Abstract: Colorectal cancer is a rare pediatric tumor. Pediatric patients with colorectal cancer present with more aggressive tumor biology and at later stages of the disease, higher proportions of signet ring and mucinous histology, and less differentiation. The effective treatment is same as that received by adults. The overall prognosis of pediatric colorectal cancer is generally poor. Genetic mutations have been identified as the cause of inherited cancer risk in some colorectal cancers. Here, we presented a case of a pediatric patient carrying a maternally derived, heterozygous MYH  germline mutation (c.934– 2A>G,intron), the mutation was not reported in pediatric patients before. Also, the patient carried somatic mutations of proto-oncogene SMAD4  (R361C) and TP53 (Y234H). The patient underwent surgical resection, chemotherapy and targeted therapy, but the prognosis was not good. We also review the literature to summarize clinical features, gene mutations, management, and outcomes of pediatric colorectal cancer patient. Our results suggest that the genetic mutation of MYH  together with somatic mutations of proto-oncogene SMAD4  and TP53  may lead to the early onset colorectal cancer of the patient. Although the overall prognosis of pediatric colorectal cancer is generally poor, the pathogenesis may be related to hereditary genetic mutations as was found with the MYH  gene mutation in our case. Genetic screening can provide early diagnosis and improve prognosis.
Keywords: pediatric, colorectal cancer, heredity, MYH , gene mutations