Cronkhite-Canada syndrome polyps infiltrated with IgG4-positive plasma cells

Cronkhite-Canada syndrome (CCS) is a rare but serious protein-losing enteropathy, but little is known about the mechanism. Further more, misdiagnosis is common due to non-familiarity of its clinical manifestation. A 40-year-old male patient was admitted to our hospital because of diarrhea and hypogeusia associated with weight loss for 4 mo. On physical examination, skin pigmentation, dystrophic nail changes and alopecia were noted. He had no alike family history. Laboratory results revealed low levels of serum albumin (30.1 g/L, range: 35.0-55.0 g/L), serum potassium (2.61 mmol/L, range: 3.5-5.5 mmol/L) and blood glucose (2.6 mmol/L, range: 3.9-6.1 mmol/L). The erythrocyte sedimentation rate was elevated to 17 mm/h (range: 0-15 mm/h). X-ray of chest and mandible was normal. The endoscopic examination showed multiple sessile polyps in the stomach, small bowel and colorectum. Histopathologic examination of biopsies obtained from those polyps showed hyperplastic change, cystic dilatation and distortion of glands with inflammatory infiltration, eosinophilic predominance and stromal edema. Immune staining for IgG4 plasma cells was positive in polyps of stomach and colon. The patient was diagnosed of CCS and treated with steroid, he had a good response to steroid. Both histologic findings and treatment response to steroid suggested an autoimmune mechanism underling CCS.