What two broad groups of tumours should be thought of in the differential diagnosis?
Broadly the differential consists of tumours specific to the pineal gland, or other tumours which can also occur in this region.
Does the fact that the mass is hyperdense and vividly enhancing help?
A little. One would have to suspect a highly cellular or dense tumour. Possibilities would therefore include a pineoblastoma, germ cell tumours, meningioma, lymphoma and high grade glioma.
A large well circumscribed mass is located in the pineal region. It is slightly hyperdense on precontrast imaging and demonstrates vivid contrast enhancement. It severely distorts the midbrain, compressing the aqueduct with marked obstructive hydrocephalus. A focus of increased density, probably calcium is seen immediately below the mass, possibly representing displaced pineal calcifications.