[Low grade astroblastoma: pathological and magnetic resonance findings]. / Astroblastoma de baixo grau: Achados patológicos e da ressonância magnética.

INTRODUCTION: The astroblastoma is an uncommon type of glial tumour. It accounts for less than 1% of all tumours of the central nervous system. It originates in the tanicytes, ependymal cells present in the embryo and usually seen in adolescents and young adults. Radiologically it presents as a well delimited, heterogeneous tumour with a solid component which takes up contrast and is cystic, giving the same signal as cerebrospinal fluid (CSF). The pathological characteristics are of the formation of radial astroblastic pseudorosettes with perivascular hyalinization. CASE REPORT: An 18 year old woman presented with a 15 month history of motor deficit of her right limbs with occasional left frontal headache and horizontal diplopia on looking towards the left. On examination there was minimal claudication of the right limbs and bilateral papilloedema. Magnetic resonance showed a very well circumscribed left prefrontal neoplasm of heterogeneous aspect, with areas of solid and cystic appearance in the different sequences. The area of cystic appearance did not show the CSF signal in all sequences of the pulse. The tumour was totally excised. On histological study there were radial astroblastic pseudorosettes with perivascular hyalinization, with two mitoses per 10 fields of great magnification and the final diagnosis was of low grade astroblastoma. The apparently cystic portion was composed of friable gelatinous tissue. Fifteen months after her operation the patient is still asymptomatic. CONCLUSION: We report the radiological and pathological findings of a low grade astroblastoma.