Nevoid Basal Cell Carcinoma Syndrome

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.

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 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

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