Biliary rhabdomyoscarcoma mimicking choledochal cyst

A 3-year old male presented with complaints of pruritus, abdominal pain for 3 weeks and jaundice. Stools were acholic. There was jaundice, liver palpable 3 cm below right costal margin, no ascites or palpable masses. Serology revealed albumin 2.9 g/dl; ammonia of 31 mmol/l; elevated conjugated bilirubin, GGT, ALT, AST and alkaline phosphatase; alpha fetoprotein 1.3 ngm/ml; BhCG 9.1 IU/; PT 12.3 secs, INR 0.9; negative hepatitis A,B,C serology. CT scan showed a non-calcified heterogeneously enhancing mass centered at the liver hilum. MRCP showed a large heterogeneously enhancing, partially solid mass in the region of the porta hepatic. Liver biopsy revealed patternless proliferation of polymorphic oval to spindled shaped neoplastic cells. There was bile ducts distortion. Immunohistochemistry revealed positivity for vimentin, desmin.These findings were diagnostic for biliary rhabdomyosarcoma.There was no evidence of metastasis. Chemotherapy was initiated. Repeat imaging 6 months after initiation of treatment showed improvement in the degree of intrahepatic ductal dilatation and decrease in tumor bulk size. Rhabdomyosarcoma is the most common malignant tumor of the biliary tree in childhood. It is difficult to diagnose and delayed diagnosis influences the prognosis.