Clinicopathological features of phlebosclerotic colitis.

Phlebosclerotic colitis (PC) is a rare chronic ischemic colitis caused by venous reflux disorder. It is also called idiopathic mesenteric phlebosclerosis (IMP) due to unknown etiology. The disease is characterized by sclerosis of mesenteric vein and its branches as well as fibrosis, hyaline degeneration, calcification, thickening of colon wall. CT images show linear calcification in the colon mucosa as well as mesenteric vein and its branches. Endoscopy shows purple-blue mucosa with multiple erosion and ulceration. Microscopically, the colon mucosa shows fibrosis, hyaline degeneration and extensive thickening. The most characteristic lesion is fibrosis and calcification of the vessels especially the veins. Arteries in all layers of colon are also involved, but the injury is significant mild and less. We collected 10 confirmed patients from 2012 to 2019 in our hospital, studied their clinical histories in detail, summarized typical changes of CT images, endoscopic images and pathological sections, and made a detail follow-up. In addition to typical pathological changes, we also found that gardenia or its metabolites may be the pathogenic factor. Probablely, geniposide which is metabolized to genipin by β-glucosidase of colon flora in proximal colon, results in venous sclerosis. PC is occult onset and irreversible without special symptoms in the early stage, but it will also be stable after removing the pathogenic ingredient. Most of patients may be "cured" by appropriate conservative medication and stopping drinking. Contrary, inappropriate surgery may "trigger" the acute ischemia which results in obstruction rapidly. We hope our colleagues pay attention to the unique lesion and make early diagnosis and treatment.