Undifferentiated Embryonal Sarcoma of Liver- A Rare Case Entity

Abstract

Undifferentiated Embryonal Sarcoma of the Liver (UESL) is a rare hepatic malignant mesenchymal neoplasm in the paediatric population, typically affecting children between 6-10 years of age without sex predilection. It accounts for 9-15% of paediatric liver malignancies, with an incidence of 0.6-1.2 cases per one million patients. Here, the authors present a case of an 11-year-old male, who presented with right upper quadrant pain, loss of appetite for the past one month, and high-grade fever for the past three days. On examination, a firm mass in the right hypochondrium and epigastrium, about 4 cm below the right costal margin, was noted, moving with respiration. Blood work showed normal values and normal alpha-fetoprotein levels. An ultrasonogram revealed a cystic lesion, while a contrast-enhanced Computed Tomography (CT) scan showed a large hepatic space-occupying lesion with cystic and solid architecture, with the following differential diagnosis as, embryonal sarcoma and hepatoblastoma. The patient underwent surgery for a hepatic hydatid cyst, and the procedure performed was percutaneous aspiration, irrigation and respiration. Gross examination revealed multiple grey-brown and grey-white fragments with a variegated appearance. Microscopic analysis showed a malignant neoplasm composed of spindle cells, stellate cells, multinucleated giant cells in a myxoid stroma, with many atypical mitoses present. Periodic Acid-Schiff (PAS) positive eosinophilic hyaline globules were observed in the tumour cell cytoplasm, along with extensive areas of haemorrhage and necrosis. The final diagnosis of embryonal sarcoma was made after a panel of Immunohistochemistry (IHC) markers. The present case is presented here due to its rarity and diagnostic challenge, arising from the lack of a characteristic clinical presentation, serological markers and inconclusive radiological findings.