Review ArticlesThe Diagnosis of Malignancy in Effusion Cytology: A Pattern Recognition ApproachPereira, Telma C. MD*; Saad, Reda S. MD, PhD* †; Liu, Yulin MD, PhD* †; Silverman, Jan F. MD* †Author Information *Department of Pathology and Laboratory Medicine, Allegheny General Hospital, Pittsburgh, PA †Drexel University College of Medicine Reprints: Telma C. Pereira, MD, Department of Pathology, Allegheny General Hospital, 320 E North Avenue, Pittsburgh, PA 15212 (e-mail: [email protected]) Received for publication April 13, 2006; accepted May 25, 2006 Advances in Anatomic Pathology: July 2006 - Volume 13 - Issue 4 - p 174-184 Buy Abstract This review presents a pattern recognition approach for the diagnosis of malignant effusions. The cytomorphologic features of reactive mesothelial proliferation, mesothelioma and metastatic carcinoma are presented. In addition, the role of ancillary studies in challenging cases and the importance of integrating clinical findings are stressed. An algorithmic approach to the workup of serous effusions as well as pitfalls for false-positive diagnosis are discussed. © 2006 Lippincott Williams & Wilkins, Inc.