Suprasellar Cystic Mass

Suprasellar Cystic Mass

Anne G. Osborn, MD, FACR



  • Enlarged Third Ventricle

    • Obstructive Hydrocephalus

    • Aqueductal Stenosis

  • Arachnoid Cyst

  • Craniopharyngioma

  • Neurocysticercosis (NCC)

Less Common

  • Rathke Cleft Cyst

  • Dermoid Cyst

  • Epidermoid Cyst

  • Enlarged Perivascular Spaces (PVSs)

Rare but Important

  • Pituitary Macroadenoma

  • Pituitary Apoplexy

  • Astrocytoma

    • Pilocytic Astrocytoma

    • Pilomyxoid Astrocytoma

  • Ependymal Cyst

  • Saccular Aneurysm


Key Differential Diagnosis Issues

  • Where does the mass originate?

    • Third ventricle: Think hydrocephalus > intraventricular cystic mass (ependymal cyst, craniopharyngioma)

    • Suprasellar cistern: Arachnoid, other congenital/infectious cysts

    • Pituitary gland/sella turcica: Necrotic/cystic neoplasm

    • Brain parenchyma: Enlarged perivascular spaces, cystic/low density neoplasm

Helpful Clues for Common Diagnoses

  • Enlarged Third Ventricle

    • CSF density/signal intensity

    • No enhancement (unless infection, neoplasm)

    • Obstructive Hydrocephalus

      • Can be intra- or extra-ventricular (noncommunicating or communicating)

      • If acute, periventricular “halo” of transependymal CSF

      • “Cystic mass” = dilated 3rd ventricle

    • Aqueductal Stenosis

      • ↑ Lateral, 3rd ventricles

      • Normal 4th ventricle

      • Usually longstanding, “compensated” so no transependymal CSF

  • Arachnoid Cyst

    • 10% of ACs suprasellar (SSAC)

    • Sharply marginated CSF density/signal intensity mass

      • Suppresses on FLAIR

      • Does not restrict on DWI

    • 3rd ventricle elevated, displaced over AC

      • Displaces temporal lobes laterally

      • Displaces midbrain, pons posteriorly

      • Infundibular stalk typically displaced anteriorly

      • “Mickey mouse ears” on coronal = cyst + lateral ventricles

    • If large, may also cause obstructive hydrocephalus

  • Craniopharyngioma

    • 90% of childhood craniopharyngiomas cystic

      • Cyst fluid hyperdense/intense to CSF

    • 90% have some Ca++ (globular or rim)

    • 90% enhance (rim, nodular)

    • Suprasellar cistern > > within 3rd ventricle

  • Neurocysticercosis (NCC)

    • Look for “clusters” of cysts in subarachnoid cisterns (“racemose” NCC)

    • Look for cyst + scolex

    • FLAIR best sequence to detect (cyst fluid doesn’t suppress completely)

Helpful Clues for Less Common Diagnoses

  • Rathke Cleft Cyst

    • 60% purely suprasellar or intrasellar with suprasellar extension

    • Variable density/signal intensity

      • Usually compared to CSF

      • 10% calcify (curvilinear, in cyst wall)

    • Look for

      • Intracystic nodule (45%)

      • “Claw” of compressed, enhancing pituitary displaced around cyst

  • Dermoid Cyst

    • Most common site = sellar/parasellar, frontonasal

    • Fat density/signal intensity

    • 20% have capsular Ca++

    • Look for evidence of rupture

      • Fat droplets in subarachnoid spaces

      • Fat-fluid levels in ventricles

      • Chemical shift artifact in frequency encoding direction

  • Epidermoid Cyst

    • Rare in suprasellar cistern

    • Lobulated, insinuating growth pattern

    • > 95% hypodense (similar to CSF)

      • FLAIR, DWI best to distinguish epidermoid from AC, enlarged 3rd ventricle

      • Epidermoid doesn’t suppress completely, restricts on DWI

  • Enlarged Perivascular Spaces (PVSs)

    • Usually variable-sized “clusters”

    • Off-midline (basal ganglia)

    • Round or ovoid (basal ganglia), linear (white matter)

    • Like CSF on all sequences (contain interstitial fluid)

      • Suppresses completely on FLAIR

      • Does not restrict on DWI

Helpful Clues for Rare Diagnoses

  • Pituitary Macroadenoma

    • Solid ± intra- or extratumoral cysts

      • Extratumoral cysts may be trapped/enlarged PVSs or arachnoid cysts

      • Cysts often hyperdense/intense compared to CSF

    • Solid > rim enhancement

  • Pituitary Apoplexy

    • Rare; may be life-threatening (severe panhypopituitarism)

    • Necrotic pituitary with little/no enhancement (may show rim)

    • Hemorrhage may bloom on T2* (GRE, SWI)

    • Compression/edema of hypothalamus, optic chiasm/tracts may cause hyperintensity on T2WI

    • Restricts on DWI

    • Markedly hypointense on ADC

  • Astrocytoma

    • Pilocytic > > pilomyxoid astrocytoma

    • Most suprasellar astrocytomas are solid, not grossly cystic

  • Ependymal Cyst

    • Rare; 3rd ventricle least common site

    • Round/ovoid; CSF-like

  • Saccular Aneurysm

    • Aneurysms may be associated with true perianeurysmal cysts

      • Obstructed perivascular spaces posited as etiology

    • Partly or completely thrombosed may have “cystic”-appearing foci within clot

      • Rare

      • Acute thrombosis can present with panhypopituitarism, SAH

    • Imaging can mimic necrotic adenoma

      • Hypodense center, iso-/hyperintense rim on T1WI

      • Look for mixed age laminated clot

      • “Blooms” on GRE

      • Rim may enhance

Image Gallery

Sagittal T2WI MR shows EVOH with markedly enlarged lateral image, 3rd image, and 4th image ventricles. A CSF suprasellar mass caused by an enlarged 3rd ventricle was diagnosed.

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Suprasellar Cystic Mass

Full access? Get Clinical Tree

Get Clinical Tree app for offline access