Cystic Intrasellar Mass

Anne G. Osborn, MD, FACR

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Cystic mass originating WITHIN sella vs. intrasellar extension from suprasellar lesion
Intrasellar extension of suprasellar lesion > cystic intrasellar mass

Helpful Clues for Common Diagnoses

Empty Sella (ES)
- Small crescent of compressed pituitary gland lines bottom of sella turcica
- “Primary” ES considered normal variant
- “Secondary” = surgery, pituitary infarction
Intracranial Hypertension, Idiopathic
- “Pseudotumor cerebri” F > > M
- Empty sella ± dilated optic nerve sheaths, small ventricles

Helpful Clues for Less Common Diagnoses

Obstructive Hydrocephalus
- Anterior recesses of 3rd ventricle enlarge
  - Herniate inferiorly into sella
  - If chronic may expand, erode bony sella
Rathke Cleft Cyst
- Usually < 1 cm; can be giant, erode sella
- 45% have “intracystic nodule”
- ± “Claw sign” (enhancing rim of pituitary around nonenhancing cyst)
Craniopharyngioma
- Truly intrasellar craniopharyngioma rare
- If no Ca++ difficult to distinguish from Rathke cleft cyst
Arachnoid Cyst (AC)
- Truly intrasellar AC rare
- Usually extension from suprasellar AC
Epidermoid Cyst
- Suprasellar location < off-midline
Neurocysticercosis Cyst
- Suprasellar cysts → intrasellar

Helpful Clues for Rare Diagnoses

Pituitary Apoplexy
- Can be life-threatening (secondary to pituitary insufficiency)
- Acutely may present as necrotic, rim-enhancing mass
Saccular Aneurysm (Thrombosed)
- Medially projecting from cavernous ICA
- If thrombosed may appear low signal intensity on T1 C+ scans