直腸悪性リンパ腫の臨床病理学的特徴

Malignant Lymphoma of the Rectum : A Clinicopathological Analysis of 23 Patients

要旨　直腸悪性リンパ腫23例（MALTリンパ腫9例，濾胞性リンパ腫3例，マントル細胞リンパ腫1例，びまん性大細胞型B細胞リンパ腫4例，T細胞性リンパ腫6例）の臨床病理学的特徴を遡及的に解析した．肉眼型と組織型に相関がみられ，隆起型ではMALTリンパ腫，びまん型・混合型ではT細胞性リンパ腫，MLP型では濾胞性リンパ腫が高頻度にみられた．非外科的治療群（化学療法，放射線，抗菌薬，無治療 ; n＝15）と外科的切除群（n＝8）では予後に差はなかった．多変量解析の結果，組織学的低悪性度（indolentリンパ腫）がoverall survivalおよびevent-free survival（EFS）のいずれにおいても独立した予後良好因子であった．穿孔，B症状，B/T免疫表現型，臨床病期はEFSのみを規定する要因であった．

　The clinicopathological features of 23 patients with malignant lymphoma of the rectum were retrospectively analyzed. Histologically, 9 cases were classified as MALT lymphoma, 3 as follicular lymphoma, 1 as mantle cell lymphoma, 4 as diffuse large B-cell lymphoma, and 6 as T-cell lymphoma. Six of 8 cases（75％）of polypoid form on macroscopy were MALT lymphomas, while 6 of 9 cases（67％）of diffuse or mixed forms were T-cell lymphomas. In addition, 3 of 4 cases（75％）of lymphomatous polyposis type were follicular lymphomas. The overall survival（OS）and the event-free survival（EFS）did not differ between patients who were treated non-surgically（watchful waiting, antibiotics, chemotherapy or radiotherapy ; n＝15）and those treated by surgery（n＝8）. Cox multivariate analysis revealed that indolent histology（MALT lymphoma or follicular lymphoma）was an independent prognostic factor for both OS and EFS. Intestinal perforation, B symptoms, B/T phenotype and clinical stage were also independent prognostic factors for EFS, but not for OS.