Making Sense of Sellar Region Pathology: Image-based Diagnostic Algorithm Ammar Chaudhry, MD Rajesh Gupta, MD Luboslav Woroch, DO Alexander Filatov, MD Robert Peyster, MD Lev Bangiyev, DO eEdE-69 SN: 960

Disclosures No relevant disclosures

Objective Review of anatomy of sellar and parasellar regions Review common indications for imaging of the pituitary gland Discuss imaging techniques of the pituitary gland Review common pathology of the pituitary gland and the adjacent structures Image-based diagnostic algorithm

Sphenoid Bone Anatomy Pituitary fossa Tuberculum sellae Optic nerve canal Chiasmatic sulcus Superior orbital fissure Anterior clinoid Posterior clinoid Greater wing of sphenoid Lesser wing of sphenoid Planum sphenoidale

Pituitary Gland Anatomy Lies within sella turcica Composed of two major parts Anterior lobe – Adenohypophysis Pars distalis – bulk of the gland, hormone secretion Pars intermedia Pars tuberalis GH, TSH, ACTH, prolactin, LH, FSH Posterior lobe – Neurohypophysis Vsopressin, oxytocin Laterally bounded by cavernous sinus Optic chiasm superiorly Diaphragma sella http://mystatdx.com

Embryology Blood Supply Posterior lobe Neural primordia Outpouching from the third ventricle Anatomic extension of the CNS Specialized glial cells pituicytes Anterior lobe Derives from the oral ectoderm Rathke’s pouch Gives rise to pars distalis and tuberalis Posterior lobe supplied by inferior hypophysial arteries Anterior lobe Little or no arterial supply Portal venous system from the pituitary stalk Venous blood from posterior pituitary Humeral regulation from the hypothalamus, posterior pituitary, and substances in the peripheral circulation

Indications for Imaging Imaging of the Pituitary Radiol Clin N Am 49 (2011) 549–571

Imaging MR Protocol

Imaging MR Demonstrate relationship to chiasm and cavernous sinus Distinguishing solid, cystic, and hemorrhagic components Vascular structures Anterior lobe is isointense to brain on T1WI and T2WI Posterior lobe is bright on T1WI and lower intensity on T2WI

Imaging Enhancement Size children (<12 years) : 6mm (upper surface flat or slightly concave) puberty : 10mm (upper surface convex; more striking in females) young adult male : 8mm female : 9mm pregnancy : 12mm older adult ( > 50 years) : gradually decreases in size

Imaging CT Calcifications Bony septa assessment for transsphenoidal pre-surgical planning Involvement of the adjacent osseous structures Contraindications to MRI

Location Based Algorhithm Common Pathology Location Based Algorhithm Parasellar Suprasellar Enhancing Craniopharyngioma Germ Cell Tumors Menigioma Aneurysm Non-enhancing Hamartoma Pituitary Stalk Lymphocytic Hypophysitis Langherhans Histiocytosis Sarcoid Mets Ectopic Posterior Pituitary Lipoma Clivus Chordoma Nasopharyngeal Carcinoma Chiasm Glioma Sellar Expanding Sella Turcica Pituitary Macroadenoma Non-expansile Intensity Hyperintense T1 Rathke’s Cleft Cyst (if protein) Dermoid Cyst (children) Hyperintense T2 Meningioma Rathke’s Cleft Cyst Hypointense T1 Pituitary Microadenoma Hypointense T2 Pituitary Apoplexy Macroadenoma Microadenoma Rathke’s cleft cyst Craniopharyngioma Langerhans Cell Histiocytosis Germinoma Apoplexy Empty sella Hypophysitis Meningioma Optic glioma Hamartoma Arachnoid cyst Epidermoid Lipoma Ectopic posterior pituitary bright spot Aneurysm Sarcoid Base of the skull tumors

55-year-old female with history of glaucoma patients was followed with serial visual field testing. The visual field deteriorated and began to show a bitemporal hemianopsia. Cor T2WI Sag Pre T1WI Cor Pre T1WI Cor Post T1WI Macroadenoma Similar imaging characteristics as microadenoma Normal pituitary tissue often not identified Expands the sella “Snowman” appearance where the waist is the imprint from rigid dura May extend into the suprasellar region and compress the chiasm May invade the cavernous sinus

19 yo female with hyperprolactinemia Dyn Cor Pre T1WI Dyn Cor Post T1WI Approximately 10% to 15 % of all intracranial neoplasms Most common sellar tumor Benign Classified based on size Microadenomas <10mm Macroadenomas >10mm Clinically classified based on endocrinological activity or lack Functional pituitary adenomas usually secrete single hormone Prolactin most common followed by GH and ACTH Microadenomas are hypovascular compare to normal pituitary tissue Microadenoma

Invasive Pituitary Adenoma Clival invasion is rare but potentially significant complication of pituitary adenoma Difficult to detect on MR imaging, easily seen on CT Risk factor for clival invasion: female sex large tumor volume null-cell subtype Larger tumor volume correlated with null-cell subtype (Mann-Whitney U test, P = .006), incidence of clival invasion (P < .001), and extent of clival invasion Clival invasion was associated with a significantly higher ratio of operative complications and recurrence After we corrected for multiple correlations, the most significant independent risk factor for clival invasion was female sex (OR = 3.62, P = .014, multinomial logistic regression), followed by large tumor volume (OR = 1.08, P < .001), and null-cell subtype (OR = 5.47, P < .001). Larger tumor volume correlated with null-cell subtype (Mann-Whitney U test, P = .006), incidence of clival invasion (P < .001), and extent of clival invasion (P = .038). Clival invasion was associated with a significantly higher ratio of operative complications (15.63%, χ2 = 7.067, P = .008) and recurrence (57.14%, χ2 = 10.739, P = .001).

