Cytology plays a pivotal role in the diagnosis of pleural effusions. In many cases, immunocytochemistry (ICC) is required to elucidate the etiology of the atypical cells. Effusions are samples that present unique problems for ICC. To date there is no standardization of ICC methods for effusions and cytology in general.
The authors review the most commonly used cytologic preparations, fixatives, and antibodies used in effusion ICC.
Through the utilization of cell block preparations and a panel of antibodies appropriate for the differential diagnosis in question, ICC conditions utilized in surgical pathology can be most closely replicated.
ICC may provide reliable insights into various diagnostic dilemmas in effusion cytology, provided that laboratory standardization practices are followed.