Colonic lymphoma producing alpha-chain disease protein.

Alpha-chain disease with involvement of small intestine-resulting in characteristic villus atrophy and malabsorption has not been reported in this country. We studied a 57-yr-old male who presented with a polypoid tumor of the hepatic flexure of the colon. There was no evidence of malabsorption as manifested by a normal fat balance, serum carotene, and D-xylose absorption studies and the small bowel biopsy did not show villus atrophy. The tumor in the colon was surgically removed and diagnosed as a malignant lymphoma of lymphocytic type. Tumor tissue infiltrated in the mesentery could not be excised. Alpha-chain disease protein was demonstrated in serum and urine, and also in tumor tissue by immunoperoxidase techniques. The alpha-chain disease protein was further purified and classified as subclass 1. The patient had a good clinical response to cyclophosphamide and prednisone, but still has intraabdominal lymphoma with gastric involvement, and his serum alpha-chain protein persists. This case report may represent a distinct variant of alpha-chain disease.