Malignant lymphoma of the small intestine in multiple family members: association with an immunologic deficiency.

Four cases of malignant lymphoma all in male members of a family are described. In three of the affected individuals the primary tumor arose in the small intestine and in the other the site of origin was the retroperitoneum. Immunologic studies were carried out on the two surviving patients and on all other living members of their families. Low levels of immunoglobulins were found in one of the affected boys. During a recurrence of the tumor, the other boy showed temporary partial impairment of cellular immunity as measured by failure to react to delayed hypersensitivity skin tests, although lymphocyte transformation studies were normal. Nine months after treatment was completed his response to skin tests was normal. No immunologic defect was detected in the studies of the non-involved family members. The histologic appearance of the tumors was similar in the tissue sections which were available for review from three of the four patients; the tumor was classified as a malignant lymphoma, diffuse, mixed cell type (lymphocytic and histiocytic).