PTEN hamartoma tumor syndrome (PHTS) is a term defining a group of clinically heterogeneous disorders united by a germline PTEN mutation and the involvement of derivatives of all 3 germ cell layers, manifesting with hamartomas, overgrowth and neoplasia. Currently, subsets carrying clinical diagnoses of Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, Proteus and Proteus-like syndromes and SOLAMEN syndrome (see these terms) belong to PHTS.