Histological features of rectal adenocarcinoma

Rectal cancer is mainly adenocarcinoma, which mainly includes columnar cells, mucus-secreting cells and undifferentiated cells. It is further classified into tubular adenocarcinoma and papillary adenocarcinoma, accounting for 75% to 85% of all adenocarcinomas, followed by mucinous adenocarcinoma, accounting for 10% to 20% of all adenocarcinomas.

1. Tubular adenocarcinoma

The histological characteristic of tubular adenocarcinoma is that the cancer cells are arranged in glandular ducts or alveoli. According to the degree of differentiation, it can be further divided into poorly differentiated adenocarcinoma, moderately differentiated adenocarcinoma, and well-differentiated adenocarcinoma.

2. Papillary adenocarcinoma

The histological characteristic of papillary adenocarcinoma is that the cancer cells are arranged in papillary structures of varying sizes, and the central cord of the nipple is a small amount of vascular stroma.

3. Mucinous adenocarcinoma

The histological characteristics of mucinous adenocarcinoma are that the tumor is composed of cancer cells that secrete mucus, and there is a large amount of mucus in the cancer tissue. This type of cancer is highly malignant and has a poor prognosis.

4. Signet ring cell carcinoma

The histological feature of signet ring cell carcinoma is that the cancer lesions are composed of diffuse signet ring cells, with darker nuclei stained on one side of the cytoplasm, resembling a ring. This type of carcinoma is more malignant than mucinous adenocarcinoma and has a very poor prognosis.

5. Undifferentiated carcinoma

The histological characteristics of undifferentiated carcinoma are that the cancer cells are diffuse and in sheets or clusters, without forming glandular duct structures, and the cells are small, irregular in shape, and arranged in disorder. This type is the most malignant and has the worst prognosis.