Development of Focal Nodular Hyperplasia after Cyclophosphamide-Based Chemotherapy in a Patient with Breast Cancer

Focal nodular hyperplasia (FNH) is the second most common liver cell-derived benign tumor. It is postulated that chemotherapy-induced hepatic circulatory abnormalities, like sinusoidal obstruction syndrome (SOS), could lead to the development of FNH. Cyclophosphamide was also reported to induce SOS in a synergistic effect with total body irradiation. However, none of cyclophosphamide-related FNH had ever been reported before. In this case report, we present a female patient who was treated with neoadjuvant chemotherapy of cyclophosphamide (500mg/m²)-docetaxel (75mg/m²)-pharmorubicin (90mg/m²) regimen every 3 weeks for breast cancer developed FNH after 4 courses of treatment. The patient had no chronic liver disease, no history of smoking, drinking, or medication use. The chronological correlation between the chemotherapy and the appearance of the FNH suggested a cause-effect association. Therefore, this is the first case report about development of FNH after cyclophosphamide-based chemotherapy. Taking into account the frequency of breast cancer, it is instructive to recognize such observation of FNH in the context to make the differential diagnosis with hepatic metastasis.