Gorlin syndrome associated with small bowel carcinoma and mesenchymal proliferation of the gastrointestinal tract: case report and review of literature

Fibroepithelioma of Pinkus: Solitary tumor or sign of a complex gastrointestinal syndrome

Fibroepithelioma of Pinkus (FEP), which is considered to be an uncommon variant of basal cell carcinoma, has been described in association with other systemic diseases. However, no specific studies are currently available on this subject. The aim of our study was to evaluate the clinical and morphological characteristics of FEP and investigate whether this rare tumor is a single entity or seen in the context of a more complex syndrome. We retrospectively analyzed 49 cases of FEP diagnosed and excised in a single academic institution from 1995 to 2011. The tumors were mainly located on the trunk (77.55%), followed by the lower extremities (12.20%) and the head and neck (10.20%). In 9 of the 49 cases (18%), FEP was associated with gastrointestinal tumors. The abovementioned cases are presented in an attempt to make clinicians more aware of a possible association between FEP and gastrointestinal cancer. Although a possible underlying common genetic background between FEP and gastrointestinal tumors was not provided, our study suggests that patients with FEP should be screened for the occurrence of gastrointestinal tumors.

Gastric leiomyoma in a child with Gorlin-Goltz syndrome: First pediatric case

Gorlin-Goltz syndrome (GGS), also known as nevoid basal cell carcinoma syndrome (MIM 109 400), is a rare genetic condition with a prevalence between 1/56 000 and 1/256 000. Clinical presentation is usually characterized by multiple basal cell carcinomas, odontogenic jaw keratocysts, palmar or plantar pitting and skeletal anomalies. It is furthermore associated with the development of various tumors beside basal cell carcinoma, among which medulloblastoma is the most frequent. Increased incidence of other mesenchymal neoplasms, however, is also well known: recently the first adult case of gastric leiomyoma in GGS was reported, and the inclusion of "fibromas and leiomyomas of other organs" in the minor criteria for the diagnosis was suggested. We report the first case of a pediatric patient with GGS who also developed a gastric leiomyoma: the present case illustrates the need for this change to the diagnostic criteria to encompass the highly variable presentations and phenotype in GGS.

Gas1 is a receptor for sonic hedgehog to repel enteric axons

The myenteric plexus of the enteric nervous system controls the movement of smooth muscles in the gastrointestinal system. They extend their axons between two peripheral smooth muscle layers to form a tubular meshwork arborizing the gut wall. How a tubular axonal meshwork becomes established without invading centrally toward the gut epithelium has not been addressed. We provide evidence here that sonic hedgehog (Shh) secreted from the gut epithelium prevents central projections of enteric axons, thereby forcing their peripheral tubular distribution. Exclusion of enteric central projections by Shh requires its binding partner growth arrest specific gene 1 (Gas1) and its signaling component smoothened (Smo) in enteric neurons. Using enteric neurons differentiated from neurospheres in vitro, we show that enteric axon growth is not inhibited by Shh. Rather, when Shh is presented as a point source, enteric axons turn away from it in a Gas1-dependent manner. Of the Gαi proteins that can couple with Smo, G protein α Z (Gnaz) is found in enteric axons. Knockdown and dominant negative inhibition of Gnaz dampen the axon-repulsive response to Shh, and Gnaz mutant intestines contain centrally projected enteric axons. Together, our data uncover a previously unsuspected mechanism underlying development of centrifugal tubular organization and identify a previously unidentified effector of Shh in axon guidance.