immunoproliferative small intestine disease (IPSID), a disorder characterized by small, diffuse lesions composed of cells that have features of plasma cells, histiocytes, and atypical lymphocytes. The disease mainly affects the duodenum and proximal jejunum. Patients experience diarrhea, weight loss, abdominal pain, and clubbing of the fingers and toes. Also called alpha chain disease, Mediterranean lymphoma.
