Teaching Case

A 52-year-old woman presented to our Dermatology department referred from her general practitioner with four skin lesions in her face suspected of being malignant. These lesions were diagnosed as basal cell carcinomas (BCC) on histology. A rare syndrome was suspected and a radiographic work-up was made.

On physical examination four skin lesions in the head were present. These lesions were submitted to histologic characterization, which revealed BCC. In addition palmar pitting was also noticed. Some teeth were missing too.
Plain skull X-ray showed the presence of falx cerebri calcifications (Fig. 1). Brain CT confirmed the falx cerebri calcifications and also shown tentorium cerebelli calcifications (Fig. 2).

Chest X-ray revealed that 3rd and 4th ribs on the right were bifid (Fig. 3). Spine X-ray showed a marked right-sided dorsal scoliosis (Fig. 4a). Given the clinical context, a CT was performed as these aspects, although unapparent on X-ray, could be in relation with hemivertebra or vertebral synostosis. CT excluded vertebral segmentation anomalies (Fig. 4b).

Head CT showed and extensive cystic lesion in the right maxilla, in relation to odontogenic keratocyst (Fig. 5)

Gorlin-Gotz syndrome (GGS), also known as Nevoid basal cell carcinoma syndrome, is a hereditary condition characterized by a wide range of developmental abnormalities and a predisposition to neoplasms. The estimated prevalence varies from 1/57, 000 to 1/256, 000 [1]. It was first reported in 1894 [1, 2, 3] but delineated by Gorlin and Goltz in 1960, as a distinct entity consisting of ectodermal and mesodermal abnormalities [4].

GGS is caused by mutations in the PTCH1 gene and is transmitted in an autosomal dominant manner with high penetrance and variable expressivity. There is no sexual predilection. Individuals with no known affected family members may comprise up to 60% of all affected individuals [1].

Many different signs and symptoms may be associated with GGS. Main clinical manifestations include basal cell carcinomas, which may appear very early (2 years of age); odontogenic keratocysts that generally develop in the first, second and third decades; palmar and/or plantar pits, and ectopic calcifications of the falx cerebri. These manifestations are considered as the major criteria for diagnosis. The disorder is also characterized by congenital skeletal abnormalities, macrocephaly with frontal bossing, cleft lip and/or palate, and eye anomalies. Various low-frequency neoplasms, such as medulloblastomas, meningiomas, and ovarian and cardiac fibromas have been also reported [1, 5].

Evans et al. [6] first established major and minor criteria for diagnosis of this rare entity, later modified by Kimonis et al. [7] According to them diagnosis of GGS can be established when two major or one major and two minor features are present [1, 5, 8] (Fig. 6)
In our case, four major criteria (multiple BCC, palmar pits, maxillary odontogenic keratocysts [although not histologically proven] calcification of falx cerebri and tentorium and bifid ribs) were detected.

The radiologic protocol for the diagnosis of this syndrome may include panoramic radiography to detect multiple jaw cysts, skull radiography for evaluation of falx cerebri calcification, chest radiography to detect bifid, fused or splayed ribs, and computed tomography as well as magnetic resonance images to find further abnormalities [9].