中咽頭の超・微小癌の2例

Extremely Minute Squamous Cell Carcinoma in the Middle Pharynx, Report of Two Cases

要旨　咽頭領域における2mm以下の扁平上皮癌の2症例を提示する．〔症例 1〕69歳男性，早期食道癌に対するEMR後のfollow up症例．中咽頭後壁に径1.8mmの発赤面を認めた．拡大内視鏡観察にてIPCL（intra-epithelial papillary capillary loop）パターン分類IPCL type V-1の所見を認め，内視鏡的に上皮内癌を強く疑った．透明キャップ法（EMR-C）によるEMRを行った．病理学的に扁平上皮癌（CIS）と診断された．〔症例2〕56歳男性，早期胃癌の症例．中咽頭後壁に径1mmの微小発赤面を認めた．拡大内視鏡観察でIPCLパターン分類IPCL type V-1の所見を認め，内視鏡的に上皮内癌を強く疑った．生検鉗子を用いて完全生検を行った．生検材料は病理学的に扁平上皮癌と診断された．いずれの症例でも，NBI（narrow band imaging system，プロトタイプ，オリンパス）を併用した拡大内視鏡は，IPCLの観察に有用であった．このような超・微小癌での病変の同定は，治療を著しく低侵襲化することができ，患者利益に直結すると考えている．

　〔Case 1〕　A 69-year-old male. A single 1.8 mm reddish lesion was detected during endoscopic examination following initial EMR in the esophagus five years previously. Magnifying endoscopy revealed characteristic changes of IPCL for carcinoma in situ (IPCL type V-1). The narrow band imaging system (NBI, prototype, Olympus medical systems) is extremely useful to demonstrate capillary changes better. The minute lesion was resected using the EMR-Cap technique. Histological analysis revealed that the resected specimen included a single 1.8 mm carcinoma.

　〔Case 2〕　A 56-year-old male. A 1 mm lesion was observed as a minute flare on the mucosal surface in the middle pharynx. In this case, magnifying endoscopy also clarified proliferation of micro-vessels (IPCL type V-1) in the 1 mm tiny area. Forceps biopsy was carried out to resect the whole lesion as a complete biopsy specimen. The pathological diagnosis for the biopsy specimen was squamous cell carcinoma.