Bone Marrow Transplantation (2000) 25, 321–326  2000 Macmillan Publishers Ltd All rights reserved 0268–3369/00 $15.00 www.nature.com/bmt Case report Typhlitis complicating autologous blood stem cell transplantation for breast cancer L Boggio 1 , R Pooley 2 , SI Roth 2 and JN Winter 1 1 Department of Medicine, Division of Hematology/Oncology and 2 Department of Pathology, The Robert H Lurie Comprehensive Cancer Center, Northwestern University Medical School, Chicago, IL, USA Summary: Three cases of typhlitis occurring during autologous blood stem cell transplantation (ABSCT) for metastatic breast cancer are described. Typhlitis is a rare compli- cation of neutropenia and has uncommonly been reported in the autologous transplant setting. Although it has been most commonly described in children with leukemia, typhlitis has increasingly been reported in adult leukemias and in association with neutropenia sec- ondary to chemotherapy for a number of solid tumors. Only five previous cases of typhlitis in the setting of ABSCT have been described. Whereas diarrhea and fever are common toxicities associated with high-dose chemotherapy, it is likely that many cases of typhlitis go unrecognized. Bone Marrow Transplantation (2000) 25, 321–326. Keywords: typhlitis; neutropenic enterocolitis; breast cancer; stem cell transplantation Typhlitis was initially described in 1970 as a life-threaten- ing condition occurring in children with leukemia. 1 This condition is characterized by a necrotizing colitis usually localized to the cecum. Although most reports involve chil- dren with leukemia or aplastic anemia, 2–7 in recent years cases involving adults with hematologic malignancies have been described. 8–13 In addition, reports of typhlitis in patients with solid tumors treated with myelosuppressive doses of chemotherapy have appeared in the literature. 14–16 To date there have been five reported cases of typhlitis occurring in patients undergoing high-dose chemotherapy with autologous blood stem cell transplant (ABSCT), three from Hadassah University Hospital 17–19 and two from the Beth Israel-Deaconess Medical Center. 20 We describe our experiences with three additional cases of typhlitis com- plicating ABSCT for metastatic breast cancer. The fre- quency of typhlitis is likely to be underestimated given that Correspondence: Dr JN Winter, Northwestern University Medical School, Division of Hematology/Oncology, 303 E Chicago Avenue, Chicago, IL 60611, USA Received 4 May 1999; accepted 23 September 1999 diarrhea and fever are common side-effects of high-dose chemotherapy. Case 1 A 33-year-old athletic white female with stage IV carci- noma of the breast was treated with three cycles of adria- mycin and cyclophosphamide (AC) chemotherapy with good response. She was randomized to receive GM-CSF (Immunex, Seattle, WA, USA) 375 g/m 2 /day after cyclo- phosphamide for mobilization of peripheral blood progeni- tor cells (PBPC). Given the marginal numbers of total CD34 + cells that were collected with two attempts at mobi- lization, a bone marrow harvest was performed to serve as a backup in the event of engraftment failure. She then received the STAMP V high-dose regimen (carboplatin, cyclophosphamide, thiotepa) with daily itraconazole and acyclovir for infection prophylaxis. After infusion of the PBPC, the patient received PIXY321 (Immunex) (a recom- binant GM-CSF/IL3 fusion protein) 375 g/m 2 twice a day. On day +2, she was noted to be neutropenic and febrile (38.3°C) with loose stools, and was placed on broad spec- trum antibiotics. On day +3, she developed abdominal pain with copious diarrhea (3 liters/day). Physical examination revealed diminished bowel sounds and a diffusely tender abdomen without rebound tenderness. A radiograph of the abdomen (Figure 1) on day +4 demonstrated a distended small bowel with a thickened wall, consistent with typhlitis. Despite aggressive supportive care, she developed func- tional gastrointestinal obstruction on day +7 requiring a nasogastric tube. Stool cultures were negative for C. diffic- ile but blood cultures grew methacillin-resistant Staphylo- coccus aureus. Due to her continued neutropenia, her back- up bone marrow harvest was infused on day +9. On day +14, a stool culture was positive for Blastocystis hominis for which amphotericin was given. Stools were also posi- tive for C. difficile toxin and metronidazole was prescribed. The patient symptomatically improved with good oral intake, only one to two loose stools per day, and no abdominal pain. She continued to be febrile (38.5°C), how- ever, with an absolute neutrophil count (ANC) of 500/l on day +19. On day +20 she defervesced, her abdominal symptoms improved, and stool and blood cultures were negative for pathogens. On day +21 she was noted to be