113: Nevoid Basal Cell Carcinoma Syndrome

Key Points

• Disease summary:

  • Nevoid basal cell carcinoma syndrome (NBCCS) is characterized by multiple basal cell carcinomas and odontogenic keratocysts.

  • A characteristic appearance including facial milia, frontal bossing, wide nasal bridge, coarse facial features, high-arched eyebrows and palate, mandibular prognathism, and macrocephaly may be present. Palmar and plantar pits, skeletal abnormalities of the ribs, and vertebrae and ectopic calcification of the falx cerebri are often found and useful in diagnosis.

  • Individuals are also at increased risk for developing other cysts and neoplasms including medulloblastoma and cardiac and ovarian fibromas.

• Hereditary basis:

  • NBCCS is inherited in an autosomal dominant fashion, with approximately 70% to 80% of patients receiving an affected gene from a parent and the remaining 20% to 30% representing de novo mutations. Penetrance is near complete.

• Differential diagnosis:

  • While other inherited disorders such as susceptibility to basal cell carcinoma (BCC), Bazex syndrome and Rombo syndrome should be considered in the setting of multiple BCCs, NBCCS should be highly suspected in cases of odontogenic keratocysts or early-onset medulloblastoma, see Table 113-1.

Diagnostic Criteria and Clinical Characteristics

Diagnostic Criteria for Nevoid Basal Cell Carcinoma Syndrome

Diagnosis may be made in the presence of two major and one minor criterion or one major and three minor criteria.

• Major criteria:

  • Multiple BCCs

    • Greater than five in a lifetime or one under age 30

  • Odontogenic keratocyst

  • Palmar or plantar pits

    • Two or more

  • Ectopic calcification

    • Lamellar calcification of the falx or calcification of the falx at less than 20 years

  • First-degree relative with NBCCS

• Minor criteria:

  • Congenital skeletal anomaly

  • Macrocephaly

    • Occipitofrontal head circumference greater than 97th percentile

  • Ovarian or cardiac fibromas

  • Childhood medulloblastoma

  • Lymphomesenteric or pleural cysts

  • Cleft lip or palate

  • Preaxial or postaxial polydactyly

  • Ocular anomalies

Clinical Characteristics

Appearance

Many patients have a characteristic appearance with coarse facial features, frontal bossing, high-arched eyebrows and palate, wide nasal bridge, mandibular prognathism, macrocephaly, and facial milia. Shoulders are downward sloping and some patients may be very tall.

Basal Cell Carcinomas

Early skin lesions may have the appearance of nevi. Carcinomas are ...