直腸granular cell tumor（顆粒細胞腫）の1例

Granular Cell Tumor of the Rectum, Report of a Case

要旨　下部直腸の顆粒細胞腫（granular cell tumor）の1例を報告した．患者は43歳，男性で主訴は血便と下腹痛．X線，内視鏡検査で直腸下部後壁の粘膜下腫瘍と診断され，外科的に経肛門的局所切除が施行された．腫瘍は最大径15mmで割面は白色であった．病理組織学的にはH・E染色で胞体内に顆粒を認め，免疫組織染色でS-100蛋白陽性，desmin陰性であった．

　A case of granular cell tumor was reported. The patient was a forty-three year-old male, who complained of melena and lower abdominal pain. A small submucosal tumor of the lower posterior rectum was diagnosed by digital examination, barium examination (Fig. 1) and colonoscopy (Fig. 2). Surgical local resection through the anus was carried out. The tumor was 15 mm in diameter, the cut section was yelowish-white (Fig. 3). HE staining of the tumor showed fine granules in the cytoplasm (Fig. 5). Using immunohistochemical study, the tumor cells were to be positively stained by S-100 protein (Fig. 6) and negatively stained by desmin.