Primary hepatic gastrointestinal stromal tumor showing remarkable myxoid change and hemangiopericytoma-like pattern

Gastrointestinal stromal tumors (GISTs) in the liver are exceedingly rare. We report a case of hepatic GIST with myxoid changes and hemangiopericytoma-like patterns. A 69-year-old woman presented with epigastric discomfort, and underwent laparotomy for an extruded tumor in the liver. Five years later, recurrent tumor was excised. The primary tumor contained extensive necrotic and myxoid areas. Spindle and epithelioid cells plus a few giant cells with abundant myxoid matrix surrounded the necrotic areas. Immunohistochemically, the spindle cells were distinctly positive for KIT as well as vimentin and smooth muscle actin, leading to a diagnosis of hepatic GIST. The second excised tumor showed increased cellularity and nuclear atypia of epithelioid cells with hemangiopericytoma-like patterns. Although rare, we should consider GIST as a differential diagnosis for a hepatic mesenchymal tumor.