The frequency and cancer risk associated with the atypical cytologic diagnostic category in endoscopic ultrasound-guided fine-needle aspiration specimens of solid pancreatic lesions: a meta-analysis and argument for a Bethesda System for Reporting Cytopathology of the Pancreas - Abdelgawwad, M S; Alston, E; Eltoum, I A (Cancer Cytopathol, 2013)