Definitions

nevoid

Nevoid basal cell carcinoma syndrome

The Nevoid Basal Cell Carcinoma Syndrome (NBCCS) (also known as Basal Cell Nevus Syndrome, Multiple Basal Cell Carcinoma Syndrome, Gorlin syndrome, or Gorlin-Goltz syndrome) is an inherited group of multiple defects involving the skin, nervous system, eyes, endocrine system, and bones.

First described in 1960, NBCCS is an autosomal dominant condition that can cause unusual facial appearances and a predisposition for basal cell carcinoma, a malignant type of skin cancer. The prevalence is reported to be 1 case per 56,000-164,000 population. Recent work in molecular genetics has shown NBCCS to be caused by mutations in the PTCH (Patched) gene found on chromosome arm 9q. If a child inherits the defective gene from either parent, he or she will have the disorder.

Incidence

About 750,000 new cases of sporadic basal cell carcinoma (BCC) occur each year in the United States. Ultraviolet (UV) radiation from the sun is the main trigger of these cancers, and people with fair skin are especially at risk. Most sporadic BCC arise in small numbers on sun-exposed skin of people over age 50, although younger people may also be affected. By comparison, NBCCS has an incidence of 1 in 50,000 to 150,000 with higher incidence in Australia. One aspect of NBCCS is that basal cell carcinomas will occur on non-sun-exposed areas of the body, such as the palms and soles of the feet. These lesions may develop at the base of palmer and plantar pits. One of the prime features of NBCCS is development of multiple BCC at an early age, often in the teen years. Each person who has this syndrome is affected to a different degree, some having many more manifestations characteristic of it than others.

Components

Some or all of the following may be seen in someone with Gorlin Syndrome:

  1. Multiple basal cell carcinomas of the skin
  2. Odontogenic keratocyst: Seen in 75% of patients and is the most common finding. There are usually multiple lesions found in the mandible. They occur at a young age (19 yrs average).
  3. Rib and vertebrae anomalies
  4. Intracranial calcification
  5. Skeletal abnormalities: bifid ribs, kyphoscoliosis, calcification of falx cerebri (diagnosed with AP radiograph)
  6. Distinct facies: frontal and temporopariental bossing, hypertelorism, and mandibular prognathism

Diagnostic criteria

Diagnosis of NBCCS is made by having 2 major criteria or 1 major and 2 minor criteria.

The major criteria consist of the following:

  1. more than 2 BCCs or 1 BCC in a person younger than 20 years;
  2. odontogenic keratocysts of the jaw
  3. 3 or more palmar or plantar pits
  4. calcification of the falx cerebri
  5. bifid, fused, or splayed ribs
  6. first-degree relative with NBCCS.

The minor criteria include the following:

  1. macrocephaly.
  2. congenital malformations, such as cleft lip or palate, frontal bossing, or hypertelorism.
  3. other skeletal abnormalities, such as Sprengel deformity, pectus deformity, or syndactyly.
  4. radiologic abnormalities, such as bridging of the sella turcica, vertebral anomalies, modeling defects or flame-shaped lucencies of hands and feet.
  5. ovarian fibroma or medulloblastoma.

People with NBCCS need education about the syndrome, and may need counseling and support, as coping with the multiple BCCs and multiple surgeries is often difficult. They should reduce UV light exposure, to minimize the risk of BCC. They should also be advised that receiving Radiation therapy for their skin cancers may be contraindicated. They should look for symptoms referable to other potentially involved systems: the CNS, the genitourinary system, the cardiovascular system, and dentition.

Genetic counseling is advised for prospective parents, since one parent with NBCCS causes a 50% chance that their child will also be affected.

Treatment

Treatment is usually supportive. - Enucleation of the odontogenic cysts can help but new lesions, infections and jaw deformity are usually a result. - The severity of the basal cell carcinoma determines the prognosis for most patients. Some can be aggressive and cause death. - Genetic counseling

References

External links

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