Schwannoma : Antoni A & B
Schwannomas are composed of cellular Antoni A areas alternating with hypocellular Antoni B areas. Antoni A areas are composed of interlacing bundles of spindle cells (Schwann cells) with wavy or oval nuclei, eosinophilic cytoplasm, and indistinct cytoplasmic borders. Intranuclear vacuoles may be present. Antoni B areas are hypocellular and less compact than Antoni A areas. They consist of haphazardly arranged spindle cells in a loose myxoid or hyalinized stroma containing a few inflammatory cells and delicate collagen fibers. Antoni B areas also contain variably-sized, ectatic deformed blood vessels which frequently have hyalinized walls and contain thrombi.