40 yo male with progressive visual decline in the right eye over several weeks, presents with rapid visual loss, slight droopiness of the right eye, and severe headache. Pituitary adenoma with hemorrhage. Sag Pre T1WI Ax T2WI Cor Post T1WI Pituitary Apoplexy Lack of direct arterial supply to anterior pituitary lobe makes it susceptible to ischemia with or without hemorrhage Clinical syndrome Headache Visual changes Ophthalmoplegia Mental status change Underlying adenoma is often present

Empty Sella Patulous diaphragma sellae Aging Pseudotumor cerebri Infarction Surgery Radiation therapy Hypopituitarism is rare

25 yo female with headaches Sag Pre T1WI Sag Post T1WI Cor T2WI Cor Post T1WI Derive from Rathke’s pouch (primitive oral ectoderm) Lined by single layer of columnar or cuboidal epithelium Frequently asymptomatic May present with bitemporal hemianopsia or pituitary dysfunction Intrasellar and non-invasive May contain serous or mucoid material Serous – hypodense on CT, T1 hypointense and T2 hyperinstense Mucoid – hyperdense on CT, T1 hyperintense Rarely calcify May demonstrate mild enhancement of the wall Rathke’s Cleft Cyst

Papillary craniopharyngioma Ax Pre T1WI Ax Post T1WI Ax T2WI Sag Post T1WI 73 yo female with headache and visual disturbance Papillary craniopharyngioma 8 yo female presented with progressive double vision and papilledema Left CN VI palsy Adamantinomatous type craniopharyngioma Cor Post T1WI

Histopathologic Types of Craniopharyngiomas Benign neoplasm arising from squamous epithelial remnants of Rathke’s pouch Tend to recur and invade adjacent structures Commonly present with Headaches Endocrine dysfunction Visual disturbance Bimodal age at presentation 5 to 14 years in children 65 to 74 years in adults Usually suprasellar, but may extend into the sella Preachasmatic – visual disturbance Retrochiasmatic – increased ICP, compression of the hypothalamus and protrusion into the third ventricle Adamatinous Squamous-Papillary Location Suprasellar Intrasellar/suprasellar or suprasellar Age Children, occasionally adults Adults Tissue structure Predominantly cystic Predominantly solid T1 without contrast Hyperintense cysts typical If ever, hypointense cysts Shape Lobulated Spherical Encase vessel Yes No Tumor recurrence +++ + Calcifications Imaging characteristics Vary in size and composition Cystic and/or solid CT Enhancing solid/cystic mass Calcifications +/- MRI T1WI – vary intensity depending on contents (proteinaceous debris, cholesterol, and hemoglobin) Enhancement of the solid component T2WI – predominantly hyperintense Calcifications are hypointense on all pulse sequences

25 yo female with history of meningioma Sag Pre T1WI Sag Post T1WI Cor Post T1WI Meningioma May arise from the tuberculum sellae, anterior clinoid, diaphragma sellae, planum sphenoidale, cavernous sinus, and upper clivus Commonly present with progressive visual symptoms CT – hyperdense mass with homogenious enhancement MRI – T1 isointense, T2 iso-hyperintense, avid enhancement Distinguished from pituitary adenoma by Normal size of the sella turcica Identification of the normal pituitary tissue Can invade cavernous sinus with narrowing and/or occlusion of ICA Hyperostosis Ax T2WI Ax Post T1WI

6 yo male with progressive left eye vision loss over a year Ax Pre T1WI Cor Pre T1WI Cor Post T1WI Cor Post T1WI Optic Glioma Tumor of childhood Majority benign and slow growing Often associated with NF1 Separate from pituitary gland T1 isointense and T2 hyperintense with variable enhancement Presence of cystic component suggests JPA Cor T2WI

21 yo male presented with progressive vomiting, polyuria and polydipsia for months, progressive loss of his peripheral vision in both eyes bitemporal inferior quadrantsanopsia, panhypopituitarism and diabetes insipidus HCG serum ↑, BhCG CSF ↑ ↑ ↑ Sag T2WI Sag Pre T1WI Sag Post T1WI Cor Post T1WI Germ Cell Tumor Lesion of childhood and young adults MR Findings Germinoma is the most common type T1WI – Iso-/hyperintense to gray matter 20 % in sellar/suprasellar region and remainder in pineal region T2WI – Iso-/hyperintense to gray matter Calcification, hemorrhage (rare) Commonly present with DI, hypopituitarism, and optic chiasm compression DWI: Restricted diffusion due to high cellularity CT – hyperdense and homogeneously enhancing Strong, homogeneous enhancement, ± CSF seeding, ± brain invasion

