Focal nodular hyperplasia of the liver: Diagnostic role of smear cytology vs microhistology following ultrasound-guided fine needle biopsy

With computed tomography (CT) and ultrasonography (US) the diagnosis of asymptomatic focal nodular hyperplasia (FNH) of the liver has become more frequent. As this condition has a benign course with no risk of bleeding it should be managed conservatively. Unfortunately the CT or US diagnosis, even when supported by other imaging techniques, is not always certain and so many of these patients undergo unnecessary surgery. We examined 22 patients with FNH, by means of fine needle biopsy (FNB) under US control to compare smear cytology and microhistology for diagnostic accuracy. FNB with microhistology supplied the correct diagnosis in 94.7% of cases versus 64.2% for smear cytology. Given the safety, low cost, and practicality of FNB for outpatients, along with the accuracy of microhistology, we recommend this approach for the diagnosis of FNH.