Rhabdomyosarcoma Rhabdomyosarcoma can occur anywhere in the abdomen or pelvis where there is striated muscle Tumors are particularly common in the pelvis, involving the prostate, uterus or vagina, and retroperitoneal structures, but they have also been found in the common bile duct and other unusual sites These tumors can reach a large size before they become symptomatic, and each must be managed individually, depending on the site of origin, extent of growth, and the degree of spread Hepatomas The most common primary GI tract neoplasm is hepatic in origin Hepatoblastoma and hepatocellular carcinoma are the two main subgroups of liver tumors; they are clinically indistinguishable at presentation Many are asymptomatic, but symptoms such as early satiety, weight loss, and abdominal pain may be seen, especially with very large tumors More often, the tumor is discovered after caregivers notice a change in the appearance of the abdomen They are usually seen in older infants and young children Increased levels of alpha-fetoprotein are associated with both types Differential diagnosis should include hemangioendothelioma, hamartoma, and renal and adrenal tumors These tumors are often initially diagnosed with US Further radiologic imaging is directed at diagnosis and the resectability of the tumor CT or MRI with angiography is often required to determine surgical approach ( Fig 116.25 ) Long-term survival is poor unless complete resection is possible Liver tumors commonly metastasize to the lungs, brain, and regional nodes