The Diagnosis of Malignancy in Effusion Cytology: A Pattern Recognition Approach

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.

Guidelines for Pathologic Diagnosis of Malignant Mesothelioma: 2012 Update of the Consensus Statement from the International Mesothelioma Interest Group

“…This includes enlargement of cytoplasm, nucleus, and nucleolus. 22 The presence of macronucleoli. However, prominent nucleoli can be present in reactive mesothelial cells and not all MM cells have macronucleoli.…”

False‐positive interpretations in respiratory cytopathology: Exemplary cases and literature review

“…In a recent report by Pereira et al, the authors mentioned that reactive mesothelial proliferations tend to produce cell clusters which are small, consisting of only a few cells. 32 That finding is in contrast to the large clusters that are expected in both mesothelioma and metastatic adenocarcinoma. Furthermore, cytoplasmic vacuoles in reactive mesothelia contrast with those of many adenocarcinomas, because mesothelial vacuoles tend to be paranuclear, small, and indistinct, without indentation of the nuclear membrane.…”

“…Furthermore, cytoplasmic vacuoles in reactive mesothelia contrast with those of many adenocarcinomas, because mesothelial vacuoles tend to be paranuclear, small, and indistinct, without indentation of the nuclear membrane. 32 Distinguishing reactive mesothelial cells from those of mesothelioma or adenocarcinoma is often challenging. In this setting, the routine use of immunohistochemistry has been advocated by many authors.…”

Automated Quantification of DNA Aneuploidy by Image Cytometry as an Adjunct for the Cytologic Diagnosis of Malignant Effusion

“…For many years, cytologic examination of effusion cell either by conventional cytology smear or by monolayer preparation has been the principal method for diagnosis of malignant effusion [21]. However, the ability of visual detection of cancer cells in effusion samples is heavily dependent on the diagnostic skill and experience of cytopathologists.…”