家族性大腸腺腫症における微小陥凹型大腸腺腫―実体顕微鏡・組織学的および形態計測学的検索

Minute Depressed Adenomas of the Large Intestine in Patients with Familial Adenomatous Polyposis (FAP) Dissecting Microscopical, Histological, and Morphometrical Studies

要旨　家族性大腸腺腫症26例の切除標本を実体顕微鏡下に観察し，任意に抽出した長径2mm以下の隆起型および陥凹型の微小大腸腺腫各100病変を系統的に観察した．一般に，陥凹型腺腫では1mm未満の病変は水平方向の発育を示したが，1mm以上の病変では隆起として捉えられるものが増加し，更に隆起型への移行像と考えられる病変も観察された．しかし，1mm以上でも著明な陥凹を示す特殊な腺腫もごくまれに存在していた．形態計測の結果から，絶対的陥凹は長径1mm未満の陥凹型腺腫では74％（23/31）と高率にみられたのに対し，1mm以上では22％（15/69）と低率であり，また粘膜筋板の隆起所見は1.0～1.5mmを超える病変で認められた．これらのことから，一般に微小陥凹型腺腫は徐々に通常の隆起型腺腫に移行すると考えられた．しかし，ごく一部のものは，比較的大型の陥凹型腺腫に成りうることが示唆された．

　Of the 26 large intestines with familial adenomatous polyposis (FAP) we systematically examined 100 colorectal polypoid and 100 depressed adenomas less than 2.0 mm in diameter. Generally, depressed adenomas less than 1.0 mm in diameter grew horizontally, while in those more than 1.0 mm in diameter their whole appearance showed vertical growth, and transitional types developing into polypoid adenomas were often seen among larger ones. However, adenomas which showed marked depression of their adenomatous crypts in spite of being more than 1.0 mm in diameter were rarely observed. By morphometrical analysis it was clarified that absolute depression was seen in 74% (23/31) of depressed adenomas less than 1.0 mm in diameter, and in 22% (15/69) of those more than 1.0 mm in diameter, and elevation of the muscularis mucosae was seen not in those of minute size, but in those more than 1.0 mm in diameter. From these findings it was suggested that most minute depressed adenomas would gradually develop into larger ordinary polypoid adenomas, but, among larger adenomas, exceptional ones might remain depressed.