“Mediterranean abdominal lymphoma,” or immunoproliferative small intestinal disease. Part I: Clinical aspects

Twenty‐five cases of “Mediterranean abdominal lymphoma,” better known as immunoproliferative small intestinal disease (IPSID), are reported from the American University of Beirut Hospital. All patients were Moslem Arabs from low socio‐economical background. The mean age was 25 years. IPSID is shown in this study to be a distinct disease entity characterized by a triad of clinical, pathological and immunoglobulin abnormalities. The clinical manifestations of the disease included chronic diarrhea, weight loss, diffuse abdominal pain, clubbing of fingers and toes and occasionally palpable peripheral lymph nodes. Radiological studies revealed a malabsorption pattern with evidence of mucosal fold thickening, segmentation and flocculation of barium. Laboratory investigations showed evidence of malabsorption, hypoalbuminemia and hypocalcemia. Two patients lacked evidence of malabsorption. Nine patients had alpha heavy chain protein in the serum. However, intestinal fluid immunoelectropheresis and immunofluorescence studies on involved intestinal mucosa were not performed and therefore, alpha heavy chain disease (αHCD) could not be excluded in the remaining 16 patients. A new staging classification is proposed, and the role of laparotomy in staging is emphasized. In five patients, mesenteric lymph nodes harboured immunoblastic sarcoma whereas the intestinal mucosa in the same patients was involved with a benign‐appearing lymphoplasmacytic cellular infiltrate without evidence of malignancy. Three patients had histologically proven lymphoma in peripheral lymph nodes and all had αHCD. Lymphomatous involvement of distant organs was not observed. One patient with αHCD was considered in the premalignant phase of IPSID. Prognosis was poor as the majority of patients succumbed within two years after diagnosis. The significance of early detection is emphasized. Cancer 40:2941‐2947, 1977.