P4654 - Rising Concerns: A Case of YO-CRC in a 24-Year-Old Male

Susan Kais, MD, Matthew Soliman, , Addie Schumacher, MD, Madison Lange, ANPC
University of Cincinnati, Cincinnati, OH

Introduction:

Colorectal cancer (CRC) is the 3rd most commonly diagnosed cancer & the second leading cause of cancer-related deaths worldwide. CRC incidence has stabilized or declined in high-income countries due to screening in individuals aged 45 & older, there has been a concerning rise in younger populations, termed young-onset colorectal cancer (YO-CRC), which refers to cases diagnosed before age 50. By 2030, YO-CRC is projected to comprise 11% of colon cancer & 23% of rectal cancer diagnoses. This trend suggests a strong birth cohort effect, implicating environmental & lifestyle changes as key contributors. This case report highlights the importance of maintaining a high index of suspicion for CRC in younger patients.

Case Description/Methods:

We present a 24-year-old male with no significant PMH who presented to the ED with unintentional weight loss, abdominal pain, nausea, vomiting, constipation, & malaise over 3 months. CT revealed a large cecal mass with extensive mesenteric adenopathy. No family history of CRC. Lab studies showed iron-deficiency anemia & elevated CRP, while tumor markers were unremarkable. Colonoscopy found a partially obstructing cecal mass, & biopsy indicated moderately differentiated invasive adenocarcinoma. Immunostaining revealed loss of MLH1 & PMS2 proteins, suggestive of mismatch repair deficiency. Genetic analysis showed no mutations in NRAS or BRAF, indicating a diagnosis of Lynch Syndrome (LS).

Discussion:

LS, resulting from mutations in DNA mismatch repair genes, typically presents CRC at ages 44 to 61. Our patient’s diagnosis at age 24 is notably early. Absence of BRAF mutations & loss of MLH1 & PMS2 support this diagnosis. Emerging evidence suggests that environmental factors & dietary patterns may contribute to the rising incidence of YO-CRC, including high red meat consumption, low fiber intake, & early-life exposures. Disparities in incidence rates have also been observed among different ethnic groups. The increasing rates of YO-CRC have prompted guideline changes, recommending average-risk screening starting at age 45. However, many YO-CRC patients are diagnosed earlier, necessitating tailored even earlier screening strategies. Our case emphasizes the need for heightened clinical suspicion in young patients presenting with GI symptoms & highlights the importance of earlier diagnostic workup & further research into YO-CRC's molecular mechanisms for improved patient outcomes. As well as the rise of YO-CRC which may again support the need to start CRC earlier than 45.

Disclosures:


Susan Kais, MD, Matthew Soliman, , Addie Schumacher, MD, Madison Lange, ANPC. P4654 - Rising Concerns: A Case of YO-CRC in a 24-Year-Old Male, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.