A rare cause of ulcerative colitis - diarrhoea and perianal bleeding due to posttransplant lymphoproliferative disorder (PTLD).

Post-transplant lymphoproliferative disorder (PTLD) is characterised by frequent extranodal manifestation, in 20 - 25 % including the gastrointestinal tract. This entity, which is more frequent after solid organ transplantation, rarely occurs after bone marrow transplantation (BMT). We report the case of a 43-year-old male presenting with a short history of rectal bleeding, diarrhoea and weight loss. He had received a bone marrow transplant two years previously for an acute lymphocytic leukaemia of B-cell origin. On sigmoidoscopy, deep ulcerations of the rectal and sigmoideal mucosa were found. Further investigations revealed a diffuse infiltration of the liver, spleen, both kidneys and lungs. Histologically, a monomorphic post-transplant lymphoproliferative disorder was diagnosed, the subtype was a high grade diffuse-large cell Non-Hodgkin's lymphoma of B-cell origin. The biopsies showed that a major proportion of cells expressed Epstein-Barr virus encoded proteins typical for latent as well as lytic EBV infection. This is a common feature of PTLD and possibly plays a critical role in its pathogenesis. The current therapeutic approach to the subtype of PTLD we saw in this patient is CHOP chemotherapy, comprising the anti-CD 20 antibody rituximab if CD 20-positivity is present. This patient had a fatal course of the disease and died a few days after the first chemotherapy cycle due to severe multiple organ failure.