Anaplastic large cell lymphoma of the stomach: A case report

A case of anaplastic large cell lymphoma (so-called Ki-1 lymphoma) of the stomach in a 67-year-old man is reported. The patient was admitted to Toyama Kyoritsu Hospital because of malignant lymphoma detecled by gastroscopical biopsy. Total gastrectomy was performed. On the imprint smear from the resected stomach and lymph node, the neoplastic tissue was characterized by large isolated cells with abundant vacuolated cytoplasm and large nuclei with irregular mitotic figures. Although most cells contained one nucleus, binucleated and multilobed/multinucleated giant cells, which resembled Reed-Sternberg cells or wreathshaped multinucleated giant cells, were also seen. Cytological findings were suggestive of anaplastic large cell lymphoma. On histological sections of the stomach, cohesive/ diffuse malignant cells proliferated in the perifollicular areas of the mucosa and portions of the submucosa with fibrosis and hypervascularization. Immunohistochemically, tumor cells were positive for Ki-1 (Ber-H 2: CD 30), DAKO-CD 3, and UCHL-1 antigens, but negative for L26 (CD 20) antigen. This case was diagnosed as having T-anaplastic large cell lymphoma. This is the eleventh case report of anaplastic large cell lymphoma of the stomach, and the diagnosis was originally suspected on the basis of imprint cytology. Cytology was useful for differential diagnosis from undifferentiated carcinoma, amelanotic melanoma and Hodgkin's disease, and immunohistochemical findings were referred to in resolving the disparate findings.