@article{oai:niigata-u.repo.nii.ac.jp:00006537,
 author = {Ohta, Tamaki},
 issue = {1},
 journal = {Acta medica et biologica, Acta medica et biologica},
 month = {Mar},
 note = {One hundred and six lesions of mucosal prolapse syndrome (MPS) of the rectum were examined in regard to macroscopic type, location, histological stage and mucosal thickness in order to analyse the natural history of the disease. Sixty-six lesions belonged to the polypoid type. In 61 of these, the distance from the dentate line was able to be verified. Fifty-one lesions (83.6%) occurred in the lower rectum within 2cm proximal to the dentate line. Forty-six of the 66 lesions (69.7%) showed a low-grade fibromuscular stage, but no high-grade fibromuscular stage. The thickness of polypoid mucosa excluding the muscularis mucosae which could be measured in 27 of the 66 lesions had a mean of 1.96 mm at the top area, and 0.75 mm in the surrounding area. Twenty-five lesions belonged to the flat type. Twenty-four of these were located within 2cm from the dentate line. Seventeen (68.0%) belonged to low-grade fibromuscular stage, 7 (28.0%) to the vascular stage and 1 (4.0%) to the high-grade fibromuscular stage. The mucosal thickness of 15 lesions averaged 0.54 mm. On the other hand, there were 21 ulcerative type lesions, with the distance from the dentate line verified in 20 of them. Thirteen lesions (65.0%) were located within 2-17 em proximal to the dentate line. They were distinct from the other types in their higher incidence of fibromuscular stage (95.2%), particularly of a highgrade stage (47.6%). The mucosal thickness of 9 lesions was a mean of 0.78 mm in the ulcer-marginal area and 0.58 mm in the surrounding area. In both the polypoid and ulcerative types, arteries showed a thickening of the media and intima in the submucosa. These findings were most conspicuous in the ulcerative type. It is concluded that MPS initially occurs in flat types as a result of reversible mucosal prolapse, and then either changes into a polypoid (glandular hyperplasia) type-especially near the dentate line-by a process of non-transmural rectal prolapse, or changes into an ulcerative type especially within a distance of 2-17 cm proximal to the dentate line by the process of transmural rectal prolapse which causes severe ischemic change.},
 pages = {33--43},
 title = {Mucosal Prolapse Syndrome of the Rectum : Correlation between Macroscopic Type and Location in a Discussion on Its Natural History},
 volume = {41},
 year = {1993}
}