Early colorectal cancer from “de novo” carcinogenesis with submucosal invasion: a case report and review of the literature

Background: Colorectal cancer (CRC) mostly develops through the traditional “adenoma-carcinoma sequence”, however there is a rare “de novo” carcinogenic pathway in which cancer originates from normal mucosa. Here, we report a case of early CRC caused by “de novo” carcinogenesis with submucosal invasion and conduct a literature review of this special type of CRC.Case presentation: A 66-year-old man underwent a screening colonoscopy that revealed a polyp-like lesion (type 0-IIa+IIc in the Paris classification) approximately 0.5 cm in diameter in the descending colon. The patient underwent endoscopic submucosal dissection (ESD); postoperatively, he was pathologically diagnosed with moderately differentiated adenocarcinoma without an adenomatous component from the “de novo” carcinogenic pathway, accompanied by submucosal invasion to a depth of 600 μm. There was no venous or lymphatic permeation, and the margins were negative. A year later, follow-up examinations did not reveal tumour recurrence.Conclusions: Early “de novo” cancer has a low incidence and a low discovery rate through endoscopy. In this case report, we provide informative details about the presentation of such cancers under endoscopy and further support for the aggressive malignant potential of early “de novo” cancer. The development of advanced CRC can be effectively prevented, and the prognosis of these patients can be improved with active early treatment.

Effect of Helicobacter Pylori Infection on Malignancy of Undifferentiated-type Gastric Cancer

Background: Although almost all cases of gastric cancer are caused by Helicobacter pylori (HP) infection, there are some rare exceptions. Furthermore, the clinicopathological characteristics of gastric cancer may differ depending on HP infection status. This study aimed to determine the clinicopathological characteristics of undifferentiated-type gastric cancer (UD-GC) according to HP status.Methods: The study involved 83 patients with UD-GC who were selected from 1559 patients with gastric cancer who underwent endoscopic resection at our hospital and whose HP infection status was confirmed. Clinicopathological characteristics were evaluated according to HP status (eradicated, n=28; infected, n=32; not infected, n=23).Results: In patients without HP infection, UD-GCs were <20 mm and intramucosal with no vascular invasion. In patients with eradicated HP, there was no correlation between development of UD-GC and time since eradication. Furthermore, 75% of patients with a tumor detected ≥5 years after eradication had undergone yearly endoscopy. Submucosal or deeper invasion was observed in 50% of patients and vascular invasion in 75% of patients whose UD-GC was detected ≥10 years after eradication. The proportion of patients with UD-GC and submucosal or deeper invasion was zero in the group without HP infection, 14.3% in the group with eradicated HP, and 10.5% in the HP-infected group.Conclusion: The clinicopathological characteristics of UD-GC were similar between HP-infected patients and HP-eradicated patients. Patients with eradicated HP whose UD-GC developed long after eradication had high rates of vascular and submucosal invasion. In contrast, UD-GC was curable by endoscopic resection in all patients without HP infection.