Germline mutation of the PTEN gene in a Japanese patient with Cowden's disease

Cowden's disease (CD) is an autosomal dominant disorder which confers a high susceptibility to diverse benign and malignant tumors. The PTEN (phosphatase and tensin homologue deleted in chromosome ten) gene has been identified as a tumor suppressor gene responsible for cancers of the endometrium, ovary, prostate, and glioblastomas. Recently, germline mutations of this gene were also found in patients with CD, and it is now recognized as a gene responsible for this disease. We identified a germline nonsense mutation at codon 130 in exon 5 of PTEN in a 56-year-old Japanese woman with CD. The patient had adenoid facies and mucocutaneous lesions including multiple facial papules, acral keratoses on neck and shoulders, palmoplantar keratoses, multiple oral papillomas, scrotal tongue, mucosal and cutaneous hemangiomas, and a sclerotic fibroma on the arm. She also had benign and malignant polypoid neoplasms throughout the entire digestive tract, including adenocarcinoma of the colon and submucosal lipomas of the rectum, as well as bilateral breast carcinomas, multinodular goiters, an ovarian cyst with a fibroma-like nodule, hepatic hemangiomas, and abdominal hernia. We searched CD cases with the same genotypic PTEN mutation as the present case and compared their phenotypes. Further studies will disclose a better understanding of the role of mutation in the PTEN gene in the course of tumorigenesis of both benign and malignant tumors developed in patients with CD.