Plasmablastic lymphoma(PBL) is a rare aggressive B-cell lymphoproliferative disorder,which has been characterized by the World Health Organization as a new entity.Although PBL is most commonly seen in the oral cavity of human immunodeficiency virus(HIV)-positive patients,it can also be seen in extraoral sites in immunocompromised patients who are HIV-negative.Here we present a rare case of PBL of the small intestine in a 55-year-old HIV-negative male.Histopathological examination of the excisional lesion showed a large cell lymphoma with plasmacytic differentiation diffusely infiltrating the small intestine and involving the surrounding organs.The neoplastic cells were diffusely positive for CD79a,CD138 and CD10 and partly positive for CD38 and epithelial membrane antigen.Approximately 80% of the tumor cells were positive for Ki-67.A monoclonal rearrangement of the kappa light chain gene was demonstrated.The patient died approximately 1.5 mo after diagnosis in spite of receiving two courses of the CHOP chemotherapy regimen.In a review of the literature,this is the first case report of PBL with initial presentation in the small intestine without HIV and Epstein-Barr virus infection,and a history of hepatitis B virus infection and radiotherapy probably led to the iatrogenic immunocompromised state. Plasmablastic lymphoma(PBL) is a rare aggressive B-cell lymphoproliferative disorder, which has been characterized by the World Health Organization as a new entity.Although PBL is most commonly seen in the oral cavity of human immunodeficiency virus (HIV)-positive patients, It can also be seen in extraoral sites in immunocompromised patients who are are HIV-negative.Here we present a rare case of PBL of the small intestine in a 55-year-old HIV-negative male.Histopathological examination of the excisional experience: Cell lymphoma with plasmacytic differentiation diffusely infiltrating the small intestine and involving the surrounding organs.The neoplastic cells were diffusely positive for CD79a,CD138 and CD10 and partly positive for CD38 and epithelial membrane antigen.Approximately 80% of the tumor cells were positive for Ki- 67.A. power of the rearrangement of the kappa light chain gene was demonstrated. Urses of the CHOP chemotherapy regimen.In a review of the literature,this is the first case report of PBL with initial presentation in the small intestine without HIV and Epstein-Barr virus infection, and a history of hepatitis B virus infection and radiotherapy possibly led To the iatrogenic immunocompromised state.