Thymoma-associated chronic diarrhea: A case of autoimmune enteropathy

Thymomas are tumors arising from thymic epithelial cells that are frequently associated with autoimmune conditions. One such disorder, autoimmune enteropathy, is an uncommon autoimmune process found in patients with thymoma that is characterized by chronic diarrhea (>6 weeks duration), malabsorption, and characteristic small intestinal histopathology. The presence of anti-enterocyte or anti-goblet cell antibodies supports the diagnosis of autoimmune. As this is a relatively uncommon disorder, treatment options have not been well studied. We report the case of a 35-year-old Caucasian male with recurrent thymoma that subsequently developed autoimmune enteropathy as confirmed by symptoms, biopsy and serologies. Prednisone and octreotide, which have previously been shown to treat recurrent thymoma, were used to successfully treat his autoimmune enteropathy and recurrent thymoma, leading to resolution of diarrhea, subsequent weight gain, and radiographic confirmation of regression of metastatic thymoma. Autoimmune enteropathy should be considered in the differential diagnosis of patients with thymoma presenting with intractable diarrhea and weight loss. The use of prednisone and octreotide may be helpful in treating both conditions.