胃原発悪性リンパ腫の肉眼形態分類と発育進展様式の関係

Macroscopic Features and Growth Pattern of Gastric Malignant Lymphoma

要旨　胃原発悪性リンパ腫(以下胃悪性リンパ腫)における肉眼形態をsubmucosal tumor-like type(以下ST type; 粘膜下層・筋層を中心とする限局膨張性増殖を想定したもの)，non-submucosal tumor-like type(以下non-ST type; 粘膜に沿ったびまん性浸潤性増殖を想定したもの)，そしてcombined type(それら両型の形態を有するもの)の3つに分類した．ST typeは，胃悪性リンパ腫の27％を占めlarge cell，immunoblastic typeと有意な関連性が認められ，reactive lymphoid cell hyperplasia(以下RLH)の合併は少ない．non-ST typeは，胃悪性リンパ腫の68％を占めdiffuse，small cleaved cell type; plasmacytomaと関連性が認められ，RLH合併頻度が高い．combined typeは5％のみであった．今回の検討から胃悪性リンパ腫の肉眼形態は組織型，増殖様式，RLH合併の有無と有意に関係していることが示唆された．

　Gastric lymphoma was macroscopically classified into 3 types; ST type (lesions mimicking metastatic carcinoma, medullary carcinoma with lymphoid stroma, localized ulcerative type cancer, or leiomyosarcoma), non-ST type (lesions mimicking RLH, linitis plastica type carcinoma, or giant rugae) and combined type (combination of ST and non-ST types). Seventy seven surgically resected specimens were analyzed for evaluating the relationship among histological type, growth pattern and coexistence of RLH. The percentage of each type was as follows: ST type: 27%, non-ST type: 68%, and combined type: 5%. Most of the ST type cases were histologically, large cell, immunoblastic type or diffuse, large cell type, and showed expansive growth pattern less frequently accompanied by RLH. On the other hand, most of the non-ST type cases were diffuse, small cleaved cell type or diffuse, large cell type, and showed infiltrative growth pattern more frequently accompanied by RLH. Therefore, macroscopic type of malignant lymphoma may be related to the histological type, growth patten and coexistence of RLH; it may be useful for clinical diagnosis and treatment plan.