Department of Gastrointestinal Surgery, Jiuyuan Hospital, Baotou, Inner Mongolia, China Endoscopy Department Yisheng Yu, Shunming Lu
Abstract】Objective: To investigate the etiology and clinical endoscopic features of colorectal melanosis. Methods: To summarize 40 cases of colorectal melanosis examined by colonoscopy in our hospital from 2005.7-2010.6 and analyzed retrospectively. RESULTS: All cases were diagnosed for the first time. Among the 40 cases of colorectal melanosis, 28 cases were older than 60 years old, accounting for 70%. There were 26 cases of constipation, accounting for 65%. Long-term oral laxatives were used in 24 cases, accounting for 60%. There were 16 cases without obvious oral laxatives. The percentage was 40%. Combined with ulcerative colitis 1 case accounted for 2.5%. Two cases of chemotherapy after radical colorectal cancer accounted for 5%. Conclusion: The main cause of colorectal melanosis is constipation and long-term use of anthraquinone-based laxatives, mostly in the elderly. Ulcerative colitis, postoperative chemotherapy and diarrhea may also be another cause of colorectal melanosis. Endoscopically: the mucosa of the large intestine is black, brown, or dark gray with a tiger skin pattern. Betel nut cut-like or patchy. It is localized or diffusely distributed. Yu Yisheng, Department of Surgery, Baotou Poverty Alleviation Hospital
【Key words】melanosis, constipation, laxative, endoscopic manifestation, carcinoma
Colonic melanosiscoli (Mc) refers to a mucosal pigmented lesion in which macrophages in the lamina propria of the large intestine contain lipid-brown material, and is a rare non-inflammatory benign reversible disease. More cases are reported abroad, but fewer in China. ｛In recent years, with the increase in the incidence of constipation and the widespread use of electronic colonoscopy, the detection rate in our population has gradually increased. The clinical and endoscopic characteristics of 40 cases of colorectal melanosis detected by colonoscopy from 2005.7-2010.6 in our hospital are analyzed as follows.
I: Clinical data and methods:
1 Our hospital endoscopy room from 2005.7-2010.6 colonoscopy found 40 cases of large intestine melanosis. There were 25 cases in men and 15 cases in women. The age was between 38-81 years old, and 28 cases were older than 60 years old, with an average age of 59.5 years. The clinical manifestations were: constipation, abdominal pain, diarrhea, abdominal distension, blood in the stool and sensation of anal drop. Among them, 24 cases accounted for 60% of the long-term oral laxative users, and the duration of medication was more than 3 months, with the longest duration reaching 5 years. There were 16 cases without obvious oral laxatives. The percentage was 40%.
2Methods: Using Fujiren ER-250 electronic colonoscopy, the luminal approach was used to reach the ileocecal region, and pathological tissue biopsies were taken in all cases (including polyps).
3 Results: endoscopic colon melanosis: the colonic mucosa had varying degrees of pigmentation, and the mucosa was black, brown, and dark gray with a tiger skin pattern. Betel nut cut-like or patchy, which was distributed in the whole colon in 18 cases accounting for 45%, the left hemicolectomy and transverse colon in 12 cases accounting for 30%. The right hemicolon accounted for 25% in 10 cases. According to the depth of pigmentation, there were three degrees of pigmentation: degree I, light black-brown, similar to leopard skin, asymmetric creamy white spots in the lymphoid follicular epithelium, and faintly visible mucosal vascular texture. The lesions mostly invade the rectum, cecum or a section of intestinal mucosa in the colon, and the scope of the affected colonic intestinal segment is small, and the demarcation line between the pigmented intestinal mucosa and the non-pigmented intestinal mucosa is unclear. Grade II, dark purple-brown, with streaks of milky white mucosa between the dark black-brown mucosa, mostly in the left half of the colon or a section of the colon, with many mucosal vessels, which should not be seen, and the demarcation of the pigmented intestinal mucosa is clearer. Degree III, dark black-brown, with fine milky-white linear or speckled mucosa between dark black-brown mucosa, with unclear mucosal vascular network, mostly seen in the whole colon. In this group of cases, 10 cases of first-degree colorectal melanosis accounted for 25%. In this group, 14 cases of degree II colorectal melanosis accounted for 35%. The 16 cases of Ⅲ degree colorectal melanosis accounted for 40%. Among them, 24 cases accounted for 60% of long-term oral laxatives, 16 cases without obvious oral laxatives. 40%, 6 cases of combined polyps accounted for 15%, and 1 case of cancer accounted for 2.5%. Combined with ulcerative colitis 1 case accounted for 2.5%. 2 cases of chemotherapy after radical colorectal cancer accounted for 5%, 1 case of combined diarrhea accounted for 2.5%, combined with 6 cases of polyps, there are 4 cases of colorectal melanosis III.
Pathological histology.
