Diagnostic imaging of focal nodular hyperplasia of the liver developing during nitrofurantoin therapy.

An asymptomatic palpable liver tumor developed in a six-year-old girl seven months after commencement of prophylactic nitrofurantoin therapy for recurrent urinary tract infections. The tumor was examined by 99mTc colloid radionuclide scan, compound ultrasonography and angiography. Ultrasonography demonstrated a large, solid tumor (5 x 5 x 8 cm) in the right lobe of the liver which had an echogenic central core surrounded by an area giving low-amplitude echoes. Angiography disclosed that the tumor was well demarcated and hypervascular, containing large tortuous arteries. The uptake of radionuclide in the tumor was normal. The tumor was resected and the pathological findings were typical for focal nodular hyperplasia (FNH) of the liver. The combination of the findings of these three diagnostic imaging methods is probably specific for uncomplicated FNH, a benign and innocuous tumor of the liver.