Ependymoblastoma in an adult: a diagnostic challenge on cytology.

Ependymoblastoma is a rare, highly malignant brain tumour considered by most to be a subtype of primitive neuroectodermal tumour manifesting in young children. The authors present an unusual case of ependymoblastoma occurring in an 18-year-old female, one of the oldest patients reported with this tumour. The crush smears were highly cellular comprising singly scattered small, round immature cells with fine granular chromatin. The paraffin sections showed a tumour composed of uniform, small-sized, primitive cells forming well defined multi-layered rosettes with prominent mitoses. The tumour cells exhibited diffuse Vimentin and focal glial fibrillary acidic protein reactivity. A few cells showed S-100 reactivity. The patient underwent radiotherapy following complete tumour debulking but, succumbed to the disease within 2 months of diagnosis.