悪性リンパ腫の大腸微小病変に関する内視鏡的検討

Colonoscopic Study of the Minute Metastatic Lesions of Malignant Lymphoma

要旨　悪性リンパ腫の浸潤，転移によると思われる，多発性大腸微小病変（5mm以下）の内視鏡的および生検組織学的検討を行った．大腸内視鏡的特徴は，中心陥凹を有する平滑な粘膜下腫瘍または扁平隆起が多発し，全大腸にほぼ均等に分布していた．通常の腫大したリンパ濾胞よりも平坦な形態が多く，色素撒布による注意深い観察が必要であった．病理組織学的所見の特徴はいずれもびまん性悪性リンパ腫（B細胞型）で，粘膜下層を中心に比較的境界明瞭，かつ密に浸潤・増殖していた．病巣内には胚中心を伴う濾胞構造はほとんど認められなかった．

　We reported three cases of malignant lymphomas with multiple metastatic lesions in the large intestine. All cases were comfirmed and they generally involved lymphadenopathy, and were diagnosed pathologically as non-Hodgkin's lymphoma by using biopsy specimens of the superficial lymph node.

　Colonoscopic studies were performed especially to detect minute lesions less than 5 mm in diameter in all cases. Tiny smooth submucosal tumors with characteristically central depression were detected by colonoscopy using the dye method. A few minute flat elevations accompanied with enlargement of the pit pattern were noticed by TV colonoscope after indigo carmine spray. Distribution of these lesions was equal throughout the large intestine.

　Differential diagnosis from benign lymphoid hyperplasia was described.

　In most of these menute lesions, the proliferation of atypical lymphocytes was demonstrated by pathological examination of direct-vision biopsy specimens.

　A characteristic pathological finding was the relatively well demarcated proliferation of lymphoma cells from the submucosal layer to the lamina propria. Superficial erosions of the epithelium were noticed in some biopsy specimens. No follicular structure with germinal center was recognized in the lesions of malignant lymphoma.

　It is concluded that dye endoscopy and direct-vision biopsy are very usefull for diagnosis of minute colonic lesions of malignant lymphoma.