A 25-year-old man without a prior history of liver disease presented with an 18-cm tumor of the right hepatic lobe, which was associated with multiple nodular lesions in the remaining parenchyma. The histologic and immunohistochemical features of the neoplasm were those of a poorly differentiated leiomyosarcoma with epithelioid features. The nodular lesions measured up to 4 cm in greatest dimension and had gross and microscopic features of focal nodular hyperplasia. This case suggests that multiple focal nodular hyperplasia may occasionally represent a parenchymal reaction to abnormal blood supply developing within the liver as a consequence of an enlarging malignant tumor.