Xanthogranulomas of the choroid plexus are common benign lesions which only rarely cause symptoms. These consist of desquamated epithelium into the lumen of choroid cysts within the choroid plexus. Therefore the MRI signal characteristics depend on the mixture of lipid, fluid and blood products. They appear like cystic lesions. A helpful distinctive feature is high signal on DWI. ADC may be intermediate or low signal. The sizes vary ranging from tiny lesions to large prominent masses. In this patient the largest lesion is 1.5x1cm which is seen in left posterior horn, They can also present in the trigone of the lateral ventricle. These lesions are bilateral in 2/3 of patients as seen in this patient.

These are almost certainly incidental findings as the patient's clinical presentation cannot be explained by this lesion.

Symptomatic cases are rare and commonly due to lesions located in the third ventricle causing obstruction of the Foramen of Monro.

The main differential diagnosis for Xanthogranuloma is Choroid plexus cyst

Submitted by  Dr. Aruna Pallewatte, Dr. Lakmini Alahakoon and Dr. Priyanka Gunathunga.