肉芽性粘膜下腫瘍を形成した潰瘍を伴ったleiomyoblastomaの1例

Gastric Leiomyoblastoma with Ulceration and Extraordinary Submucosal Granulomatous Growth, Report of a Case

　胃潰瘍の潰瘍周辺には，その修復機転の1つとして肉芽組織が発生する．今回，胃体部のleiomyoblastomaに随伴した潰瘍の肉芽組織が異常な増殖を示し，粘膜下腫瘤を形成し，潰瘍と隆起の位置関係より奇異な肉眼形態を呈したと考えられる1例について，若干の考察を加えて報告する．

　A64-year-old woman underwent gastric examination because of iron deficiency anemia. A submucosal tumor 5×4 cm in diameters was seen on the posterior wall of the body. The endoscopic finding was peculiar because a deep ulcer was seen as if the oral base of the protrusion had been scooped out. The ulcer margings and converging folds were not irregular. As biopsy was also negative for malignancy, partial gastrectomy was performed under a diagnosis of a benign tumor.

　Histologically, the submucosal protrusion was caused by proliferation of granulomatous tissue, continuous with that of the ulcer base. Extraordinary proliferation of granulomatous tissue in the process of ulcer healing must have produced such asubmucosal tumor. The granulomatous tissue was edematous and of soft consistency without any eosinophilic infiltration. Partially the muscularis propria in the region of ulcer was deeply stared by H・E. It was also displaced partly by the granulomatous tissue. Here was recognized a small leiomyoblastoma. Ulcer was considered to have originated by this tumor.

　Ulcer on the submucosal tumor often occurs on the top of the protrusion, but in this case the peculiar macroscopic finding was caused by the presence of ulcer in the beginning of the protrusion as reactive granulomatous tissue due to ulcer had formed a submucosal protrusion.

　We believe that extraordinary proliferation of granulation is related with the occurrence of ulcer in the relatively sparse submucosal tissue in the side of the greater curvature and also with the patient's constitution.