A 29-yr-old man was admitted to the hospital because of fever, abdominal pain, nausea, and vomiting of 2 days' duration.The abdominal pain was colicky in character; it did not radiate to the back or flanks; there were no aggravating or relieving factors. He vomited 8-10 times daily a mixture of food and bile. He had 3-4 loose stools per day which did not contain blood or mucous. There was no hematemesis, melena, or hematochezia. The fever was remittent, the highest temperature spikes rising to 103°F; there were no accompanying chills or rigors.He had been hospitalized several times in the past with similar symptoms, which invariably abated 5 days after admission. Multiple laboratory tests and biopsies had been done during these hospitalizations. He had palpably enlarged cervical lymph nodes. A cervical lymph node biopsy showed an increased number of histiocytes with strongly PAS-positive granules. He had persistent normochromic normocytic anemia; serum iron levels and total iron binding capacity were low; two bone marrow biopsies were done, one of which showed diminished iron stores; the stool was guaiac negative; there was no hematuria; the reticulocyte count, serum haptoglobin, and