Intraoperative consultation on pediatric central nervous system tumors by squash cytology.

Squash cytology (SC) is a very useful procedure during neurosurgical intraoperative consultation (IOC), and it is especially recommended for the evaluation of soft tumors or tumors that are highly cellular (just the characteristics of pediatric central nervous system [CNS] tumors). The aim of this review is to familiarize pathologists with the range of cytomorphologic appearances that can occur during IOC for pediatric CNS tumors and with the diagnostic dilemmas and pitfalls encountered in this setting. This article is based on the medical literature and the authors' experience with a large series of cases accrued over a 12-year period at 3 institutions. SC is a specially recommended procedure in IOC for pediatric CNS tumors; it reveals the fine cellular details and background features in a manner not seen in corresponding frozen sections. Indeed, a differential diagnosis between histologically look-alike processes can be achieved with more confidence if SC is employed.