The right sided atlanto-occiptal assimilation is well seen again.
There is downward herniation of the cerebellar tonsils over a length of 11.5 mm from the foramen magnum level, in keeping with Chiari type I malformation. No syringomyelia/hydrocephalus.
There is a moderate sized well defined, thin walled cystic lesion noted in the right cerebello-pontine angle. This lesion follows CSF signal on all sequences. Mass effect noted in the form of compression of adjacent cerebellar hemisphere. No internal solid components. No restriction on ADC/DWI images. Features suggestive of arachnoid cyst. No features of bone remodelling.
Special thanks: Dr. Anand H.K