Delayed diagnosis of ascending colon mucinous adenocarcinoma with local abscess as primary manifestation: Report of three cases.

Background: Colorectal mucinous adenocarcinoma is a distinct subtype of colorectal adenocarcinoma that is not sensitive to chemotherapy and radiotherapy, and its prognosis is worse than that of nonmucinous adenocarcinoma. Early diagnosis and aggressive surgical treatment may be the key to improving the prognosis of patients. Ascending colon mucinous adenocarcinoma with the primary manifestation of a local abscess caused by non-intestinal perforation has never been reported. Moreover, since the lumen of the ascending colon is large, and early stage ascending colon cancer lacks typical clinical manifestations, the diagnosis may be delayed easily. We herein report three cases of delayed diagnosis of colorectal mucinous adenocarcinoma.

Case Summary: We present three patients (two females and one male) with mucinous ascending colon mucinous adenocarcinoma with the primary manifestation of a local abscess (the right area of the lumbar spine, right groin, and lower right abdomen) caused by non-intestinal perforation. At the initial clinical visit, the common causes of those abscesses, including spinal tuberculosis and urinary tract infection, were excluded. The treatment of the abscess was through an incision and drainage. However, the source of the abscess was not made clear, which led to an abscess recurrence and a delayed diagnosis of colorectal mucinous adenocarcinoma. After the patients were referred to our hospital, a definitive diagnosis of ascending colon mucinous adenocarcinoma was made with the help of tumor markers and colonoscopic findings. Because of the delayed diagnosis of the disease, two patients (case 1 and case 2) missed the chance of surgery due to disease progression and died in a short follow-up period. Only case 3 underwent radical surgery for the tumor in the right colon and partial abdominal wall resection and achieved a better prognosis.

Conclusion: Abscesses in the right area of the lumbar spine, right groin, or right lower quadrant caused by non-intestinal perforation as the primary clinical manifestation of ascending colon mucinous adenocarcinoma are extremely rare. Mucinous adenocarcinoma of the ascending colon may be one of the causes of such abscesses. Performing colonoscopy as soon as possible is of great significance in the diagnosis and treatment of the disease.