食道顆粒細胞腫の表面に0-IIc型早期癌を認めた1例

Type 0-IIc Early Esophageal Cancer Coexisting with Esophageal Granular Cell Tumor, Report of a Case

要旨　上腹部痛を主訴として来院した71歳女性に胃潰瘍と2cm大の食道粘膜下腫瘍（SMT）が発見された．SMT頂部のびらんからの生検で低分化型扁平上皮癌が証明され，SMTとともに内視鏡的に切除した．切除標本の病理組織学的検索により，食道顆粒細胞腫の表面に存在する0-IIc型早期癌が証明された．食道顆粒細胞腫は，その上皮にpseudoepitheliomatous hyperplasiaと呼ばれる過形成を生じ，扁平上皮癌と誤診されることがある．本症例もその可能性を考慮したが，免疫組織学的にp53，Ki-67が陽性となり，食道癌と診断した．食道顆粒細胞腫はpseudoepitheliomatous hyperplasiaの可能性に十分配慮しつつ，慎重な診断，治療が必要であると考えられた．

　A 71-year-old female visited our hospital for further examination of an esophageal tumor. Endoscopy showed a protruding lesion with a smooth surface in the lower esophagus. The top of the tumor was eroded and unstained by iodine staining. Biopsy specimens of the lesion contained poorly differentiated squamous cell carcinoma. The tumor was resected endoscopically. The resected specimen revealed superficial carcinoma over a submucosal granular cell tumor. Microscopic findings showed squamous cell carcinoma had involved the lamina propria. Below the carcinoma, a granular cell tumor existed. Using immunohistochemical study, the carcinoma cells were to be positively stained by p53, and granular cell tumor cells were to be positively stained by S-100 protein. It is a known fact that the pseudoepitheliomatous hyperplasia of the overlying esophageal epithelium induced by granular cell tumor may lead to incorrect diagnosis of well-differentiated squamous cell carcinoma. In this case, this possibility was sufficiently considered, but immunohistochemically, it proved to be a carcinoma. In light of this fact, granular cell tumor must be diagnosed only after careful consideration of this phenomenon.

　1) Department of Radiology, Gifu University School of Medicine, Gifu, Japan

　2) Department of Laboratory Medicine, Gifu University School of Medicine, Gifu, Japan

　3) Sunrise Clinic, Gifu, Japan