Aim: We aimed to clarify the clinicopathological features of poorly differentiated colorectal adenocarcinomas and to define two subtypes of these adenocarcinomas.
Patients and methods: We enrolled 78 patients, who had undergone surgery for poorly differentiated colorectal adenocarcinoma. On the basis of the microscopy results, the Por1 type is characterized by cancer cells with solid growth and little stroma; most cells contained round-shaped nuclei. The Por2 type is characterized by cancer cells with a predominantly trabecular structure; these tumors are rich in fibrous stroma. The two groups were compared for clinicopathological factors.
Results: The frequency of metastasis of the lymph node, liver, lung, and peritoneum in the Por2 group was significantly higher than that in the Por1 group. The survival rate in the Por2 group was lower than that in the Por1 group.
Conclusion: The classification system described in this study is a simple and easy method for predicting poorly differentiated colorectal adenocarcinomas, and the prognosis of patients with Por2 tended to be unfavorable than that of Por1.