The PTEN hamartoma tumor syndrome (PHTS) includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), PTEN-related Proteus syndrome (PS), and Proteus-like syndrome. Hamartomas are focal, benign tumor-like growths. The syndromes are rare and inherited in an autosomal dominant manner. CS is characterized by the presence of multiple hamartomas in various tissues and an increased risk for malignancies of the breast, thyroid, endometrium, kidney and colorectum. A few patients with CS may have developmental delay or autism.
The prevalence of CS is unknown but is estimated at 1/200,000. The risk of developing breast cancer is about 85%, with an average age of diagnosis between 38 and 46 years. Diagnosis of CS may be based on clinical features and family history. Identification of mutations in the PTEN or other causal genes confirms the diagnosis. Management depends on the genotype of the patient, and it differs for each syndrome.
Mutations in at least four genes, PTEN, KLLN (30% of cases), SDHB and SDHD (10% of cases), have been identified in people with Cowden syndrome or Cowden-like syndrome. About 80% of people with CS have mutations in the phosphatase and tensin homolog (PTEN) gene (10q23), that encodes a tumor suppressor dual-specifity phosphatase.
Al-Khenaizan and Mohajer (2012) described a 39-year-old Saudi man with Cowden syndrome, who suffered from multiple skin lesions on the face, hands, and feet for more than 6 years. The acral keratosis were misdiagnosed and treated by many dermatologists as viral warts. He had multiple smooth-surfaced skin colored papules on the paranasal areas. Also he had hyperkeratotic skin-colored papules on the dorsal hands and feet. Multiple skin tags were seen in the neck and groin area. He had a history of lower gastrointestinal bleeding. The patient has two sons and four daughters, one of the daughters was unable to walk, two were deaf-mute, and his 13-year-old son had multiple skin-colored small papules over the forehead and cheeks, multiple palmoplantar pits, and small white papules on the anterior surface of the upper gingiva.