P11.39.B An unusual case of astroblastoma in adult: a case report and review of the literature

Abstract

Background Astroblastoma is an uncommon glial neoplasm of controversial histogenesis, clinical behavior and response to treatment yet to be understood. It usually appears in the cerebral hemisphere of young patients, preferably in the frontal and parietal lobes. Histologically, its characteristics overlap with high-grade gliomas, making the differential diagnosis between these entities complex. Clinical, radiological, histopathological correlations and, if necessary, genetic tests (MN1 Rearrangement) are essential for an accurate diagnosis. Material and Methods We present a case report based on data collected retrospectively from electronic medical records. Results A 63-year-old male with a 3-month history of headache and one episode of mental confusion. In the neurological exam, language alteration was noted and the other systemic exams were normal. Magnetic resonance imaging of the brain revealed an intra-axial expansive formation involving the insula, superior and middle temporal gyrus, left portion of brainstem, with lobulated contours and heterogeneous, solid-cystic appearance with intermingled hematic foci. The solid portion had heterogeneous contrast enhancement and foci of gross calcification. The lesion was resected and the postoperative MRI showed no residual tumor lesion. Histopathological evaluation showed an extensive pattern of perivascular pseudorosettes of astrocytic cells with broad processes radiating to central vessels, in addition to frequent foci of hyalinization. Immunohistochemistry showed positive staining with antibodies to glial fibrillary acidic protein (GFAP), vimentin and S100 protein, in addition to membranous positivity for epithelial membrane antigen (EMA). The Ki-67 index was 20%. Based on these data, the diagnosis of NOS astroblastoma was established. Four months after resection, imaging follow-up displayed enhancement of the surgical cavity, suggestive of local recurrence. The patient underwent three-dimensional conformal radiotherapy with a total dose of 6000cGy in 30 sessions, followed by adjuvant chemotherapy with temozolomide.The patient did not have tumor recurrence until the last follow-up made 16 months after surgery. Conclusion This is an atypical case of an extremely rare glial tumor of the central nervous system, since most patients with astroblastoma range from 3 months to 40 years (median: 15 years), which makes the diagnosis challenging.