Most (66 to 94%) cases appear to be caused by a germline mutation of the STK11/LKB1 (serine/threonine kinase 11) tumor suppressor gene. Patients are at a significantly increased risk of gastrointestinal (GI) and non-GI cancers. GI cancers include those of the pancreas, stomach, small intestine, and colon. Non-GI cancers include those of the breast, lung, uterus, ovaries, and testes.
The skin lesions are melanotic macules of the skin and mucous membranes, especially of the perioral region, lips and gums, hands, and feet. All but the buccal lesions tend to fade by puberty. Polyps may bleed and often cause obstruction or intussusception.
Diagnosis of Peutz-Jeghers syndrome is suggested by the clinical picture. Patients with perioral or buccal pigmentation and/or ≥ 2 GI hamartomatous polyps or a family history of Peutz-Jeghers syndrome should be evaluated for this syndrome including testing for STK11 mutations (see also the American College of Gastroenterology's clinical guidelines about genetic testing and management of hereditary GI cancer syndromes).
GI cancer surveillance of Peutz-Jeghers syndrome patients includes colonoscopy, upper endoscopy, and video capsule endoscopy beginning at age 8, with the timing of subsequent surveillance determined by the findings. Surveillance for breast, ovarian, endometrial, and cervical cancer should include breast self-examination starting at age 18 and then starting at age 25 should include annual pelvic examination, pelvic or transvaginal ultrasound, Papanicolaou (Pap) test, and breast MRI and/or mammogram. In addition, surveillance for pancreatic cancer should begin at age 30 and include magnetic resonance cholangiopancreatography (MRCP) or endoscopic ultrasonography. Surveillance of the testes (for Sertoli cell tumor) by testicular examination should be done annually from birth to adolescence; ultrasonography should be done if abnormalities are palpated or if feminization occurs. Although Peutz-Jeghers syndrome patients are at increased risk of lung cancer, no specific screening is recommended but should be considered if patients are smokers (see also the American College of Gastroenterology's clinical guidelines about genetic testing and management of hereditary gastrointestinal cancer syndromes).
First-degree relatives should be evaluated for skin lesions of Peutz-Jeghers syndrome.
Colonic polyps > 1 cm typically are removed.