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A patient, aged 15 years, presented for a skin check. Her past medical history is significant for several basal cell carcinomas on her face. She developed the first basal cell carcinoma at age 12 years.
On exam, a benign-appearing papule near the eyelid was noted, but biopsy proved the liaison to be a basal cell carcinoma. Pits on the palms and soles were also reported.
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Gorlin basal cell nevus syndrome or nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disease in which patients are predisposed to develop multiple basal cell carcinomas (BCCs). NBCCS is due to mutations in the patched 1 (PTCH1) gene that suppress tumors on chromosome 9q.
Skin lesions range from small, pinpoint to large, nodular BCCs. Tumors on the eyelids, axillae, and neck are generally pedunculated and are often symmetric on the face.
Half of patients present with palmoplantar lesions that resemble small pits that range from pinpoint to several millimeters in size and one millimeters deep. Patients may have frontal bossing, broadened nasal root, and hypertelorism.
Other symptoms may variably express in different organ systems including skeletal malformations, eyes, soft tissue, central nervous system, and endocrine organs. A review of systems may show congenital anomalies including undescended testes; hydrocephalus, mandibular jaw; and odontogenic keratocysts, which may be multiple and may be unilateral or bilateral.
There may be defective dentition, bifid or splaying of ribs, pectus excavatum, short fourth metacarpals, scoliosis, and kyphosis. Eye lesions include strabismus, hypertelorism, dystopia canthorum, cataracts, glaucoma, and coloboma with blindness.
There may be agenesis of the corpus callosum, calcification of the falx, and medulloblastoma. Intellectual disability, however, is rare. Fibrosarcoma of the jaw, ovarian fibromas, teratomas, and cystadenomas have been reported.
Sun exposure and radiation therapy increases the risk of developing BCCs. Radiation therapy should be avoided in patients diagnosed with NBCCS.
Diagnostic workup
The following studies are indicated in patients suspected of having NBCCS:
- Skull radiograph or computed tomography (CT) scan, which can indicate a calcified falx cerebri, complete or partial bridging of the sella turcica, or a broadened nasal root
- Panoramic film can help identify odontogenic keratocysts, while magnetic resonance imaging (MRI) may help show the internal composition of the cysts
- Chest x-ray documents rib abnormalities
- Hand and foot x-rays will show flame-shaped lucencies (lytic bone lesions) in 30% of hand films and 17% of foot films
- Skin biopsy of skin growths may show features of basal cell carcinoma
Patients diagnosed with NBCCS should visit a dermatologist every two to three months, especially during adolescence. Starting at age eight years, annual panoramic radiographs of the jaw are recommended.
To exclude medulloblastoma, cranial MRIs should be performed annually until the age eight years. Periodically, echocardiography to exclude cardiac fibroma should be performed.
For infants with a family history of NBCCS, early diagnosis may be achieved via screening radiography to look for calcification of the falx, rib anomalies, or calcified ovarian fibromas.
Because of the large number of lesions, treatment of basal cell carcinomas (BCCs) in these patients may be extremely difficult. Lesions that are growing, or that become invasive, should be excised or curetted and electrodesiccated. More aggressive tumors or tumors located in delicate or high-risk areas may benefit from Mohs’ micrographic surgery.
Naveen Pattisapu, BS, is a medical student at Baylor College of Medicine
Adam Rees, MD, a graduate of the David Geffen School of Medicine at UCLA, practices dermatology in Los Angeles.
References
- Barankin, B, et al. “Nevoid basal cell carcinoma syndrome.” UpToDate. 28 May 2014. Retrieved 11/20/2014 from: http://www.uptodate.com/contents/nevoid-basal-cell-carcinoma-syndrome?source=search_result&search=nevus+gorlin&selectedTitle=1%7E142
- Stanich, PP et al. UpToDate. “PTEN hamartoma tumor syndrome, including Cowden syndrome.” 29 May 2014. Retrieved from: http://www.uptodate.com/contents/pten-hamartoma-tumor-syndrome-including-cowden-syndrome?source=machineLearning&search=cowden+syndrome&selectedTitle=1%7E65§ionRank=1&anchor=H462459902#H462459902
- Wolff K et al. Fitzpatrick’s color atlas and synopsis of clinical dermatology. 2013.