十二指腸球部に発生した4cm大のBrunner腺過形成の1例

Giant Brunner's Gland Hyperplasia in the Duodenal Bulb, Report of a Case

要旨　患者は55歳，女性．心窩部痛を主訴に当センター外来を受診，上部消化管内視鏡検査で十二指腸球部に巨大な隆起性病変を認めたため入院となった．上部消化管造影検査にて十二指腸球部にほぼ内腔全体を占める大きさ約4cmの亜有茎性の粘膜下腫瘍様の隆起性病変を認めた．腹部CT検査では，病変は動脈相，平衡相ともに肝臓と同程度の造影効果をもつ辺縁平滑な類円形の腫瘤として描出された．超音波内視鏡検査を施行したところ，病変は第2～3層に主座をもつやや高エコーの充実性腫瘤であり，内部に囊胞性変化をうかがわせる低エコースポットを認めた．以上の画像所見から十二指腸球部に発生した巨大な粘膜下腫瘍と診断し，心窩部痛の症状を有していたため腹腔鏡補助下の十二指腸切開腫瘤核出術を施行した．病理組織学的にはBrunner腺が粘膜下層を主体に増殖していたが，明らかな異型を認めずBrunner腺過形成と最終診断した．Brunner腺過形成は十二指腸粘膜下腫瘍の鑑別診断の1つとして重要であり，その画像所見を中心に報告した．

　A 55-year-old woman visited our center complaining of epigastralgia. Upper gastrointestinal endoscopic examination showed a large protruded lesion in the duodenal-bulb, and she was admitted to our hospital. Upper gastrointestinal x-ray examination revealed a submucosal tumor-like semipedunculated polyp, 4 cm in size, occupying the duodenal bulb. On abdominal computed tomography, the lesion was shown as a smoothedged semi-round mass, which was enhanced with the same degree as that of the liver. Endoscopic ultrasonography revealed a diffuse isoechoic mass with an anechoic spot indicating a cystic change, located in the deeper part of the mucosal layer nearest to the submucosal layer. On the basis of these findings, the lesion was strongly suspected to be a Brunner's gland hyperplasia or adenoma in the duodenal bulb, and laparoscopic tumor enucleation was performed. Histopathologically, Brunner's gland without atypia had proliferated mainly in the submucosal layer, and it was finally diagnosed as Brunner's gland hyperplasia. Since Brunner's gland hyperplasia is important as one of the differential diagnoses of submucosal tumors of the duodenum, we report this case, focusing on the image findings.