Primitive neuroectodermal tumor of the liver: a case report.

Ewing sarcoma/primitive neuroectodermal tumor is a rare tumor of soft tissues of thoraco-pulmonary regions, pelvis and lower extremities. Involvement of visceral organs by primitive neuroectodermal tumor is even rarer, with the kidney being the most commonly involved organ. Involvement of the liver has been reported in the form of metastasis from other primary sources presenting as liver abscess. We report a 20-year-old lady presenting with massive hepatomegaly, with computed tomography scan evidence of diffuse hepatomegaly and a normal porta and intrahepatic biliary radicles. She subsequently underwent ultrasonography-guided true-cut needle biopsy of the liver. Histopathology of the liver revealed nests of small round blue tumor cells in the background of hepatocytes infiltrating the liver, which expressed Mic-2 and Fli-1, and were negative for cytokeratin, desmin, hepatocyte-specific antigen (OCHIE5), synaptophysin, chromogranin A and CD-20. Immunohistochemistry revealed CD-99-positive. Extensive search regarding any possible different site of involvement by the tumor was negative. The patient responded to a combination therapy of vincristine, adriamycin and cyclophosphamide alternating with ifosfamide and etoposide 3 weekly over 43 weeks and has been doing well even after 1 year of diagnosis. The clinical presentation, the macroscopic aspect, together with the histological pattern, the cytological characteristic and the cellular immunophenotype lead to the diagnosis of primary primitive neuroectodermal tumor of the liver which responded well to combination chemotherapy.