Abstract： Objective To evaluate clinicopathologic features and prognosis of primary gastric anaplastic large cell lymphomas (ALCL).Methods Clinical data and parafiin blocks of 4 patients diagnosed with primary gastric ALCL were obtained. The diagnosis of all cases was based on the criteria of WHO classification of hematolymphoid neoplasm.Furthermore,chromosomal rearrangement involving ALK gene was detected by interphase fluorescence in situ hybridization (FISH) and Epstein-Barr virus (EBV) status was determined by in situ hybridization(ISH) for EBV-encoded small RNAs (EBERs).Results The patients (3 males and 1 female) were from 27 to 87 years old, with a median age of 58.5 years. All the four cases presented with a solitary ulcerative mass in stomach. Morphologically, the normal architecture of gastric wall was effaced by the diffuse infiltration of tumor cells in which the characteristic hallmark cells were easily identified.The tumor cells of all cases showed a consistently strong expression of LCA and CD30,and CD3e was expressed in 3 of the 4 cases.Both ALK expression and ALK gene rearrangements were negative in all cases.Two cases underwent total or partial gastrectomy followed by CHOP chemotherapy. Another one patient was treated with chemotherapy and autologous stem cell transplantation. None of these 3 patients developed a relapse or progression till the last follow-up on Nov 30,2011. While the rest one patient refused to take any treatment and died 20 months after diagnosis. Conclusions Primary gastric ALCL is very rare and usually ALK negative. Its pathologic features as well as the clinical outcome are quite similar to the ALK negative ALCL from other sites, except the more frequently positive CD3e Early diagnosis and proper therapy are of great significance to the prognosis.