Contribution of Nuclear Morphometry by Confocal Laser Scanning Microscopy to the Diagnosis of Malignant Bile Duct Strictures

To determine the clinical utility of nuclear morphometry by confocal laser scanning microscopy for the diagnosis of malignant biliary strictures. The study included 51 patients with bile duct strictures who underwent endoscopic retrograde cholangiopancreatography (ERCP). Based on the initial workup, 6 patients were diagnosed with benign strictures, and 12 patients had malignant strictures, while in the remaining 33 cases the diagnoses were inconsistent, due mainly to inadequate samples. Smears from ERCP brushings were stained for DNA with propidium iodide. Nuclear morphometry was assessed on images acquired by a confocal laser scanning microscope. Three parameters-nuclear volume, nuclear shape and nuclear staining intensity-were calculated. Based on these features, a distinctive nuclear morphometric pattern was attributed to the malignant nuclei, and its predictive value was assessed prospectively in the 33 undiagnosed cases. After an overall median follow-up period of 8 months, 19 patients were diagnosed with malignant strictures, and 14 patients were considered to have benign strictures. With respect to the prediction of malignancy, the sensitivity of the described method was 78%, the specificity was 63%, the positive predictive value was 64%, and the negative predictive value was 80%. Nuclear morphometry may provide significant information for the diagnosis of malignant bile duct strictures when conventional cytology fails to.