roded Polypoid Hyperplasia of the Rectosigmoid Colon: Report of 2 cases with special reference to its relation to mucosal prolapse syndrome

Polypoid prolapse of mucosal folds can occur at various sites and in various conditions predominantly associated with strain during defecation. There are two well known types of mucosal prolapse syndrome(MPS), the inflammatory cloacogenic polyp(ICP) and the mucosal redundant polyp associated with diverticular disease(N4RPD). ICP is a mucosal prolapse of the anorectal junction and MRPD is a proximal analogue involving the sigmoid colon. We experienced two cases of eroded polypoid hyperplasia(EPH) of the rectosigmoid colon which manifested as a huge gyriform mass simulating the gross features of gastrointestinal lymphomas or other malignant tumors. The EPH consisted of confluent polypoid mucosal folds with rolled-up submucosa to form stalk, The polypoid lesion represented hyperplastic epithelium, erosion of the mucosal surface and congestive vascular ectasia of lamina propria and submucosa. To explain the whole morphologic features, the initial phenomenon should be the mucosal prolapse. Vascular stretching with ischemic erosion of the mucosal surface and compensatory epithelial hyperplasia ensue as the result. The ominous endoscopic and gross features of EPH should be kept in mind to avoid erroneous radical surgery.

Clinicopathologic comparison of eroded polypoid hyperplasia and solitary rectal ulcer syndrome

We experienced two unusual cases of tumor-like polypoid lesions involving the rectosigmoid colon. They could not be readily classified into any well known polypoid tumors of the rectosigmoid colon, but appeared to have some similarities to the previously documented "eroded polypoid hyperplasia (EPH)". A collective review of our seven cases of solitary rectal ulcer syndrome (SRUS), which proved to be due to paradoxically over-reactive muscle tone of the puborectalis, was performed, and clinicopathologic comparisons between EPH and SRUS were carried out. They shared histopathologic characteristics such as vascular congestion, crypt hyperplasia, and eroded surface, but they were different from each other in clinical symptoms, location of lesions and gross features. Furthermore, in one EPH case there was an altered much profile which was similar to that seen in SRUS and complete rectal prolapse. Conceivably, the pathological features of both EPH and SRUS were thought to have a possible connection with mucosal prolapse syndrome (MPS). Considering that MPS is a group of diseases encompassing SRUS and the related disorders of the colorectum and the anus, it is speculated that EPH of the rectosigmoid colon might be the proximal analogue of SRUS, a mucosal prolapse of the more distal colon.