Hello doctor my mother's age is 42 she has swelling in her left ear for about 4 years we taken CT scan result came she has soft tissue in parotid gland measuring 25�26 mm. And we taken biopsy before 2 years it came non cancerous my question is can it transform into cancerous? And some times she have swelling in left side of her neck after 2 or 1 days it goes invisible.