大臼歯様外観を呈した盲腸顆粒細胞腫の1例

Granular Cell Tumor of the Cecum Resembling a Molar in Appearance, Report of a Case

要旨　盲腸に発生し大臼歯様外観を呈した顆粒細胞腫の1例を経験した．患者は57歳，男性．便潜血反応陽性の精査のため施行した注腸X線検査および下部消化管内視鏡検査で盲腸に径16mm大，表面平滑で黄色調の硬い大臼歯様の粘膜下腫瘍を認め，内視鏡的切除術を施行した．組織学的検討で，腫瘍は粘膜下層に主座を有し，HE染色で豊富な胞体内に好酸性顆粒を有する細胞から成り，免疫組織学的染色でS-100蛋白強陽性を示したため顆粒細胞腫と診断した．顆粒細胞腫の食道発生例にしばしばみられる大臼歯様外観は大腸では珍しく，その外観形成に至る病理組織学的検討および文献的考察を加えて報告した．

　 A case with granular cell tumor of the cecum was reported. The patient was a 57-year-old man who requested further examination because of his positive fecal occult blood test. A hemispherical protruded lesion in the cecum measuring 16 mm in diameter was disclosed by barium enema. Colonoscopy revealed a smooth-surfaced, hard and yellowish-colored submucosal tumor. It resembled a molar in appearance. Endoscopic polypectomy was performed. Histology with HE staining revealed the presence of eosinophilic granules in the cytoplasm of the tumor cells, and immunochemistry for S-100 protein was positive. According to these results, the diagnosis of granular cell tumor was established . It is uncommon that granular cell tumor in the colon shows a unique appearance as in this case. Histological investigation of our case revealed that this unique appearance is related to its growing process.