before advances in the diagnosis of treatment of Peutz–Jeghers syndrome were made). Probably due to this limited evidence base, cancer risk estimates for Peutz–Jeghers syndrome vary from study to study. There is an estimated 18–21% risk of ovarian cancer, 9% risk of endometrial cancer, and 10% risk of cervical cancer, specifically adenoma malignum. Diagnosis The main criteria for clinical diagnosis are: Family history Mucocutaneous lesions causing patches of hyperpigmentation in the mouth and on the hands and feet. The oral pigmentations are the first on the body to appear, and thus play an important part in early diagnosis. Intraorally, they are most frequently seen on the gingiva, hard palate and inside of the cheek. The mucosa of the lower lip is almost invariably involved as well. Hamartomatous polyps in the gastrointestinal tract. These are benign polyps with an extraordinarily low potential for malignancy. Having 2 of the 3 listed clinical criteria indicates a positive diagnosis. The oral findings are consistent with other conditions, such as Addison's disease and McCune–Albright syndrome, and these should be included in the differential diagnosis. 90–100% of patients with a clinical diagnosis of PJS have a mutation in the STK11/LKB1 gene. Molecular genetic testing for this mutation is available clinically. Management Resection of the polyps is required only if serious bleeding or intussusception occurs. Enterotomy is performed for removing large, single nodules. Short lengths of heavily involved intestinal segments can be resected. Colonoscopy can be used to snare the polyps if they are within reach. Prognosis Most patients will develop flat, brownish spots (melanotic macules) on the skin, especially on the lips and oral mucosa, during the first year of life, and a patient's first bowel obstruction due to intussusception usually occurs between the ages of six and 18 years. The cumulative lifetime cancer risk begins to rise in middle age. Cumulative risks by age 70 for all cancers, gastrointestinal (GI) cancers, and pancreatic cancer are 85%, 57%, and 11%, respectively. A 2011 Dutch study followed 133 patients for 14 years. The cumulative risk for cancer was 40% and 76% at ages 40 and 70, respectively. 42 (32%) of the patients died during the study, of which 28 (67%) were cancer related. They died at a median age of 45. Mortality was increased compared with the general population. A family with sinonasal polyposis were followed up for 28 years. Two cases of sinonasal type adenocarcinoma developed.