Japanese Clinical Guidelines 2020 for Diagnosis and Treatment of Cowden syndrome/PTEN hamartoma tumor syndrome in Children and Adults

Abstract

Cowden syndrome (CS)/PTEN hamartoma tumor syndrome (PHTS) is an autosomal-dominantly inherited rare condition caused by germline pathogenic variants of the PTEN gene. It is associated with multiple hamartomatous lesions in various organs and tissues, including the gastrointestinal tract, skin, mucous membranes, breast, thyroid, endometrium, and brain. Macrocephaly or multiple characteristic mucocutaneous lesions commonly develop by twenties. This syndrome is occasionally diagnosed in childhood by multiple gastrointestinal lesions, autism spectrum disorders, and intellectual disability. CS/PHTS may be identified by multigene panel testing in patients with cancer. Appropriate surveillance is required because patients may develop malignant tumors such as the breast cancer, thyroid cancer, endometrial cancer, colorectal cancer, and renal cancer. The present clinical guidelines explain the principles in the diagnosis and management of CS/PHTS, together with four clinical questions and corresponding recommendations. The guidelines have been designed to promote seamless implementation of accurate diagnosis and appropriate management of pediatric, adolescent and adult patients with the disease.