腸管悪性リンパ腫の鑑別診断―病理肉眼所見から

Malignant Lymphoma of the Intestinal Tract: Macroscopic Differential Diagnosis

要旨　病理学的に確認されえた腸管原発悪性リンパ腫23例について，臨床病理学的検討を行い，それらの肉眼的特徴から以下の5群に分類した．（1）隆起型，（2a）潰瘍型（周堤を伴うもの），（2b）潰瘍型（周堤を伴わないもの），（3）びまん浸潤型，（4）その他．悪性リンパ腫の特徴として，①多発病巣が多い（52％），②腫瘍（特に粘膜下腫瘍）としての性格表現と炎症性疾患に類した形態表現の両者を合わせ示すことが多い，③非上皮性腫瘍かつfree cell（遊離細胞）としての形態表現のものがある，などが指摘しうる．これらの特徴を踏まえ，各肉眼型ごとに癌，筋肉腫，脂肪腫，潰瘍形成性炎症性疾患など類似疾患との肉眼的鑑別診断について述べた．

　Twenty-three cases of primary malignant lymphoma of the intestine were clinicopathologically reviewed in order to discover the characteristic macroscopic features for its differential diagnosis from carcinoma, nonepithelial tumors other than lymphoma, and inflammatory diseases of the intestinal tract. The lymphomatous lesions in the 23 cases were classified into four gross types according to modified classification by Watanabe.

　They were : 1) polypoid type (7 lesions), 2a) ulcerative type with marginal wall (12 lesions), 2b) ulcerative type without marginal wall (3 lesions), 3) diffusely infiltrative type (7 lesions).

　Multiple lesions were found in 12 of the 23 cases (52%, inclùding diffusely infiltrative type). In these cases, there was a tendency for multiple small polypoid lesions with erosion on the center (like verrucous lesions in the stomach) or swollen edematous mucosa to be found around the main polypoid or ulcerative lesion. There findings were similar to those found in inflammatory diseases of the intestinal tract. These findings suggest that malignant lymphoma possesses and demonstrates tumor (mass) forming neoplastic characteristics, and non-epithelial, free cell characteristics mimicking those of inflammatory diseases. On the basis of these characteristic findings of lymphoma, we described macroscopic differential diagnosis of malignant lymphoma from carcinoma, nonepithelial tumors (such as leiomyoma,―myosarcoma and lipoma), and inflammatory diseases (ulcerative colitis, tuberculosis,Crohn's disease,Behcet's disease, simple ulcer, and so on).