MRI mimics of primary empty sella: a retrospective educational case series highlighting clinical and uncommon magnetic resonance imaging presentations.

AIM: We aimed to describe a few rare differential diagnoses of primary empty sella by reporting clinical and magnetic resonance imaging (MRI) findings that can potentially mislead the diagnosis.

MATERIALS AND

METHODS

The study included patients with intrasellar arachnoid cyst, pituitary stalk interruption syndrome, spontaneous transsellar meningoceles extending to the sphenoid sinus, intrasellar Rathke cleft cyst, and pituitary adenoma with cystic degeneration.

RESULTS

Differentiation from primary empty sella was possible based on the pituitary morphology and location, pituitary stalk configuration, sellar floor integrity, extension to the sphenoid sinus, and MRI signal characteristics. Cerebrospinal fluid-equivalent signal intensity without enhancement was observed in the intrasellar arachnoid cyst. Pituitary stalk interruption syndrome was characterized by absent or interrupted stalk with an ectopic posterior pituitary. Spontaneous transsellar meningoceles extending to the sphenoid sinus demonstrated herniation of cerebrospinal fluid-containing meninges through sellar defects. Rathke's cleft cyst may simulate partial empty sella, however, the presence of a midline cyst and occasionally an intracystic nodule helps establish the diagnosis. Cystic degeneration in pituitary adenomas may mimic empty sella appearance, but asymmetric elevation of the diaphragma sellae, deviation of the pituitary stalk, and subtle peripheral enhancement of residual tumor tissue can provide important diagnostic clues.

CONCLUSION

A structured MRI evaluation focusing on pituitary anatomy, stalk configuration, sellar floor integrity, sphenoid sinus pathology, and subtle cystic lesions characteristics can reliably differentiate true primary empty sella from its rare mimics.