RESUMO
Immunoproliferative small intestinal disease is an extranodal marginal zone B-cell lymphoma that arises from mucosa-associated lymphoid tissue and is associated with defective α heavy chain protein secretion. We present a case of an 18-year-old male patient admitted with diarrhea and weight loss who had previously received a liver transplant at the age of 19 months to treat biliary atresia. He underwent a thorough investigation and was diagnosed with immunoproliferative small intestinal disease lymphoma. The patient was switched from tacrolimus to everolimus and commenced on doxycycline treatment for 6 months and achieved long-term remission. Currently, 7 years after diagnosis, he is asymptomatic without evidence of histological relapse. This is the first case of immunoproliferative small intestinal disease described in a liver transplant recipient.