial transmission. Mutations in the patched (PTCH) gene on chromosome 9q22.3 have been associated with dominantly inherited nevoid basal-cell carcinoma syndrome. However, PTCH mutations have not been associated with the linear unilateral basal-cell nevus syndrome with comedones. A current hypothesis suggests that there is a postzygotic somatic mutation which accounts for the sporadic nature of occurrence and the unilateral distribution of skin lesions.

Treatment options are determined by the number and distribution of lesions. In cases with a few isolated lesions, surgical excision and Mohs' micrographic surgery may be attempted. However, there are usually numerous lesions and continued development of new lesions which limits surgical treatment. Alternative long-term management of both linear unilateral basal-cell nevus syndrome with comedones and nevoid basal-cell carcinoma syndrome includes topical 5-fluorouracil and imiquimod.

References

© 2002 Dermatology Online Journal