Focal nodular hyperplasia that mimicked a liver metastasis from a soft tissue sarcoma: a case report

BACKGROUND: Imaging modalities (computed tomography (CT), ultrasonography, and magnetic resonance imaging (MRI)) have only limited ability to distinguish liver focal nodular hyperplasia (FNH) from metastatic liver tumors. Here, we report a patient who underwent surgery for benign FNH that mimicked a liver metastasis from soft tissue sarcoma (STS). CASE PRESENTATION: A 23-year-old man with a history of several surgeries for metastatic abdominal STS, developed a hepatic tumor accompanying peritoneal STS recurrence. He was diagnosed with a metastatic liver tumor from the STS, based on imaging studies for the hepatic tumor that showed a growing hypervascular lesion and hypo-intensity in hepatic phase on dynamic CT and MRI. However, when the liver and peritoneal tumors were resected, histological diagnosis showed the hepatic tumor to be benign liver FNH. CONCLUSIONS: Although FNH should be considered as a differential diagnosis for hypervascular hepatic tumors, it has few typical findings, and its appropriate management is controversial. A lesion strongly suspected of being a metastatic liver tumor might require surgical resection.