PTEN and Cowden disease: The most common phenotype seen in PTEN variants is Cowden syndrome, consisting of multiple hamartomas found on skin and GI tract, vascular abnormalities, mucocutaneous features including trichilemmomas, papillomatous papules, lipomas, fibromas, and a severe risk for benign and malignant tumors of the thyroid, breast, and endometrium (Blumenthal and Dennis, 2008).