A 46-year-old female patient with a large slow-growing craniocervical junction tumor is presented. Her complaints began 6 months before with sensory and painful sensations, sphincter impairment, and motor events (spastic tetraparesis, more pronounced on the left extremities). Magnetic resonance of the head revealed a rounded tumor of 2.5 cm in diameter, by its characteristics corresponding to meningioma, at the level of C1 vertebra and craniocervical junction, with the base at spinal canal anterior wall, occupying most of the craniocervical junction, compressing spinal cord and medulla oblongata. Intracerebral computed tomography angiography showed spared lumen and a satisfactory image of vertebral arteries bypassing the expansive growth at the occipital foramen, confirming slow tumor growth. Antiedematous therapy led to transient improvement in extremity strength and partial recovery of neurologic deficit, which resolved completely upon neurosurgical operation and rehabilitation. This case report exemplifies brain adaptability to slowly growing expansive neoplasms, based on its volume reduction up to the moment when further adaptation is not possible anymore, i.e. breaking of the mechanism of adaptation. Because of brain adaptability, such slowly growing tumors may stay asymptomatic for a long time. Brain plasticity also includes adaptation and autoregulation of the circulation, thus ensuring stable blood flow.