Summary:A 34-year-old woman with diffuse mediastinal B cell large cell lymphoma presented 60 days after high-dose chemotherapy and autologous stem cell transplantation, and post-transplant immunotherapy with interleukin-2, with skin necrosis in the ears and extremities. Extensive work-up revealed the presence of cryofibrinogenemia and associated thrombotic vasculopathy. The patient was successfully treated with corticosteroids and therapeutic plasma exchange. However, she had recurrence of large cell lymphoma a few weeks later and died of progressive disease. Cryfibrinogenemia and skin necrosis may have occurred secondary to the imminent relapse, or as a rare complication of high-dose chemotherapy or treatment with interleukin-2. Bone Marrow Transplantation (2000) 26, 1343-1345. Keywords: cryofibrinogenemia; lymphoma; stem cell transplantation; interleukin-2 A 34-year-old woman presented with chest pain and a mediastinal mass. An open biopsy showed diffuse B cell large cell lymphoma. The patient was treated with the CHOP regimen with an initial good response. However shortly after the last cycle, she developed fever, night sweats and recurrent chest pain. She had new axillary adenopathy, as well as re-growth of the mediastinal mass and a left lower lobe lung infiltrate. She received a partial course of mantle radiation therapy with prompt resolution of symptoms. She was then given two courses of ifosfamide and etoposide, and achieved a partial response. Peripheral blood stem cells were collected after the second course. The patient proceeded to high-dose chemotherapy with the BEAM regimen. The stem cells were incubated with interleukin-2 (IL-2) prior to infusion and the patient also day 11 (with sustained ANC Ͼ1 × 10 9 /l for 3 consecutive days) and restaging tests on day 30 showed she was in complete remission. The patient completed the first maintenance course of IL-2 that was given in reduced doses (2 × 10 6 U/m 2 daily by subcutaneous injection, 25% of planned dosing) due to fevers and pancytopenia.She presented 2 weeks later, on day 56 of the transplant, with symptoms of an upper respiratory tract infection and was given oral antibiotics. A few days later she developed fever up to 38.2°C and then rapidly progressive large purpuric/necrotic lesions on her ears, and upper and lower extremities (see Figure 1). The WBC was 3.1 × 10 9 /l, hemoglobin 11.2 g/dl, and platelets 119 × 10 9 /l. A blood smear was normal with no evidence of microangiopathy. Electrolytes, creatinine, and liver function tests were within normal limits. Her LDH was 880 U/l (normal upper limit, 618). There was no laboratory evidence for disseminated intravascular coagulation (DIC). Chest X-ray showed a questionable left lower lobe infiltrate. Blood cultures were negative; serology for acute infection with EBV, CMV, hepatitis viruses and Mycoplasma was negative. PCR for hepatitis C virus RNA was negative. Repeat assays for cryoglobulins were negative. There was a low titer (1:256) of cold agglutinins. Assays of plasma for the presence of cry...