Immunoproliferative small intestinal disease: Mediterranean lymphoma and alpha heavy chain disease.

Gastrointestinal lymphoma, uncommon in the West, is far more prevalent in developing countries where it falls into two groups: 'Western'-type lymphomas, similar to those seen in developed countries, and the so-called Mediterranean-type lymphoma. It is now accepted that Mediterranean lymphoma represents, in the majority if not in all cases, the late stage of alpha heavy chain disease (alpha-HCD). This disease is characterized by abnormal secretion of an immunoglobulin fragment; alpha-HCD and Mediterranean lymphoma constitute two ends of a spectrum of pathology now classified as immunoproliferative small intestinal disease (IPSID). IPSID is associated predominantly with poor socioeconomic conditions; patients present with progressive malabsorption in the second and third decades of life. Diagnosis is established by small bowel biopsy, with or without high serum levels of the alpha heavy chain protein. Treatment consists of an initial staging laparotomy, with debulking of lymphomatous deposits if appropriate, followed by chemotherapy or radiotherapy. Overall prognosis is poor but the recent use of doxorubicin-based chemotherapy offers some hope for the future.