直腸原発悪性リンパ腫の1例

Primary Malignant Lymphoma of the Rectum, Report of a Case

要旨　患者は66歳の男性で下痢，裏急後重を主訴に来院した．便潜血は強陽性で直腸指診では肛門輪より4cmの部位を下端とする全周性の比較的軟らかい腫瘤を触知した．注腸造影所見では直腸に長径約10cmの全周性で凹凸不整の結節状の病変を認めた．特に特徴的なのは，縦軸方向への拡がりに比して，狭窄は著明でなく伸展性が保たれていることである．内視鏡所見では大小不同の結節が集簇しており，全体に黄白色調であるが，発赤や暗青色の部分が混在していた．生検では悪性リンパ腫などの非上皮性腫瘍が示唆された．術前の検索により直腸原発悪性リンパ腫と診断し，直腸切断術を行い治癒切除しえた1例を経験したので報告した．

　A 66 year-old man came to our hospital complaining of diarrhea and tenesmus, which had lasted for two months. Occult blood test of feces was positive and a rectal mass was detected by digital examination. The mass occupied the entire circle of the rectum and extended 4 to 15 cm from the anal verge. The mass was soft and there was no stricture of the rectum. The surface was uneven, but there was no ulceration. The tumor margin was clear but not elevated. Findings by a barium enema were consistent with those of digital examination. Endoscopically, the mass consisted of numerous nodules of various size. Most nodules were yellowish-white, but some showed redness or dark-blue tone. Histologic examination of the biopsy specimen was not conclusive, but suggested malignant lymphoma. Systemic involvement by the malignant lymphoma was excluded after examination of peripheral blood and bone marrow aspirate. The mass was removed totally by an abdomino-perineal operation. The size of the mass was 11.0 × 10.5 cm and staging was P₀ H₀ n₁ (+) s₂ (stage Ⅲ). The patient is now receiving VEPA treatment.

　Primary malignant lymphoma of the rectum is rare and only 39 cases have been reported in Japanese medical literature. We emphasize here that preoperative diagnosis of primary malignant lymphoma of the rectum can be made from its characteristic properties detected by digital examination, barium enema and endoscopic examination, together with histologic examination of the biopsy specimen.