The incidence of colorectal cancer (CRC) is increasing year by year, and early diagnosis is of great significance to improve the prognosis of patients. Circulating cell-free nucleic acid (cfNA) has the advantages of non-invasive, real-time monitoring, and overcoming tumor heterogeneity. The characteristics of cfNA content, mutation, methylation and fragmentation patterns provid important reference value for early diagnosis, curative effect monitoring, prognosis judgment and medication guidance of CRC. However, the practical application of cfNA in the clinical diagnosis and treatment of CRC still needs to solve the problems of unstandardized detection technology, high detection cost, screening of markers with high diagnostic efficacy, and construction of multi-combination models. These challenges will provide new directions for future cfNA research.

Objective:To explore the clinical characteristics, diagnosis, treatment and prognosis of inverted Meckel′s diverticulum in children, and to summarize the clinical experience.Methods:Ten children who received surgical treatment in Beijing Children′s Hospital, Capital Medical University from October 2018 to October 2021 were retrospectively analyzed.The children were diagnosed with Mecker′s diverticulum.Their data were complete and their fo-llow-up information was available.The clinical features, diagnosis, treatment and prognosis were summarized.There were 6 males and 4 females, whose age of onset ranged from 5 months to 12 years and 5 months.The clinical manifestations were abdominal pain in 8 cases, crying in 2 cases and bloody stool in 3 cases.B-ultrasound showed suspected diseases secondary to inverted Meckel′s diverticulum, including small intestinal intussusception in 6 cases and back junction type intussusception in 4 cases.One case of small intestinal intussusception was misdiagnosed after laparoscopic exploration in other hospitals and suffered from recurrent intussusception.All patients underwent segmental bowel resection.Results:Of the 10 children, 8 cases received laparoscopic exploration and 2 cases underwent open surgery for secondary intestinal necrosis.Postoperative pathology revealed Meckel′s diverticulum.Ectopic tissue was accessible in 8 cases, including ectopic gastric tissue in 7 cases, and ectopic pancreas in 1 case.During the postoperative follow-up period (1 month-3 years), the patients were generally in good condition with no complications such as intestinal obstruction.Conclusions:Intussusception secondary to inverted Meckel′s diverticulum is rare and difficult to diagnose before operation.The diagnosis should be confirmed by surgical exploration and postoperative pathology.However, careful surgical exploration is required since inverted Meckel′s diverticulum is prone to be misdiagnosed during exploration.