Neutropenic enterocolitis (NE) is also known as typhlitis, ileocecal syndrome, cecitis, or necrotizing enterocolitis. Despite the previous use of the term "necrotizing enterocolitis" to describe NE cases, necrotizing enterocolitis is a different inflammatory illness seen in newborns and is beyond the scope of this review. NE is a clinical entity initially described in leukemic pediatric patients. It has also been repoed in adults with hematologic malignancies such as leukemia, lymphoma, multiple myeloma, aplastic anemia, and myelodysplastic syndromes, as well as other immunosuppressive causes such as AIDS, therapy for solid tumors, and organ transplant. The true incidence of NE is unknown. One systematic review published in 2005 suggested a pooled incidence of 5.6% in hospitalized adults with hematological malignancies, chemotherapy for solid tumors, and aplastic anemia. The repoed moality also varies with rates as high as 50%. NE was repoed initially after the use of taxane drugs, but more recently an increasing number of chemotherapeutic drugs have been implicated. Other drugs linked to NE include cytosine arabinoside, gemcitabine, vincristine, doxorubicin, gemcitabine, cyclophosphamide, 5-fluorouracil, leuvocorin, and daunorubicin. Immunosuppressive therapy for organ transplant, antibiotics, and sulfasalazine for the treatment of rheumatoid ahritis have also been considered causes of NE. PATHOGENESIS The exact pathogenesis of NE is not completely understood. The main elements in disease onset appear to be intestinal mucosal injury together with neutropenia and the immunocompromised state of the afflicted patients. These initial conditions lead to intestinal edema, engorged vessels, and a disrupted mucosal surface, which becomes more vulnerable to bacterial intramural invasion. Chemotherapeutic agents can cause direct mucosal injury (mucositis) or can predispose to distension and necrosis, thereby altering intestinal motility. Cytosine arabinoside (cytarabine) is a chemotherapeutic agent used to treat leukemia and lymphoma that is paicularly associated with the development of NE. Intestinal leukemic infiltration is another potential factor in the pathogenesis of NE, which may explain the presence of acute myelogenous leukemia presenting as NE before the onset of chemotherapy regimens Ref Davidson edition23rd pg 836