Nevoid Basal Cell Carcinoma Syndrome

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Nevoid Basal Cell Carcinoma Syndrome

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Nevoid Basal Cell Carcinoma Syndrome

Overview

Nevoid Basal Cell Carcinoma Syndrome

This section has been reviewed and approved by the Cancer.Net Editorial Board, 3/09

Overview

What is Nevoid Basal Cell Carcinoma Syndrome?

Nevoid basal cell carcinoma syndrome (NBCCS) is also known as Gorlin syndrome. NBCCS is a hereditary condition characterized by multiple basal cell skin cancers. Other common findings include jaw cysts, pits on the palms of the hands or soles of the feet, calcium deposits in soft tissues, and skeletal (bone) changes. The appearance of a person with NBCCS may include a larger head size, a prominent forehead, broad bridge of the nose, wide spaced eyes, skin cysts, and small skin bumps called milia. The jaw cysts and basal cell skin cancers usually develop in the first ten years of a person’s life, but may not appear until teenage years or early adulthood. Children with NBCCS may have the appearance features described above, including pits on their hands and feet. There is a small (5%) chance for children with NBCCS to develop a type of brain cancer called medulloblastoma.

Multiple basal cell skin cancers and jaw cysts are the most common features of NBCCS and are present in about 90% of people who have the condition. There are several other features that have been associated with NBCCS. The number of features present and the severity of symptoms can vary among people with NBCCS, even within the same family. Black people with NBCCS may have jaw cysts as their primary feature of the disease and may develop far fewer sun-related basal cell skin cancers than people with NBCCS of other races.

What causes NBCCS?

NBCCS is a genetic condition. This means that the cancer risk and other features of NBCCS can be passed from generation to generation in a family. The major gene associated with NBCCS is called PTCH. A mutation (alteration) in the PTCH gene gives a person an increased risk of basal cell skin cancer and other symptoms of NBCCS. Research is ongoing to learn more about NBCCS and to identify other genes involved.

The number of basal cell skin cancers that a person with NBCCS develops is increased by sun exposure and also by radiation therapy (for instance, a possible treatment for medulloblastoma). Some individuals have literally thousands of basal cell cancers in areas of skin that are exposed to the sun.

How is NBCCS inherited?

Normally, every cell has two copies of each gene: one inherited form the mother and one inherited from the father. NBCCS follows an autosomal dominant inheritance pattern, in which a mutation happens in only one copy of the gene. This means that a parent with a gene mutation may pass along a copy of their normal gene or a copy of the gene with the mutation. Therefore, a child who has a parent with a mutation has a 50% chance of inheriting that mutation. A brother, sister, or parent of a person who has a mutation also has up to a 50% chance of having the same mutation. It is also possible that the NBCCS in an individual was caused not by an inherited mutation, but rather by a spontaneous gene mutation (see below).

How common is NBCCS?

It is estimated that about one in 40,000 people has NBCCS. As many as 30% of people with NBCCS do not have any family history of the condition. They have a de novo (new) mutation in the PTCH gene.

How is NBCCS diagnosed?

NBCCS is diagnosed when a person has at least two major features of NBCCS and one of the minor features, or one major feature and at least 3 minor features.

Major Features

Multiple basal cell skin cancers
Increased calcium deposits in the head (seen on an x-ray)
Jaw cyst(s)
Two or more pits on the palms of the hands or soles of the feet
A parent, sibling, or child with NBCCS

Minor Features

Medulloblastoma in childhood
Increased head size
Cleft lip or palate
Abnormal shape of the ribs or spinal bones
Extra fingers or toes
Eye problems
Fibromas (benign fibrous tumors) of the ovaries or heart
Abdominal cysts

If a person has a family history of NBCCS, they are suspected of also having NBCCS if they have jaw cysts, multiple basal cell skin cancers, pits on the palms or soles of the feet, or calcium deposits in the head. Genetic testing for mutations in the PTCH gene is available for people suspected to have NBCCS. A mutation in the PTCH gene is found in up to 85% of families diagnosed with NBCCS.

What are the estimated cancer risks associated with NBCCS?

People with NBCCS have a 90% risk to develop multiple basal cell skin cancers. About 5% of children with NBCCS will have medulloblastoma.

What are the screening options for NBCCS?

Current suggested screening for people who are known or suspected to have NBCCS includes:

Neurologic evaluation every six months from birth to age 3, then every year to age 7 to look for signs of medulloblastoma
Measurement of head size regularly throughout childhood
Yearly dental x-rays, beginning at age 8 to look for jaw cysts
At least yearly skin exams to watch for basal cell skin cancer. The frequency of exams will vary by how many basal cell cancers or other skin problems a person has. Early treatment of small basal cell skin cancer reduces the amount of surgery and scarring. Regular exams should begin by the teenage years.

Due to the high risk for multiple skin cancers, people with NBCCS should avoid sun exposure and protect their skin when outside.

Screening recommendations may change over time as new technologies are developed and more is learned about NBCCS. It is important to talk to your doctor about appropriate screening tests. In general, if there is a good screening option other than tests that use ionizing radiation, that screening option should be used to avoid skin damage in people with NBCCS.

Learn more about what to expect when having common tests, procedures, and scans.

Find out more about common terms used during a diagnosis of cancer.

Questions to ask the doctor

If you are concerned about your risk of skin cancer, talk to your doctor. Consider asking the following questions of your doctor: