Fourth ventricle primitive choroid plexus papilloma with divergent differentiation potentials: A case report

Choroid plexus tumors are rare tumors, although choroid plexus tumours account for 0.3%-0.6% of all brain tumors. We presented a rare case in four ventricle tumor, a primitive choroid plexus Papilloma with divergent differentiation potentials. In 43 year-old male, he started with postural vertigo, occipital cephalea, temporary diplopia and right lateropulsion from two years ago. MRI showed hyperintense tumor in the fourth ventricle with signs of cerebral edema and hemangioblastoma was proposed. Microscopically the tumor was composed of two histological components; one consists of blood vessels of different sizes and capillaries type a rich anastomosing network with these stromal cells are epithelioid-looking, broad with eosinophilic cytoplasm, and occasionally were vacuolated or foamy cytoplasm. The second one composed of epithelial cells forming papillae structures of varying sizes and shape with endothelial hyperplasia and some papillae presenting reached glomeruli-like structures, with ependymoma and haemangioblastoma appearance. The case presented may constitute a new neoplastic entity within the recently described spectrum of central nervous system tumors with ependymal features. Just two cases of this rare combination of different histological patterns have been reported in choroid with displacement and maldifferentiation of primitive, multipotent neuroepithelial cells.