Medulloblastoma (MB) is the most common malignant pediatric brain tumor and is currently treated with combined therapies. Recent advances in genetics and protein expression in this entity have led to the elaboration of a new molecular classification, and novel targeted therapies are currently under trial. This objective of this study was to describe the cytomorphologic features of MB in cerebrospinal fluid (CSF).
The authors conducted a retrospective study of 194 CSF samples from 70 pediatric patients who had a history of primary MB. The samples consisted of CSF cytospins that were stained according to the May-Grunwald Giemsa and/or Papanicolaou methods.
In 32 patients, it was possible to establish a confident diagnosis of metastatic MB. Common morphologic features included cell clustering, nuclear irregularity, molding and enlargement, and prominent nucleoli. Multinucleation as well as mitotic and apoptotic figures were less frequently observed. Fifteen samples that presented neither cell clustering nor nuclear molding were classified as suspicious.
Cell clustering with nuclear molding is a key feature for the diagnosis of leptomeningeal metastasis of MB. Cancer (Cancer Cytopathol) 2015;123:644-649. © 2015 American Cancer Society.