Low-grade mucinous neoplasm of appendix

Low-grade mucinous neoplasm of the appendix is ​​a particularly rare appendix disease. Its symptoms are very similar to those of appendicitis and can be easily confused. Therefore, when patients experience pain in the right lower abdomen of the appendix, they must not be careless and think that it is appendicitis. However, if low-grade mucinous tumors of the appendix are discovered and treated in the early stages, they can be cured. Next, let us learn more about this disease.

1. Concept

Appendiceal mucinous neoplasm is a rare disease, accounting for 0.2%-0.7% of appendectomies. Appendiceal mucinous tumors are divided into low-grade mucinous tumors and mucinous adenocarcinomas based on the nuclear atypia of epithelial tumor cells and the degree of epithelial structural changes. Low-grade mucinous tumors of the appendix are borderline or low-grade malignant tumors. Tumor cells can easily fall off into the abdominal cavity to form pseudomyxoma peritonei, causing implantation dissemination and recurrence.

2. Symptoms

History of chronic intermittent right lower abdominal pain; physical examination revealed an oval mass with a smooth surface and no adhesions around it;

3. Causes

The submucosal layer of the appendix is ​​rich in lymphoid tissue. Once tumor cells or mucus invade the submucosal layer, it will cause hyperplasia of the lymphoid tissue and cause significant narrowing of the appendix cavity. There are many microorganisms in the appendix cavity, and infection will occur once the cavity is narrowed.

4. Diagnosis

X-ray barium meal may show bird's beak sign; B-ultrasound examination may show localized dark area. CT scans showed an eggplant-shaped cystic mass and nodules on the cyst wall in the right iliac fossa; calcification was seen in the cavity or on the cyst wall; the boundaries of the lesion were unclear, exudation might be present nearby, and the density of the fat spaces might be increased. In case of tumor perforation or rupture, solid components can be seen floating in the high-density peritoneal pseudomyxoma or ascites. In case of implantation and metastasis, nodular protrusions can be seen in the peritoneum, mesentery, diaphragm, abdominal wall, ovaries, etc., the edges of the liver and spleen show scallop-like changes, and sand-like calcifications can be seen in the metastatic lesions.

5. Hazards

The most serious and common complication is appendix perforation caused by tumor tissue and tumor cells implanting on the peritoneum, forming pseudomyxoma peritonei. If not removed in time, symptoms such as compression, adhesion and obstruction may occur.

6. Treatment

According to the international consensus, cytoreductive surgery + hyperthermic intraperitoneal chemotherapy is required, including appendectomy or right hemicolectomy + total omentectomy or splenectomy + bilateral adnexectomy and hysterectomy as appropriate + pelvic peritonectomy + lateral peritoneum and double diaphragm peritonectomy + continuous hyperthermic intraperitoneal chemotherapy during and early after surgery. For patients with larger tumors and malignant transformation, ileocecal or right hemicolectomy is required. It is possible to achieve a complete cure for patients in the first clinical stage through the above-mentioned surgical treatment, but it is often impossible to achieve a complete cure for patients in the late stage.

7. Differentiation from appendicitis

Patients are easily misdiagnosed as appendicitis clinically. When appendicitis occurs, the upper limit of the outer diameter is 6 mm. If it exceeds 15 mm, it is more likely to be a mucinous tumor. In simple appendicitis, the appendix is ​​enlarged, with less mucus, lower density, and enteroliths at the root, but there will be no calcification inside the cyst or on the cyst wall.