Differential diagnosis of colorectal cancer

Colorectal cancer lacks symptoms in the early stages. When the tumor reaches 1 to 2 cm, due to the erosion of the tumor, the intestinal mucosa is stimulated by the foreign body of the tumor, and the secretion increases. Therefore, a small amount of mucus is discharged during defecation, mostly at the front end of the stool or attached to the outside of the stool. As the tumor grows, the secretion of mucus also increases. Sometimes, with the increase of intra-abdominal pressure due to flatulence or sudden coughing, mucus may flow out of the anus. What are the differential diagnoses of colorectal cancer?

1. The differential diagnosis of colon cancer is mainly based on inflammatory diseases of the colon, such as intestinal tuberculosis, schistosomiasis, granuloma, amebic granuloma, ulcerative colitis and colon polyposis, etc. The key points of clinical differentiation are the duration of the disease, parasites in stool examination, and the morphology and range of lesions found in barium enema examination. The most reliable differentiation is through colonoscopy and biopsy.
Periappendiceal abscess may be misdiagnosed as cecal cancer (colon cancer), but the blood count of this disease shows increased white bowel movement and neutrophils, without anemia, emaciation or other cachexia. A barium enema examination can confirm the diagnosis.
2. Rectal cancer is often misdiagnosed as hemorrhoids, bacterial dysentery, chronic colitis, etc., with a misdiagnosis rate of up to 60% to 80%. The main reason is that necessary examinations are not performed, especially digital rectal examination and colonoscopy.
3. Other colon tumors such as colorectal carcinoid are asymptomatic when the tumor is small, but may rupture when the tumor grows larger, resulting in symptoms that are very similar to colon adenocarcinoma. Malignant lymphoma originating in the colon has diverse lesion morphology and is often difficult to distinguish from colon cancer. Tissue smear biopsy should be performed to identify the two.