Presentation
Head injury. Incidental (?) finding.
Patient Data
A suprasellar and intrasellar CSF density cyst is present. Some supraclinoid carotid calcification is present. Otherwise, no calcification is seen in the region of interest.
A large lobulated cystic appearing mass is seen with both intra and suprasellar components. The suprasellar component compresses the prechiasmal right optic nerve and hypothalamus. The infundibulum is compressed and deviated to the right. The sella is remodeled. Pituitary tissue appears compressed on the floor and posteriorly in the sella. Thin linear septal enhancement is evident internally. No restricted diffusion, susceptibility artefact, intrinsic T1 hyperintensity or solid enhancement.
Conclusion:
A Rathke's cleft cyst, or possibly an arachnoid cyst, is favored. Less likely differential diagnoses include cystic macroadenoma and craniopharyngioma.
Case Discussion
The patient went on to have a resection.
Histology
The sections show cyst lining, which comprises a single layer of ciliated flattened to cuboidal epithelium. The epithelial cells show no nuclear atypia. The wall is fibrous. There is some adjacent normal anterior pituitary gland tissue. No evidence of pituitary adenoma or malignancy is seen.
FINAL DIAGNOSIS: Rathke cleft cyst.
Discussion
Although most Rathke's cleft cysts are small and intrapituitary, they can sometimes, like in this case, extend out of the fossa and into the suprasellar cistern.