AbstractA case of a 55-year-old woman with malabsorption and high serum IgA level is described. On peroral jejunal biopsy the diagnosis of adult celiac disease was considered. Malabsorption temporarily improved on a gluten free diet. The serum IgA level however remained high. post-mortem examination revealed an intestinal reticulum sarcoma. The importance of serum IgA levels in Malabsorption is discussed.