Hyperplastic Polyps and Juvenile Polyposis: A Diagnostic Pitfall

Abstract

Purpose: Juvenile polyposis is an uncommon condition of multiple hamartomatus polyps primarily in the colon, that usually presents at an early age. We report a case of juvenile polyposis, predominantly involving the stomach and duodenum, and presenting later in life. A 64-yearold man with diabetes, hypertension, and CAD who presented with chest pain. Examination revealed anemia and occult blood in stool. Both upper and lower GI endoscopy were performed revealing extensive gastric and duodenal polyposis, and multiple variable-sized polyps scattered throughout the colon. Initially, the resected polyps appeared as hyperplastic on pathologic examination, yet given the extensive involvement, multiple biopsies were re-examined and the diagnosis of juvenile polyposis was made. Juvenile polyps are hamartomatous polyps found primarily in infants and children, and in association with juvenile polyposis as in juvenile polyposis syndrome (JP) or Cowden syndrome (CS). Although solitary juvenile polyps are benign lesions, in JP patients, these polyps also carry risk of malignant change. Germline mutations in MADH4 and BMPR1A predispose to JP, and both genes are involved in TGF-β superfamily signaling pathways. In CS, juvenile polyps are a less consistent feature, and such patients are at risk for breast and thyroid cancers. Despite different underlying genetic mechanisms, these and other syndromes share the same phenotypic feature of juvenile polyps. Pathologically this type of polyps can be confused with hyperplastic polyps unless multiple biopsies are reviewed. This case is unique as the polyposis presented at such a late age, and while the initial pathologic examination indicated hyperplastic polyps, the extent and subsequent re-biopsy confirmed the juvenile polyposis. We report a case of juvenile polyposis in an adult patient. Our case demonstrates the importance of vigilance in the setting of extensive polyposis and to question benign pathologic examination of resected polyps since, in contrast to hyperplastic polyps, juvenile polyposis carries some risk of malignant change, and dictates implementation of appropriate genetic testing and surveillance.Figure