Abdominal tumor masses are a very rare disease in the fetus. The authors present the first reported case of neonatal multicystic adenomatoid hamartoma of the pancreas associated with well-differentiated fetal epithelial subtype hepatoblastoma and reveal clinical, histologic, and imagistic aspects. Case presentation: A 36-week-old female newborn in whom a 25-week ultrasound showed a relatively homogeneous pancreatic echogenic mass (34 × 30 × 55 mm) with compression of the inferior vena cava and retrograde dilation. Postnatal CT showed a giant pancreatic tumor mass (113 × 70 × 60 mm), with areas enhancing contrast and cystic/necrotic areas and a hypodense, hypocaptive nodule of 8 × 6 mm located at segment IV of the liver; thrombosis of the subhepatic segment of the inferior vena cava and both renal veins. Histopathological and immunohistochemical studies confirmed the diagnosis of multicystic pancreatic adenomatoid hamartoma and well-differentiated fetal epithelial subtype hepatoblastoma. Conclusions: Pancreatic hamartoma can be difficult to diagnose (especially prenatal), with or without nonspecific symptoms. The synchronous presence of hepatoblastoma complicated the therapeutic conduct and prognosis of this case, with the diagnosis being confirmed histopathologically and immunohistochemically after liver biopsy.