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Atypical and Infrequent Sellar and Suprasellar Lesions: What the Neuroradiologist Needs to Know! Rafael Glikstein MD Bardia Moosavi MD Jorge Davila MD Mauricio Castillo MD Carlos Torres MD No Disclosures. Purpose To present atypical and infrequent pathologies that can occur in the sellar/suprasellar location, with emphasis on MR imaging findings. Approach In this pictorial review, we present several cases of atypical and infrequent diseases affecting the sellar/suprasellar region and describe the relevant imaging findings. Case 1a Craniopharyngioma • Ectodermal derived epithelial tumor (Rathke pouch remnant) • Contain cholesterol, keratin, protein, blood products, and necrotic debris • 2 Types – Adamantinomatous (90%) – Papillary (10%) • Bimodal age distribution − Peak in children 5-10 years − Peak in adults 40-50 years • Slow growth CT • Can be very large (>5cm) • Adamantinomatous: 90% cystic, 90% calcify, 90% enhance • Papillary: solid>cystic MRI • Variable T1 signal • Typically hyperintense on T2/FLAIR Case 2 2008 2013 Intracystic Mobile Nodule of Rathke’s Cleft Cyst • Ectodermal remnants of the craniopharyngeal duct • 60% suprasellar • Intracystic nodule present in 40-75% of cases, which can mimic craniopharyngioma CT • Well-defined round or oval mass • Majority are hypodense • Calcification is rare MRI • 50% hypointense, 50% hyperintense on T1W • Hyperintense on T2W/FLAIR • May have claw-like peripheral enhancement Case 3 Cyst of Liliequist Membrane • • Liliequist membrane is an arachnoid membrane from the dorsum sellae to the anterior edge of the mamillary body. It has a vertical mesencephalic segment as well. This membrane has neurosurgical importance especially in endoscopic and microinvasive surgery. Imaging Modified by Fushimi et al. Radiology 2003 • • • This membrane is not routinely visualized in imaging studies as it is very thin. However, Liliequist membrane can be visualized with heavily T2-weighted 3D constructive interference steady state (CISS) sequence. Cyst arising from Liliequist membrane can mimic Rathke cleft cyst and craniopharyngioma Case 4 Chordoid Glioma • • • • Arise from the anterior 3rd ventricle Rare tumor with both glial and chordoid feature (<1% of all gliomas) Typically occurs in middle aged adults; 2:1 F:M Visual field deficit is most common abnormality on exam CT • Hyperdense solid mass (28% may show central cystic change) • Uniform enhancement • Calcifications present in 1015% MRI • Mass separate from the pituitary and infundibulum • Iso-intense to brain on T1- and T2W • Uniform enhancement • These MRI characteristics may vary depending on the presence and degree of necrosis within the tumor Case 5 Clivus Chordoma • • • • Notochord remnant 1% of intracranial tumors May extend to nasopharynx Visual symptoms, cranial nerve palsy CT • Well-circumscribed hyperdense mass • Variable enhancement • Intratumoral dystrophic calcifications MRI • Intermediate to low signal on T1W • Typically hyperintense on T2W • Moderate enhancement Case 5 Pituitary Gangliocytoma • Slow growing neuroepithelial tumor • Most common in the temporal lobe (>75%) but can occur anywhere • 50% enhance CT • Variable density • Calcifications common (30-50%) MR • Hypo-isointense to grey matter • No surrounding edema • Variable enhancement, usually moderate Case 6 CNS Lymphoma • Primarily composed of B lymphocytes • Poor prognosis CT MR • Iso-hyperdense • Homogeneously iso-hypointense • Hemorrhage and necrosis may to cortex on T1- and T2W occur in immunocompromised − May be heterogeneous from patients hemorrhage or necrosis • Mild surrounding edema • Shows restricted diffusion • Homogenous enhancement Case 7 Pituitary Apoplexy • Hemorrhage or infarction of the pituitary gland/adenoma • Acute severe headache, visual loss • Can be life threatening due to acute adrenal insufficiency CT • Sellar/suprasellar mass with patchy or confluent hyperdensity MR • Enlarged pituitary, hyperintense on T1- and T2W in the subacute phase • “Blooming on GRE” • May show rim enhancement Case 8 Lymphocytic Hypophysitis • Idiopathic inflammation of the pituitary • 8-9:1 F:M • Delayed diagnosis and treatment may lead to death from panhypopituitarism • Steroids and replacement therapy for deficient hormones Imaging • Round pituitary gland and thick stalk (>2 mm and nontapering) • 75% show loss of posterior pituitary “bright spot” on T1W • Iso-hypointense on T2W • Uniform enhancement Case 9 Sarcoidosis • Granulomatous multisystem disorder – CNS involvement in 15% • Unknown etiology • May cause hypothalamo-pituitary dysfunction – Single hormone insufficiency or panhypopituitarism Imaging • Iso-hypointense on T1- and T2W • Sellar disease may appear cystic • Variable enhancement • 5-10% seen as hypothalamic and infundibular thickening and enhancement Case 10 50 y/o patient being treated for metastatic melanoma. Ipilimumab-Induced Hypophysitis • Autoimmune secondary hypophysitis • Ipilimumab enhances immune-mediated destruction of metastatic melanoma (FDA approved in March 2011) – Blocks CTLA-4 protein in the surface T cells – Proliferation and increase in T lymphocytes – Improves immune system for destruction of cancer cells • Life-threatening complication related to hypocortisolism • Tx: High dose steroids and hormone replacement Imaging • Pituitary enlargement ± masses • Thickening of the pituitary stalk Ipilimumab-Induced Hypophysitis Before medication Follow up During/after Case 11 Cavernous Malformation (Cavernoma) • Vascular malformation in the region of the third ventricle and tuber cinereum of the hypothalamus • Patients may present with precocious puberty and intractable epilepsy CT MR • Normal in 30-50% • “popcorn” like appearance • Well-defined hyperdense lesion • Mixed hyper-hypointense blood• 40-60% calcify containing locules on T1W • Mixed signal core and hypointense hemosiderin rim on T2W • Prominent susceptibility effect on GRE • Minimal or no enhancement Case 12 Hamartoma of the Tuber Cinereum • Non neoplastic heterotopic grey matter • Located between the mammillary bodies and infundibulum • May present with seizures, precocious puberty CT • Homogenous, isodense suprasellar mass • Calcification is uncommon MR • Hypo-isointense to grey matter on T1W • Slightly hyperintense on T2W • No enhancement Case 13 Normal Case 13 Hypermanganesemia • More common in setting of chronic liver failure but may also result from occupational exposure • Mn neurotoxicity is attributed to impaired dopaminergic, glutamatergic and GABAergic transmission, mitochondrial dysfunction, oxidative stress and neuroinflammation • Preferential accumulation in the dopaminergic cells of the basal ganglia, particularly the globus pallidus, causing extrapyrramidal motor dysfunction Imaging • High T1W signal in the adenohypophysis, hypothalamus and mesencephalon due to accumulation of manganese • No contrast enhancement Summary Diverse pathologic processes that infrequently affect the sellar/suprasellar structures have characteristic features on MR, which help in narrowing the differential diagnosis. 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