直腸の粘膜脱症候群（mucosal prolapse syndrome）の病理形態学的再検討

Histopathological Reevaluation On Mucosal Rrolapse Syndrome of the Rectum

要旨　直腸の粘膜脱症候群（mucosal prolapse syndrome；MPS）35症例を用いて，その組織像の経時的変化，肉眼型分類および各肉眼型の特徴と移行について検討した．MPS組織像の特徴は，初期に血管の変化（血管期）として現れ，次いで特有とされる線維筋症（線維筋症期）として表現された．病巣の肉眼型は平坦型（8病巣），隆起型（18），潰瘍型（7），深在囊胞性大腸炎型（CCP）（3）に分類された．隆起型は直腸末梢部に70％以上と好発し，潰瘍型はすべてそれより上部の直腸に発生した，顕微鏡的CCP型は潰瘍型に43％，隆起型に11％みられ，肉眼的CCP3例は前駆潰瘍を伴っていなかった．平坦型MPSは直腸末梢部のものと，それより上方のものとで病態に差がみられた．MPSは直腸内での発生部位によって，その形態や推移を異にし，隆起型と潰瘍型では病態が全く異なることを明らかにした．

　Thirty-five cases (36 lesions) of mucosal prolapse syndrome (MPS) of the rectum were studied with special reference being made to histological change with time, macroscopic classification, and macroscopic characteristic and transformation of each gross type.

　The characteristic microscopic changes first occurred in the capillaries beneath the surface epithelium (vascular lesion) and then in abnormal proliferation of fibromuscular tissue (fibromuscular lesion).

　The macroscopic type was divided into flat MPS (8 lesions), polypoid MPS (18), ulcerative MPS (7) and colitis cystica profunda (CCP; 3 lesion). The polypoid type occurred predominantly (70％) in the terminal rectum, while the ulcerative type all in the rectum upper than the terminal. The microscopic CCP was found in 43％ of the ulcerative MPS and in 11％ of the polypoid MPS. Three cases of macroscopic CCP were not asociated with preceding ulcers in the lesion.

　The flat type in the terminal rectum was morphologically different from the flat type in the upper rectum.

　It is concluded that MPS is different in morphology and its outcome according to the locations of the lesions and that the polypoid type and the ulcerative type are quite different in behavior.