Basal Cell Carcinoma
Other associated benign neoplasms include gastric hamartomatous polyps,congenital pulmonary cysts, cardiac fibromas, meningiomas,[72,73] craniopharyngiomas, fetal rhabdomyomas, leiomyomas, mesenchymomas, and nasal dermoid tumors. Development of meningiomas and ependymomas occurring postradiation therapy has been documented in the general pediatric population; radiation therapy for syndrome-associated intracranial processes may be partially responsible for a subset of these benign tumors in individuals with BCNS.[78,79,80] Radiation therapy of medulloblastomas may result in many cutaneous BCCs in the radiation ports. Similarly, treatment of BCC of the skin with radiation therapy may result in induction of large numbers of additional BCCs.[60,61,76]
The diagnostic criteria for BCNS are described in Table 1 below.
Table 1. Diagnostic Criteria for Basal Cell Nevus Syndrome (BCNS)
BCC = basal cell carcinoma.
|Diagnosis of BCNS supported by the presence of two major or one major and two minor criteria:|
|1. BCC: More than two BCCs or one BCC diagnosed in persons <20 y.|
|2. Odontogenic keratocysts of the jaw (histologically proven).|
|3. Palmar or plantar pits (three or more).|
|4. Bilamellar calcification of the falx cerebri.|
|5. Bifid, fused, or markedly splayed ribs.|
|6. First-degree relative with BCNS.|
|1. Macrocephaly determined after adjustment for height.|
|2. Congenital malformations.|
|�||Cleft lip or palate.|
|3. Other skeletal abnormalities.|
|�||Marked pectus deformity.|
|�||Marked syndactyly of the digits.|
|4. Radiological abnormalities.|
|�||Bridging of the sella turcica.|
|�||Vertebral anomalies (hemivertebrae, fusion or elongation of vertebral bodies, modeling defects of the hands and feet, or flame-shaped lucencies of the hands or feet).|
|5. Ovarian fibromas.|
Of greatest concern with BCNS are associated malignant neoplasms, the most common of which is BCC. BCC in individuals with BCNS may appear during childhood as small acrochordon-like lesions, while larger lesions demonstrate more classic cutaneous features. The age at first BCC diagnosis associated with BCNS ranges from 3 to 53 years, with a mean age of 21.4 years; the vast majority of individuals are diagnosed with their first BCC before age 20 years.[66,67] Case series have suggested that up to 1 in 200 individuals with BCC demonstrate findings supportive of a diagnosis of BCNS. BCNS has rarely been reported in individuals with darker skin pigmentation; however, significantly fewer BCCs are found in individuals of African or Mediterranean ancestry.[67,82,83] Despite the rarity of BCC in this population, reported cases document full expression of the noncutaneous manifestations of BCNS. However, in individuals of African ancestry who have received radiation therapy, significant basal cell tumor burden has been reported within the radiation port distribution.[67,76] Thus, cutaneous pigmentation may protect against the mutagenic effects of UV but not ionizing radiation.