Cowden's syndrome is a harmatomatous polyposis syndrome with characteristic mucocutaneous lesions and among the spectra of clinical disorders that has been attributed to germline mutations in the PTEN gene. Although Cowden's syndrome has rarely been reported, immunologic studies have revealed that patients with this syndrome have humoral and/or cellular immune abnormalities. We recently identified a 21-year-old woman with Cowden's syndrome who was diagnosed with candida esophagitis without a history of diabetes, carcinoma, or steroid therapy. We report the immunologic status of this patient and the relationship with candida esophagitis on the basis of a literature review.