The mucosal biopsy of colorectal melanosis showed edema of the lamina propria, a large number of large mononuclear cells containing melanin infiltration and melanin deposition, and other levels of the intestinal wall were normal. The pathology of 6 cases of combined polyps, 3 cases of inflammatory polyps, 2 cases of adenomas and 1 case of adenocarcinoma, were confirmed as adenocarcinoma cases underwent radical colon cancer surgery, and the pathology of postoperative specimens was consistent with the diagnosis of biopsy.
4 Conclusion: The main cause of colorectal melanosis is constipation, and long-term use of anthraquinone-based laxatives, including senna, nux vomica pills, aloe vera preparations, fruit guide tablets, etc., are mostly seen in the elderly, but laxatives are not the only factor in the formation of colorectal melanosis, and some patients without a history of constipation and oral laxatives can also develop colorectal melanosis, ulcerative colitis and chronic diarrhea may be another cause of colorectal melanosis. Patients after radical colorectal cancer surgery may also be the cause of colorectal melanosis. And there is a close relationship between colorectal melanosis and colorectal tumor, and the heavier the melanosis, the greater the chance of tumor formation, whether there is a causal relationship, need further research. Therefore, although colorectal melanosis is a benign reversible disease, it often has the tendency to combine with cancer, and it is necessary to review colonoscopy regularly in clinical practice.
II: Discussion
The main symptoms are constipation, abdominal pain, abdominal distension, and anal drop sensation. It may be related to pigmented inflammation and stimulation of the enteric nervous system. Its etiology, pathogenesis, and source of pigmentation are not clear, and it is thought to be related to long-term oral laxatives, and ulcerative colitis and diarrhea are also related to the formation of melanosis. Because it is accompanied by colonic tumors, it is gradually gaining attention. In clinical work, we should clarify the following relationships.
A relationship between colorectal melanosis and laxatives: long-term abuse of oral laxatives in constipated patients is currently recognized as the main cause of colorectal melanosis. Among them, the pathogenic effect of anthraquinones has basically reached a consensus, and the possible mechanism is that various stimulating factors induce apoptosis of colonic epithelial cells, so that the colonic surface cells are damaged, and the apoptotic cell vesicles and cell fragments produced are increased by the intrinsic layer of the lamina propria macrophages, forming lipid brown or other pigments, and with the increase of measurement, macrophages continue to gather to eventually form colonic melanosis ｛2｝The data of our hospital show that 24 This is supported by a history of oral laxatives for about 3 months to 5 years. Therefore, in clinical work, avoid the use of anthraquinones as much as possible, add full gastrointestinal motility drugs if necessary, and perform colonoscopy to rule out colorectal melanosis in long-term laxative users.
B relationship between colorectal melanosis and colorectal cancer and polyps: patients with colorectal melanosis are often accompanied by cancer or polyps, domestic and foreign literature reported that 4.8%-5.9% of resected specimens of colorectal cancer are accompanied by melanosis, or melanosis, colon polyps combined with carcinoma, data show that there is a certain relationship between melanosis and carcinoma and polyps, and colorectal melanosis with adenocarcinoma is a common view ｛3｝ long-term In addition, some active ingredients of laxatives have potential toxicity and carcinogenic effects in in vitro tests, and there are 6 cases of polyps and 1 case of carcinoma in this group of patients, suggesting that colorectal melanosis is easily accompanied by colon polyps and colon cancer, and the heavier the colorectal melanosis, the greater the chance of combined colon tumor. The more severe the colorectal melanosis, the greater the chance of combined colon tumor. Therefore, we should be alert to the existence of bowel cancer while detecting colorectal melanosis, and colonoscopy should be performed regularly.
C colorectal melanosis and gender, the relationship between age: According to the literature, most experts believe that colorectal melanosis and age have a close relationship, the prevalence of middle-aged and elderly people, more than 60 years old accounted for 64.6% of the special attention to middle-aged and elderly patients, should be for the cause. Active treatment with anthraquinones as little as possible to prevent the occurrence of colorectal melanosis. At the same time, we also found that due to the lack of knowledge about constipation, people do not go to the regular hospital for treatment, but blindly use bowel cleansing drugs, which can also lead to the occurrence of colorectal melanosis.
D colorectal melanosis and other factors: Although long-term use of laxatives plays a major role in the formation of colorectal melanosis, domestic data reported that inflammatory bowel disease can also be combined with colorectal melanosis. 15 out of 18 cases of ulcerative colitis, in which patients did not take laxatives, combined with colorectal melanosis, suggesting that ulcerative colitis may be another cause of hyperpigmentation besides laxatives ｛4｝. In addition, it has been reported that chronic diarrhea can be combined with colorectal melanosis, so whether chronic diarrhea is a factor in the pathogenesis of the disease is also of concern to clinicians. In our group, two post-radical colorectal cancer patients with no history of oral laxatives also developed colorectal melanosis, which may be related to postoperative chemotherapy. It may be related to the action of chemotherapeutic drugs and other substances on intestinal mucosa, and postoperative chemotherapy for colorectal cancer should be alert to colorectal melanosis.
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Authors Yu Yisheng, Department of Gastrointestinal Surgery, Jiuyuan Hospital, Baotou, Inner Mongolia, China
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