Cytological features in pilomyxoid astrocytoma: A case report with summary of prior published cases.

Pilomyxoid astrocytoma is a subtype of pilocytic astrocytoma that is described as a grade 1 tumour in the 2022 WHO classification of central nervous system tumours. It occurs predominantly in the hypothalamic region in infants. Although the histological features of pilomyxoid astrocytomas are well documented, few reports are available in the literature regarding cytological findings. Here we describe the squash cytological features of a case of pilomyxoid astrocytoma along with a summary of prior published cases. Smears for this type of tumour tend to be more cellular, with piloid cells arranged in an angiocentric pattern without Rosenthal fibres or eosinophilic granular bodies. A blue myxoid substance may be present in the background.