Rathke's Cleft Cyst :MRI

This patient presented with hyperprolactinemia.  MRI reveals T1/T2 hyperintense lesion in the left posterior aspect of the pituitary with convex superior margin with minimal enhancement on post contrast scans.  The pituitary stalk is deviated to right.  Fluid level is noted in the axial section.  The optic chiasm & cavernous sinus appears normal. No parasellar abnormality. Differentials include first differential of rathke's cleft cyst versus other possibility of cystic adenoma. Rathke's cleft cysts are nonneoplastic, sellar or suprasellar epithelium-lined cysts arising from the embryologic remnants of Rathke's pouch in the pituitary gland. Hyperprolactinemia in Rathke cleft cyst is due infundibular stalk compression.