胃原発性早期リンパ肉腫（B細胞由来）の1例

Early Lymphosarcoma (B cell origin) of Gastric Origin

　近年，胃原発の悪性リンパ腫の報告は数多くみられるようになった．しかし，1965年，市川，佐野¹⁾により提起された早期胃癌の定義に準拠した，いわゆる早期の胃悪性リンパ腫の報告はまだ少ない．

　一方，リンパ球表面マーカーの知見が増えるにつれて，全身性の悪性リンパ腫および白血病の分類も再検討されており，組織学的分類に加えて免疫学的な知見を加味した分類がなされるようになってきている^2)～7)．

　54-year-old male patient was examined under mass examination. The study of the stomach revealed flecks within the faint shadows extending over a wide area from the angle to the antrum indicating the existence of multiple ulcers and erosions within the area.

　Endoscopy also disclosed small irregular-shaped multiple ulcers and erosions on the same site as visualized by X-ray The mucosa around the ulcers was faded or reddened, and had a tendency to bleed easily. The margin of this depressed lesion was not well demarcated and could not be traced exactly. This lesion was fairly glossy and the wall was very flexible.

　The biopsy and cytology examinations revealed findings suggestive of malignant lymphoma.

　In the resected specimen, multiple ulcers and erosions were noticed in the same area as had been expected preoperatively. The depressed lesion was faded and fairly glossy. It was diagnosed as a superficial type of malignant lymphoma according to the Sano's classification²⁸⁾.

　The histological examination disclosed that tumor cells, which have the characteristics of immature lymphocytes, grew in a nodular formation chiefly in the mucosa with involvement of the submucosa. Regional lymph nodes were free from malignancy. This may be celled “early lymphosarcoma of gastric origin” if the definition of early gastric cancer can be adapted.

　From histological findings, this case was diagnosed as lymphocytic, poorly differentiated lymphosarcoma, which belongs to the nodular type according to the Rappaport classification.

　Of the thirty cases of early malignant lymphoma of gastric origin, which were reported in the literature in Japan, there were twenty-five cases of reticulum cell sarcoma, four cases of lymphosarcoma, and one case of Hodgkin's sarcoma.

　In this particular case, the study of the surface markers of lymphocytes disclosed B cell origin lymphosarcoma. The study was carried out with biopsy specimens using immunofluorescent staining with antihuman T cell and B cell serum. This is the first report on the study of the surface markers of malignant lymphoma cells of gastric origin. It can be useful for an accurate morphological diagnosis and judgement of prognosis.