Benign neck masses showing restricted diffusion: Is there a histological basis for discordant behavior?

Figure 6 Sinonasal hemangiopericytoma in a 45-year-old lady. A: Coronal T2W image shows mildly expansile sinonasal mass involving, extending to bilateral ethmoid sinuses. Small intracranial extension noted in anterior cranial fossa (dashed arrow); Retained secretions in right maxillary sinus (solid arrow); B: ADC map shows restricted diffusion in the mass; C: Photomicrograph shows spindle cells with mild pleomorphism (H-E; original magnification: × 100). ADC: Apparent diffusion coefficient.