Benign tumors of the small intestine

The International Histological Classification of Intestinal Tumours (WHO, No. 15, Geneva, 1981) identifies the following benign tumours of the small intestine:

1. epithelial;
2. carcinoid;
3. non-epithelial tumors.

Epithelial tumors of the small intestine are represented by adenoma. It has the appearance of a polyp on a stalk or on a broad base and can be tubular (adenomatous polyp), villous and tubulovillous. Adenomas in the small intestine are rare, most often in the duodenum. A combination of adenoma of the distal ileum with adenomatosis of the colon is possible.

Carcinoids arise in the crypts of the mucous membrane and in the submucosal layer. The epithelial covering is initially preserved and then often ulcerates. Carcinoid is represented by small cells without clear boundaries with uniform round nuclei. Tumor cells form wide layers, cords and cells. Sometimes a small number of acinar and "rosette-shaped" structures can be found.

Carcinoids are divided into argentaffin and non-argentaffin. Argentaffin carcinoids are characterized by the presence of eosinophilic granules in the cytoplasm of cells, which are stained black with the argentaffin reaction (Fontana method) and brown-red with the diazo method. Argentaffin and chromaffin reactions (granules are stained brown when treated with chromic acid or dichromate) of carcinoids are caused by the presence of serotonin in them; in these cases, the carcinoid is clinically expressed as carcinoid syndrome. Non-argentaffin carcinoids do not give these reactions, but are similar to argentaffin carcinoids in their histological structure.

Nonepithelial tumorssmall intestine are also extremely rare, they are represented by tumors of muscle, nervous, vascular, adipose tissue. Leiomyoma has the appearance of a node in the thickness of the intestinal wall, more often in the submucosal layer, without a capsule. The tumor is represented by elongated spindle-shaped cells, sometimes their nuclei are located in a palisade. Leiomyoblastoma (bizarre leiomyoma, epithelioid leiomyoma) is built of rounded and polygonal cells with light cytoplasm, devoid of fibrils. Being a predominantly benign tumor, it can metastasize. Neurilemmoma (schwannoma) is an encapsulated tumor with a palisade-shaped arrangement of nuclei and sometimes complex organoid structures. With secondary changes, cystic cavities are formed. It is usually located in the submucosal layer. Lipoma is an encapsulated node represented by fat cells. It is usually located in the submucosal layer. Sometimes it reaches large sizes and can cause intussusception and intestinal obstruction.

Hemangioma and lymphangioma are usually congenital and can be single or multiple. Common intestinal hemangiomas are manifestations of Rendu-Osler-Weber and Parkes-Weber-Klippel syndromes.

Symptoms. Benign tumors of the duodenum are initially asymptomatic for a long time and are discovered accidentally - during an X-ray examination of the duodenum or during a gastroduodenoscopy undertaken for another reason, or prophylactically - during a medical examination. When the tumor reaches a large size, it usually manifests itself with symptoms of mechanical obstruction of the small intestine or, if the tumor disintegrates, intestinal bleeding. A large tumor can sometimes be palpated. In some cases, when the tumor is localized in the area of the large papilla (Vaters) of the duodenum, one of the first symptoms may be obstructive jaundice. Benign tumors of the duodenum can be single or multiple.

During X-ray examination (X-ray examination is especially valuable under conditions of artificial hypotension of the duodenum), one or more filling defects are determined; the contours of a benign tumor are usually clear and smooth (unevenness occurs when the tumor becomes necrotic). Endoscopic examination, supplemented by targeted biopsy, in many cases allows us to accurately determine the nature of the tumor and conduct a differential diagnosis with cancer and sarcoma of the duodenum.

Treatment of benign tumors of the duodenum is surgical. Tumors localized in the area of the major papilla (Vaters) of the duodenum are excised with subsequent implantation of the common bile and pancreatic duct into the duodenum. When removing polyps in the area of the major papilla of the duodenum (Vaters), as evidenced by the data of V. V. Vinogradov et al. (1977), in half of the cases improvement occurs immediately after the operation, in the remaining cases - within a few months after it. Recently, it has become possible to remove small polyp-like tumors of the duodenum during duodenofibroscopy.

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