Clinicopathological features of cerebral lipoastrocytoma

Abstract

Objective To explore the clinicopathological features, immune phenotype, diagnosis and differential diagnosis, treatment and prognosis of cerebral lipoastrocytoma. Methods Retrospective analysis of the clinical manifestations, histopathological and immunohistochemical features were conducted in one case of cerebral lipoastrocytoma. Results A 48-year-old male presented with numbness and inflexibility of the fourth and little fingers of his left hand over the previous 2 weeks. Cranial MRI revealed a space-occupying lesion with cystic degeneration in the right parietal lobe that showed obvious enhancement after contrast administration. The patient subsequently underwent craniotomy with stereotactic gross total excision of the lesion. Adjuvant chemotherapy and radiation therapy were not administered. Histologically the tumor showed classical features of low-grade astrocytoma, including a few scattered medium-large neuron-like cells with prominent nucleoli and abundant cytoplasm. Most notably, the glial cells contained fat droplets or vacuoles giving an appearance of mature adipocytes. Focally microcystic change was evident resulting from adipocyte-like cells fusion with each other. Immunohistochemically, the tumor cells were reactive for glial fibrillary acidic protein (GFAP) and S-100 protein (S-100), focally positive for WT-1, weakly positive for oligodendrocytes transcription factor-2 (Olig-2), and negative for isocitrate dehydrogenase 1 (IDH1). Meanwhile, the tumor cells also expressed several neuronal markers including synaptophysin (Syn), microtube-associated protein-2 (MAP-2), neurofilament (NF), neuron specific enolase (NSE) and CD34. P53 protein was weakly expressed in 5% of tumor cells. Ki-67 labeling index was low (1% ). The patient remained well without recurrence 20 months after surgery. Conclusions Cerebral lipoastrocytoma is an extremely rare tumor. Histologically, the tumor showed classical features of low-grade astrocytoma and extensive lipomatous differentiation. Interestingly, the present case also showed neuronal differentiation confirmed by positive staining with neuronal markers. Diagnosis needs to be combined with pathological morphology and immune phenotype, which can distinguish from other neuroepithelial tumors with fat cell differentiation or xanthomatous change. doi：10.3969/j.issn.1672-6731.2014.01.009