Lymphocytic Hypophysitis 23 yo female with hypopituitarism Cor T2WI Sag Pre T1WI Sag Post T1WI Cor Post T1WI Lymphocytic Hypophysitis Inflammatory disease of the pituitary Can involve infundibulum Young women during late pregnancy or postpartum Imaging shows enlarged enhancing pituitary gland and thickened infundibulum May regress spontaneously or with steroids

Hamartoma of the Tuber Cinereum 2 yo female with gelastic sezures consisted of laughing, turning her head to left side and tonic motor activity of the extremities Sag Pre T1WI Sag Post T1WI Ax FLAIR Ax T2WI Hamartoma of the Tuber Cinereum Congenital non-neoplastic heterotopias Known cause of Precaucious puberty due to secretion of LH-releasing hormone Gelastic seizures may be related to connection of the lesion with limbic system or possibly presence of other abnormalities (callosal agenesis, heterotopias, and microgiria) Just anterior to mamillary bodies T1 isointense and T2 hyperintense to gray matter Do not enhance, calcify, or contain cysts

Langerhans Cell Histiocytosis 13 yo male presented with diabetes insipidus Sag Post T1WI Cor Post T1WI Langerhans Cell Histiocytosis Proliferation of Langerhans cell histiocytes forming granulomas within any organ system Etiology: Uncertain: Inflammatory ↔ neoplastic Peak age at onset 1 year (isolated), 2-5 years (multifocal disease) Common presentation – DI, ± visual disturbance, ± hypothalamic dysfunction On imaging thick enhancing infundibulum, absent posterior pituitary bright spot

Lymphocytic Hypophysitis 23 yo female with hypopituitarism Cor T2WI Sag Pre T1WI Sag Post T1WI Cor Post T1WI Lymphocytic Hypophysitis Inflammatory disease of the pituitary Can involve infundibulum Young women during late pregnancy or postpartum Imaging shows enlarged enhancing pituitary gland and thickened infundibulum May regress spontaneously or with steroids

Granulomatous Disease Sarcoid, TB, Wegener etc. Cranial nerve involvement Cannot be differentiated by imaging Sarcoid may present with sellar or suprasellar mass and masquerade as pituitary adenoma or meningioma

Epidermoid Cystic lesion filled with keratin Ax T2WI Ax FLAIR Sag Pre T1WI Ax DWI Cystic lesion filled with keratin Signal characteristics are similar to CSF on T1 and T2, however not FLAIR Show restricted diffusion Usually do not enhance Insinuate throughout the suprasellar region

Lipoma Characterized by T1 hyperintensity due to fat Lipomas are usually circumscribed Teratomas and dermoids can grow large and compress adjacent structures Teratomas may contain calcification or ossification Sag Pre T1WI Incidentally found lipoma. Patient was imaged for headache.

58 yo male with jerking motions during sleep and progressive memory loss. No visual changes or endocrine symptoms Sag Post T1WI Ax NECT Sag Pre T1WI Chordoma Imaging CT Soft tissue mass with bone destruction and calcifications MRI T1WI – isointense to brain parenchyma with hypointense calcifications T2WI – hyperintensity is a rule Enhance Cor T2WI

Metastasis 53 yo female with history of breast CA Ax Pre T1WI Ax T2WI Sag Post T1WI 53 yo female with history of breast CA

Aneurysm 51 yo male with acute onset of headache and left CN III palsy NECT Ax Pre T1WI Cor Post T1WI Ax T2WI 51 yo male with acute onset of headache and left CN III palsy Lat Lt CCA AP Lt CCA

CONCLUSION Location Sellar Intensity Isointense T1 Hypo T2 -subacute (hyper T1/T2) -comp of adenoma Pit apoplexy Hyperintense T2 Gender Both Pituitary Macroadenoma - >10 mm -mild enhancement Female Enhancement Intense -can be suprasellar Meningioma -Calcify Rare Rathke’s Cleft cyst Hypointense T1 Pituitary Microadenoma - <10 mm -hypoenhancement Hyperintense T1 Male Dermoid Cyst -Children -Calcify Rathke’s cleft cyst -if protein content -Adults Eccentric mass (cavernous carotid aneurysm) Suprasellar Heterogeneous Craniopharyngioma -solid – enhances -cystic – high T1/T2 -bimodal age -calcify Homogeneous -uniform enhancement Germ Cell Tumors -iso T1/T2 Pituitary Stalk Young age Histiocytosis (Eosinophilic Granuloma) Hypo T1/hyper T2 Mets -enhances Iso T1/T2 Sarcoid -enhances -female Lymphocytic Hypophysitis Chiasm/ Hypothalamus Yes -hyperintense FLAIR -iso T1/hyper T2 -young age Glioma No -floor of 3rd vent Hamartoma

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