Suprasellar Mass, General

Anne G. Osborn, MD, FACR

DIFFERENTIAL DIAGNOSIS

Common

Pituitary Macroadenoma
Meningioma
Saccular Aneurysm
Craniopharyngioma
Pilocytic Astrocytoma

Less Common

Dilated Third Ventricle
Arachnoid Cyst
Neurocysticercosis
Rathke Cleft Cyst
Neurosarcoid
Langerhans Cell Histiocytosis
Germinoma
Dermoid Cyst
Lipoma

Rare but Important

Lymphocytic Hypophysitis
Tuber Cinereum Hamartoma
Epidermoid Cyst
Pituicytoma
Diffuse Astrocytoma, Low Grade
Pilomyxoid Astrocytoma
Ectopic Neurohypophysis
Metastasis
Lymphoma, Metastatic
Leukemia
Cavernous Malformation
Tuberculoma
Pituitary Abscess

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Is mass arising from pituitary or other site?
Does it mostly involve infundibular stalk?
Is patient adult or child?

Helpful Clues for Common Diagnoses

Most common diagnoses (“big five”) account for > 75% of all suprasellar masses
Pituitary Macroadenoma
- Most common of all suprasellar masses = suprasellar extension of macroadenoma
- Gland, mass can’t be separated
- Cystic, hemorrhagic changes common
- Mass is the pituitary gland
Meningioma
- Arises from diaphragma sellae
- Thin black line (diaphragma sellae) separates mass from pituitary
- “Dural tail sign”
  - Not pathognomonic but highly suggestive
  - Signal intensity following contrast usually > tumor itself
Saccular Aneurysm
- Most arise from circle of Willis
- Are usually slightly eccentric, not midline
- Signal intensity may be mixed
  - Partial/complete thrombosis common
  - Complex/disturbed flow may cause spin dephasing
  - Look for phase artifact
- Occasionally fusiform aneurysm/ectasia of basilar artery may project into suprasellar cistern
Craniopharyngioma
- Most common suprasellar mass in child
- Adamantinomatous subtype
- Imaging
  - 90% Ca++, 90% cystic
  - 90% enhance (rim ± nodule)
- Second peak in middle-aged adults
  - Papillary subtype
  - Solid > cystic; Ca++ uncommon
Pilocytic Astrocytoma
- Second most common suprasellar mass in children (rare in adults)
- Hypothalamus/optic pathways
- Pilocytic > > pilomyxoid type (see below)

Helpful Clues for Less Common Diagnoses

Dilated Third Ventricle
- Most common “cystic” suprasellar mass
- Third ventricle enlarged secondary to obstructive hydrocephalus
Arachnoid Cyst
- Elevates, displaces third ventricle
Neurocysticercosis
- Suprasellar cistern, sylvian fissures common sites
- Variable size cysts, enhancement
- Reactive meningeal changes may be striking (e.g., stalk thickening, vascular encasement)
Rathke Cleft Cyst
- Look for intracystic nodule
- Pituitary displaced by mass
Neurosarcoid
- Thickened stalk may be only sign
- Look for dural-based masses
Langerhans Cell Histiocytosis
- Thickened stalk, child with DI
Germinoma
- Stalk ± gland
- Can be only site but look for pineal mass
Dermoid Cyst
- Fat-like ± droplets (ruptured)
Lipoma
- Fatty mass stuck on hypothalamus
- Use fat-saturated T1WI

Helpful Clues for Rare Diagnoses

Lymphocytic Hypophysitis
- Thick, nontapering stalk ± pituitary mass
- Diabetes insipidus common
- Often occurs in peripartum females
Tuber Cinereum Hamartoma
- Clinical presentation helpful (gelastic seizures; male with precocious puberty)
- Can be “collar button” or “sessile”
- Between infundibulum (anteriorly), mammillary bodies (posteriorly)
- Signal intensity like cortex
- Does not enhance
Pituicytoma
- Low grade (WHO I) glial neoplasm of infundibulum or neurohypophysis
- M > F, most patients 40-60 years
- Hypopituitarism, visual disturbances
- Well-demarcated, homogeneously enhancing infundibular mass
Diffuse Astrocytoma, Low Grade
- Infiltrating mass difficult to distinguish from pilocytic astrocytoma (PA)
Pilomyxoid Astrocytoma
- Rare, more aggressive PA variant
- Infant/young child with bulky H-shaped suprasellar mass
- Often hemorrhages (PA, low grade do not)
Metastasis
- Gland ± stalk mass in patient with known primary
Lymphoma, Metastatic
- Destructive, infiltrative mass engulfs gland, stalk
Leukemia
- Gland/stalk + sinus mass clues
Cavernous Malformation
- “Popcorn ball” mass
- Third ventricle, optic chiasm rare sites
Tuberculoma
- TB meningitis > > frank tuberculoma in suprasellar cistern
- Focal mass w/ring enhancement common
- If caseating, mass is hypointense on T2WI
- If noncaseating, mass generally hyperintense on T2WI
Pituitary Abscess
- Very rare but potentially life-threatening
- May resemble pituitary apoplexy at imaging
  - Cystic-appearing intrasellar mass with suprasellar extension
  - Hypodense on NECT
  - Hyperintense on T2WI
  - Rim-enhancing