食道小扁平上皮癌の拾い上げ診断の現況―通常観察とヨード染色法

Present State of Endoscopic Detection of Minute and Small Esophageal Squamous Cell Carcinoma：Conventional Observation and Iodine Staining

要旨　現在，微小食道癌や小食道癌についての明確な定義はない．筆者らは，腫瘍径が10mm以下は小食道癌，5mm以下は微小食道癌と仮に定義した．現在までに内視鏡的切除（ER）を施行した796例の食道表在癌のうち小食道癌は68例であり，微小食道癌は8例であった．微小，小食道癌の診断に関して，28例（36.8％）は通常観察で診断されたが，48例（63.2％）はヨード染色により発見されている．肉眼型に関しては0-IIb 28例（36.8％）と0-IIc 33例（43.4％）で61例となり，全体の80.2％を占めていた．肉眼型と深達度に関しては，0-IIa，0-IIbでは全例T1a-LPMまでにとどまっていたが，0-IIcで辺縁隆起を伴う病巣や隆起型ではT1a-MM以深の浸潤を認めた．

　At present there is no international definition of small esophageal cancer. We defined small esophageal cancer as that less than 10mm and minute esophageal cancer as that less than 5mm in size.

　Until now, 796 cases of superficial esophageal cancer have been treated in our institution by Endoscopic resection. Among them 68cases were small esophageal cancers and 8 cases were minute esophageal cancers.

　We analyzed small and minute esophageal cancer, concerning its clinical date, diagnosis, clinicopathological findings according to the Japanese Guide lines for Clinical and Pathologic Studies of the esophagus.

　Concerning the depth of invasion, all cases of 0-IIb were limited to the lamia propria mucosa（T1a-LPM）, while tumors containing elevated or protruding components seemed more invasive.

　As for endoscopic diagnosis, 28 cases of minute and small esophageal cancer were detected by conventional observation. However, 48cases（63.2％）needed iodine staining for their lesions to be detected by endoscopic examination.

　Concerning the gross findings, type 0-IIb（28cases:36.8％）and 0-IIc（33cases:43.4％）lesions occupied 80.2％ of all these lesions.

　Concerning the depth of invasion, all cases of type 0-IIa or 0-IIb were limited within a lamina propria of the mucosa（T1a-LPM）.

　However tendency was recognized for 0-IIc type tumors containing marginal elevation or 0-I of protruding component to be more invasive deeper than T1a-MM type tumors.