胃悪性リンパ腫の症例を見て―病理の立場から

Malignant Lymphoma of the Stomach: Collected eighty-seven cases

　胃悪性リンパ腫の特集号を組むにあたって多数の機関の御好意により，多くの症例を御提供いただいた．このうち，臨床資料，切除胃肉眼写真および病理組織標本がそろった例は87例であった．これら症例が複数の人々によって検討されたのを機会に，検討症例の病理形態学的所見を略述してみた．

　肉眼所見　分類と各肉眼型の出現頻度とはすでに「胃悪性リンパ腫の集計成績」で述べられている．これらを通観して，胃悪性リンパ腫の肉眼所見には以下のような特徴が挙げられる．

　Eighty-seven cases of primary malignant lymphoma of the stomach was sent to a subcomittee from many institutions for detection of their characteristics.

　Macroscopically, the malignant lymphoma is divided into mass-forming type, superficial spreading type, giant rugal type and others; each, occupies 54.0%, 20.2%, 4.4% and 21.4%. Others comprise mixed type, and small early carcinoma-like patterns; Ⅱa, Ⅱc+Ⅲ, Ⅲ+Ⅱc, Ⅲ and Ⅱa+Ⅱc.

　The macroscopic characteristics of gastric malignant lymphoma are summarized as follows: (1) there are areas with intramural tumor pattern, (2) outline of the lesion is not necessarily clear especially in the cases of superficial spreading type, (3) mass-forming type is expansive and have sharp, circular, elevated ulcer-margin, (4) the stomach is flexible and not deformed, irrespective of presence of malignant lymphoma of mass-forming type or giant rugal type, and (5) the tumor has multiple erosions and ulcers.

　Histologically, the tumors, by Rappaport classification, consist of forty-four cases of histiocytic type (51%), thirty cases of poorly differentiated lymphosarcoma (35%), eight cases of well differentiated lymphosarcoma (3%), three cases of mixed type (3%) and two cases of Hodgkin's disease (2%).

　Macroscopic differentiation of gastric malignant lymphoma from other diseases is as follows: massforming type of lymphoma v.s. expansive ulcerating carcinoma, oat-cell carcinoma, carcinod and benign ulcer, and superficial spreading type of lymphoma v.s. benign lymphoid hyperplasia, multiple ulcers, superficial spreading carcinoma, leukemic infiltration and tuberculosis, and giant rugal type of lymphoma v.s. carcinoma of linitis plastica type, benign lymphoid hyperplasia, giant rugal hypertrophy and Cronkhite-Canada syndrome.

　Microscopically, malignant lymphoma must be differentiated from benign lymphoid hyperplasia, poorly differentiated medullary adenocarcinoma, carcinoma with lymphoid stroma, oat-cell carcinoma and leukemic infiltration.