Cowden syndrome is a rare dominantly inherited condition with predisposition to benign hamartomatous polyposis of the intestine, as well as malignant tumors of the breast and thyroid, and possibly some other cancer types. Other features include macrocephaly and dysplastic cerebellar gangliocytomatosis with ataxia, as well as predisposition to formation of trichilemmomas of the skin (1 ). The latter are tumors of the hair root sheath.
