RLHとして4年8か月間の経過観察中に遺伝子検索で診断しえた胃MALTリンパ腫の1例

MALT Lymphoma of the Stomach Diagnosed by Gene Detection, after Being Followed Up for Four Years and Eight Months As a Pseudolymphoma, Report of a Case

要旨　患者は66歳の女性．胃RLHとして4年8か月間経過観察中，10回目の生検で“リンパ腫も否定できず”と診断され，精査のため入院した．病変は，胃体下部大彎を中心とする広範な顆粒状変化と再発を繰り返す多発潰瘍であった．生検の生材料を用いたSouthern blot法によるIgH遺伝子再構成の検索で，JH鎖のmonoclona1な再構成バンドが確認され，リンパ腫と診断した．病理組織学的には，一部でpmに浸潤するB細胞性（IgM，κ，L26陽性）MALTリンパ腫であった．更にパラフィン切片から抽出したDNAのpolymerase chain reaction法による増幅においても，IgH遺伝子のmonoclona1ityが確認された．MALTリンパ腫を念頭に置いた対応が必要であったと考える．

　A 66-year-old woman with mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach is presented. Complaining of epigastralgia, she underwent an initial endoscopic examination in March 1987. Two ulcers were found on the greater curvature of the gastric body. Although gastric lymphoma was suspected during endoscopy, the biopsy diagnosis was reactive lymphoreticular hyperplasia (RLH). Since then, she had been suffering from recurrent ulcer in spite of taking anti-ulcer medicines. Biopsy diagnoses had been consistently RLH. After the tenth biopsy in June 1991, the report suggested possible malignancy for the first time. She was referred to us and admitted to our hospital in November 1991. Gastric x-ray films and endoscopic pictures showed prominent hardening of the curvature and extensive mucosal changes spreading over the antrum to the middle body, consisting of multiple erosions, ulcers and granules. Southern blot analysis by JH probe using biopsy specimens revealed single rearranged band. With the diagnosis of malignant lymphoma, she underwent distal gastrectomy in December 1991. Histologically, prominent reactive follicles and intense infiltration of centrocyte-like (CCL) cells were spread in the mucosa and submucosa under the granular area. CCL cells had partially invaded the proper muscle in the greater curvature. Pathological diagnosis was diffuse B-lymphoma (IgM, κ, L26+), small cell type (MALT lymphoma), pm, ly₁, v₀, n(-). B-cell monoclonality was confirmed by polymerase chain reaction using DNA extract from paraffin-embedded sections. MALT lymphoma should be taken into account when the biopsy report indicates RLH of the stomach, and a gene diagnosis should be applied.