Primary Hepatic Yolk Sac Tumor: A Case Report of a Ruptured Tumor in a 22-month-old Boy

Primary hepatic yolk sac tumor is a rare extra-gonadal germ cell tumor in children and adults. Two important differential diagnoses for hepatic tumor in a pediatric patient are hepatocellular carcinoma and hepatoblastoma. A 22-month-old boy presented to our hospital with acute respiratory distress and increased serum alphafetoprotein. His symptom was caused by a ruptured massive intraabdominal tumor into the pleural space, which was identified during radiological workup. Surgical resection was performed and histological examination revealed the typical endodermal sinus pattern with additional solid, microcystic, polyvesicular, and hepatoid patterns. Absence of similar lesion in the gonads and other sites established the diagnosis of primary yolk sac tumor of the liver. The patient responded well to the adjuvant chemotherapy, which consisted of cisplatin, etoposide, and bleomycin. Our case illustrates the diagnostic challenge of an extremely rare primary hepatic yolk sac tumor and the improved survival rate with multimodal therapy. Considering this rare entity as a differential diagnosis of liver tumors in children is important for timely diagnosis, appropriate management, and accurate prognostication.