Peutz Jeghers Syndrome (PJS) is a rare genetic disorder characterized by macular lesions on the skin and mucous membranes together with hamartomatous polyps in the gastrointestinal tract, with and increased risk of developing both gastrointestinal and non gastrointestinal neoplasms. Seventy percent of cases of SPJ manifest as an autosomal dominant inherited condition, whereas the remaining 30% are the result of spontaneous mutations. The STK11/LKB1 gene is the main cause of this disorder. The purpose of this updated review is to show the newest clinical and genetic aspects.