An Unusual Presentation of Cronkhite-Canada Syndrome With Hypothyroidism.

Background: Cronkhite-Canada syndrome (CCS) is a rare, nonhereditary gastrointestinal polyposis characterized by diffuse polyps, hyperpigmentation, onychodystrophy, and alopecia. Hypothyroidism has been infrequently reported in association with CCS. Case Presentation: A Caucasian male in his late 70s presented with dysgeusia, asthenia, and significant weight loss, initially diagnosed with Crohn's disease. Physical examination showed onychodystrophy, hyperpigmentation, and leg edema. Laboratory tests revealed severe hypothyroidism, hypoalbuminemia, and elevated serum IgG-4 levels. Upper and lower endoscopies showed diffuse gastric and colonic polyposis with chronic inflammation, eosinophilic infiltration, and hyperplastic changes. Diagnosis of CCS was confirmed. Treatment included corticosteroids and thyroid hormone replacement. Conclusion: This case highlights CCS diagnostic challenges, particularly when misdiagnosed as inflammatory bowel disease. The coexistence of hypothyroidism and elevated serum IgG-4 levels suggests a possible autoimmune component. Early recognition of this rare syndrome is essential for appropriate management.