Collision Lesions

The concomitant presence of two or more intrasellar lesions is far from infrequent and may complicate the diagnosis: Pituitary adenoma, Rathke cleft cyst, meningioma, aneurysm can coexist. Association of PitNET and RCC are the less rare. In this case, the characteristic midline location of RCC is not recognized, the cyst being pushed away by the adenoma. This is another situation where the axial T1W sequence is helpful in showing the strict contact between RCC and posterior lobe. It is also noticeable that the PitNET imprints on the RCC and not the reverse. Another difficult diagnosis refers to the concomitant presence of a pituitary macroadenoma and a cavernous sinus meningioma.