Colon melanosis

Introduction Colonic melanosis refers to a mucosal pigmentation disorder in which macrophages in the colonic lamina propria contain lipopolysaccharide, a rare, non-inflammatory, benign and reversible disease. The etiology of colonic melanosis is still unclear, but its incidence has increased in recent years, possibly with improved living standards, increased fat and protein intake, decreased cellulose intake, increased constipation, and rectocele, Rectal intussusception, slow colonic transmission and difficulty in defecation, and a large number of abuse of laxatives.

Cause

The etiology of colonic melanosis is still unclear, but its incidence has increased in recent years, possibly with improved living standards, increased fat and protein intake, decreased cellulose intake, increased constipation, and rectocele, Rectal intussusception, slow colonic transmission and difficulty in defecation, and a large number of abuse of laxatives. In particular, sputum laxatives are the main cause of melanosis, and sputum laxatives can enhance the activity and degeneration of macrophages. It can also damage the intestinal epithelial cells, especially the epithelial cells in the crypt. The epithelial cells are denatured, the nucleus is pyknotic, and finally the epithelial cells are necrotic, part of the necrotic epithelial cells enter the intestine and excreted with the feces, and another part of the degenerative colonic epithelial cells, whose membrane structure and disintegration products form so-called shedding The apoptotic bodies are trapped in the lamina propria and are phagocytosed by macrophages to form lipofuscin, which forms a melanosis. However, simple lipofuscin is not sufficient to explain why the color of blackness on a part of the dark mucosal colonic mucosa is so dark and typical. Therefore, it is believed that most of the steroids and their metabolites are dark brown, and they adhere to the surface of the epithelial cell structure that has been destroyed and disintegrated by macrophages, which aggravates the degree of blackening.

an examination

Related inspection

Colonoscopy fiber colonoscopy

MC diagnostic criteria:

1 Endoscopic colonic mucosa is black, brown or dark gray, the edges and early lesions are yellow or pink, with tiger skin striate, betel nut cut or patchy.

2 Histological examination showed that a large number of melanin-containing large mononuclear cells infiltrated and black cords were found in the intrinsic membrane, and other layers of the intestinal wall were normal.

Differential diagnosis

Hard fecal stone formed in the colon: symptoms of intestinal obstruction, due to frequent bowel movements, feces accumulate in the colon can form a hard fecal stone, or secondary megacolon, most of which affect growth and development, can also cause vaginitis or ascending infection Check the anus, common hip flat circle, shallow gluteal groove, no hole in the anus or only one trace, low deformity, the diagnosis can touch the blind end of the rectum. Fecal stone intestinal obstruction is a mechanical intestinal obstruction caused by intestinal feces, etc., and early diagnosis is difficult. In recent years, with the changes in dietary structure, the incidence rate has increased. In addition, with the aging of society, senile fecal stone colon obstruction is increasing. Older patients, due to the particularity of their pathophysiology, make the disease develop rapidly and the mortality rate is high. Many scholars have put forward the key points of early diagnosis and grasping the timing of surgery from the perspective of surgery.

Colonic vascular dysplasia: vascular dysplasia (angiodysplasia, AD) is beginning to be recognized in the colon. It is now known to be the most common cause of chronic intermittent or acute lower gastrointestinal bleeding in elderly people over 60 years old, and is also the cause of gastrointestinal bleeding. The most common cause of unknown.

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