[Advanced colorectal cancer in a 19-year-old male patient with Lynch syndrome:a case report].

A 19-year-old male patient with abdominal pain and diarrhea was presented to our hospital. He was diagnosed with advanced colorectal cancer based on imaging. Lynch syndrome was suspected, considering his family history. After a laparoscopic subtotal colectomy, genetic testing confirmed a pathogenic variant in the MLH1 gene, leading to a definitive diagnosis of Lynch syndrome. The onset of colorectal cancer is extremely rare in the teenage years. Herein, we discuss the potential involvement of genetic anticipation, emphasize the importance of early surveillance in individuals at risk, and consider the use of multidisciplinary collaboration in providing comprehensive physical and psychological support.