Overview of Colorectal Choriadenoma
Colorectal villous adenoma, also known as papillary adenoma, is a kind of adenoma with great cancerous rate, and the villous component accounts for more than 80% of the total, with a lower incidence, which is regarded as precancerous lesion. It occurs mostly in the elderly, more in men than women, and preferably occurs in the rectum and the lower part of the sigmoid colon.
Etiology
The etiology is not clear, some scholars believe that papillary adenoma is well-differentiated papillary carcinoma, some scholars believe that true papillary adenoma rarely occurs.
Symptoms
Clinical manifestations are nonspecific, the main symptoms are frequent bowel movements and discharge of large amounts of mucus, which can be easily misdiagnosed as enteritis or dysentery. And there is incomplete defecation and a sense of urgency and heaviness, and bleeding is often in the late stage. Prolonged blood in stool and diarrhea may cause systemic symptoms such as hypokalemic arrhythmia, weakness, emaciation and fatigue.
Examination
1. Anal diagnosis
Low and middle level rectal villous adenomas can be palpated by anal diagnosis, but in early stage and when the adenomas are small, they are easy to be missed because of their soft texture.
If the tumor is found to have no tip, uneven texture, abnormal hard nodules, infiltration at the base, large tumor, or the tumor is involved with the intestinal wall during palpation, it should be alerted to the possibility of carcinoma.
2. Imaging examination
For patients who cannot complete the whole colon examination with fiberoptic colonoscopy, barium enema X-ray examination can be an important supplementary means of examination.
3. Endoscopy
Microscopy shows obvious papillary or villous structure, usually without clitoris. Fiber colonoscopy should be done for high-grade adenoma, and biopsy can be taken on the surface and base of the tumor, but the positive biopsy rate is generally low.
4. Pathologic examination
It is velvety or granular elevation, the majority of which is wide base, non-tibial type, with soft texture; a small part of it may have a tip, with large mobility. Microscopic histological morphology shows a papillary component centered on blood vessels and connective tissue with peripheral branches, with a single layer of columnar or pseudocomplex epithelium and cup cells on the surface, and fewer glandular components.
Diagnosis
The diagnosis can be confirmed on the basis of the patient’s medical history, clinical manifestations, and anal diagnosis, barium enema contrast, endoscopy and pathologic examination.
Treatment
Surgical treatment is preferred, local excision or extended excision.
1. Transanal or transsacrococcygeal local excision is suitable for the distance from the anal verge is less than 8 cm, and the whole piece of excision including the adenoma, including the surrounding normal mucosa of 0.5-1 cm is carried out. Transanal endoscopic microsurgery (TEM) is a minimally invasive surgical procedure.
2. Transanal endoscopic resection is suitable for non-tibial adenomas with a diameter of less than 1 cm, which is not limited by the lesion site and operative field, and has a low rate of postoperative complications and tumor recurrence.
3. Transabdominal or transperitoneal resection It is suitable for adenomas with a diameter of more than 1 cm and a distance of more than 8 cm from the anal verge.
4. Intestinal segmental resection is suitable for resection of multiple adenomas in the intestinal segment of the diseased intestinal canal.