自然消失した胃原発悪性リンパ腫の1例

Gastric Malignant Lymphoma with Spontaneous Regression in a Short Period, Report of a Case

要旨　患者は64歳の男性．1992年12月の胃内視鏡検査で，胃角部の後壁に辺縁が鋭利な不整形陥凹と粗大胃小区から成る軽度隆起を認め，ⅡC型早期胃癌を疑った．生検は低分化腺癌とされた．9日後の胃X線像では陥凹部がやや縮小したが，悪性サイクルに伴う変化と考えて初回検査の約1か月後に外科切除となった．全割標本の詳細な病理学的検索を行ったが腫瘍細胞はなく，Ul-ⅡSの消化性潰瘍瘢痕のみでリンパ節転移もなかった．生検標本を再検討したところLCA(＋)，L26(＋)，keratin(－)，UCHL(－)でdiffuse medium sized cell typeの悪性リンパ腫であった．早期と考える胃原発性リンパ腫が約1か月の経過中に病巣内の潰瘍化により脱落消失したものと考えた．

　A 64-year-old man visited our hospital for gastric endoscopic examination. Endoscopic examination (Dec. 7, 1992) revealed an irregular ulceration with surrounding coarse mucosa on the posterior wall of the gastric angulus (Fig.1) . X-ray examination (Dec. 16, 1992) showed an irregular shaped shallow ulceration with a faint ulcer mound on the posterior wall of the gastric angulus (Fig. 2) . The image of the tumor with an irregular ulceration seemed to have become smaller in size than the size at the initial endoscopic examination. From these roentogenographic and endoscopic features, the diagnosis of type Ⅱc early gastric cancer was made and biopsy specimens also confirmed its malignancy. Subtotal gastrectomy was performed on Jan. 6, 1993. In microscopic examination of the resected specimen, submucosal fibrosis (Ul-Ⅱs) was recognized (Fig. 3) . However there was no malignant lesion in the resected specimen and regional lymph nodes were free from invasion. So biopsy specimen were restudied. In immunohistochemical staining for Leukocyte common anigen (LCA) and L26, tumor cells uniformly reacted with LCA and L26 antibodies, giving evidence of B-cell origin. However tumor cells didn't react with keratin and UCHL. Final histological diagnosis was medium sized cell type malignant lymphoma (Fig. 4, 5) . This clinical and histological course suggested the existence of a socalled “malignant cycle” of the malignant lymphoma.