Not an Adenoma, Now What?: A review of non-adenomatous sellar lesions Sara Koenig, MD Carlos Bazan, MD

Disclosures Sara Koenig – no financial interests to disclose. Carlos Bazan – no financial interests to disclose.

Purpose The purpose of this exhibit is to review the wide differential of non-adenomatous lesions of the sella with relevant individual clinical imaging cases. Greater than 90% of sellar lesions are adenomatous. However, not all pituitary lesions are adenomas.

Approach/Methods A retrospective review of neuroradiology cases at the University of Texas Health Science Center at San Antonio was performed to identify cases of non-adenomatous sellar lesions based on imaging characteristics, some with confirmed pathologic tissue diagnosis. Additionally, a review of literature of sellar lesions was performed. Lesions were classified into four categories: Congenital Neoplastic Vascular Infectious

CONGENITAL SELLAR LESIONS Empty Sella Rathke’s Cleft Cyst Sellar Spine Cephalocele Transected Stalk Epidermoid Cyst Hypothalamic Hamartoma Lipoma

Empty Sella XR Due to protrusion of an arachnoid lined CSF-filled portion of the suprasellar cistern through wide diaphragma sellae into the bony sella turcica. Filled partially with CSF Rarely completely "empty“. Pituitary gland is almost never completely absent. Case Imaging Findings: Skull radiographs demonstrate a ballooned sella with undercutting anteriorly. CT images demonstrate a large sella, hypodense. CT CT

Empty Sella (continued) MR images demonstrate a sella filled with cerebrospinal fluid with thin rim of pituitary tissue. Dark CSF on T1. Bright CSF on T2. Dark CSF on T1 + Gd and normal enhancement of remaining pituitary tissue (arrow). T1 T2 Gd

Rathke's Cleft Cyst T1 T1 T2 Gd Gd Gd Nonenhancing, noncalcified, intra-/suprasellar cyst with intracystic nodule. Completely intrasellar (40%), suprasellar extension (60%). Density/intensity varies with cyst content (serous vs. mucoid). Most symptomatic when at 5-15 mm in diameter. Case Imaging Findings: T1W and post contrast images demonstrate “claw sign,” an enhancing rim of compressed pituitary surrounding a nonenhancing cyst. T2W images demonstrate a hypointense cystic lesion. T1 T1 T2 Gd Gd Gd

Sellar Spine CT A sellar spine is an anatomical variant characterized by an osseous spine that arises in the midline from the dorsum sellae and protrudes into the pituitary fossa. Case Imaging Findings: CT images demonstrate the osseous spine protruding into the pituitary fossa (arrows). T1W axial image demonstrates the osseous spine appearing isointense to the skull and hyperintense to brain parenchyma, protruding into the sella. T1 CT

Transphenoidal Cephalocele CT CT Cisternogram Rare 1 in 700,000. Assoc with other midline defects: cleft palate, CC dysgenesis, hypertelorism. Present with craniofacial deformities, CSF rhinorrhea, meningitis. T1 sag and cor images help define the lesion. CT better for defining bone defect and cisternography shows continuity with subarachnoid space. T1 T1

Transected Stalk Case Imaging findings: T1 T1 T1 Associated with breech deliveries in children. In adults can be acquired by head trauma. Typically presents with hormone deficiency in both children and adults. Case Imaging findings: Small anterior pituitary gland is demonstrated in the sagittal T1W image below. Absence or hypoplasia of pituitary stalk, as is shown below on the T1W images. T1 T1 T1

Epidermoid Cyst CT CT CT An epidermoid cyst is a congenital inclusion of ectodermal epithelial elements. Case Imaging Findings: CT images demonstrate a sellar hypodense lesion. T1W images demonstrate an isodense sellar lesion with post contrast pituitary rim enhancement. T2W images demonstrate heterogenous hyperintense signal, as expected with a cyst. T1 T2 Gd

Hypothalamic Hamartoma Gd Caused by congenital gray matter heterotopia in region of tuber cinereum (arrow). Also known as a tuber cinereum hamartoma. Can be either sessile or pedunculated. Classically a mass located between mammillary bodies and infundibulum. Case Imaging Findings: Nonenhancing hypothalamic mass contiguous with tuber cinereum. Isointense to gray matter on T1/T2. Gd T2

Lipoma T1 T1 Rare cause of sellar region lesions. Congenital abnormal rest of fat cells due to abnormal resorption of the meninx primitiva. Has classic fat MR signal. Case Imaging Findings: T1W image demonstrates a well circumscribed rounded hyperintense suprasellar lesion. T2W image demonstrates a hypointense suprasellar lesion, consistent with fat. T2

NEOPLASTIC LESIONS Meningioma Germ cell tumor – Germinoma Craniopharyngioma Chiasm Astrocytoma Pituicytoma Schwannoma Lymphoma Teratoma Metastasis

Meningioma T1 T2 Gd Well circumscribed mass about the sella with MR characteristics of a meningioma. Case Imaging Findings: T1W images demonstrate a mass isointense to brain parenchyma. T2W images demonstrate a lesion nearly isointense to gray matter. T1W post contrast images demonstrate an intensely enhancing sellar/suprasellar mass consistent with a meningioma (arrow).

Germ Cell Tumor: Germinoma Germinal cell tumor of the CNS. 80-90% of CNS germinomas are midline near 3rd ventricle May have multiple locations, such as sellar and pineal (arrows). Case Imaging findings: Isointense sellar lesions on T1 and T2 images with associated mild dilatation of the third ventricle. Post contrast images demonstrate intense homogenous enhancement. Although not shown, restriction on DWI is expected. T1 Gd T2 Gd Gd Gd

Craniopharyngioma T1 T1 FLAIR Gd Gd T2 Benign, usually partially cystic sellar tumor. Derived from the Rathke pouch epithelium. There are 2 types: Adamantinomatous, cystic, in children. Papillary – solid, in adults. Common Imaging Findings Large multilobulated sellar mass. Frequently >5cm in size. Ca++ common in children. MR signal changes with the contents. Case Imaging Findings: T1W images demonstrate an iso to hyperintense cystic lesion with scattered hypointense dark foci consistent with Ca++. T2W images demonstrate a sellar lesion with predominant cystic component. Intense epithelial/cyst wall enhancement with faint enhancement of solid components. Gd Gd T2

Chiasm astrocytoma Occurrence: Case Imaging findings: T1 FLAIR T2 T1 60% cerebellum. 25-30% optic nerve/chiasm. 10-15% along the third ventricle or brain stem. Case Imaging findings: T1W images demonstrate a large heterogeneous predominantly solid mass in the suprasellar region isodense to parenchyma. T2 and FLAIR images demonstrate a heterogeneous mass with solid components hyperintense to gray matter and cystic components vs. necrosis isointense to CSF. T1 + Gd images demonstrate an intensely enhancing suprasellar mass with central cystic formation vs. necrosis. T1 FLAIR T2 T1 Gd T2*

Pituicytoma T1 T2 Rare tumor that arises from pituicytes in the posterior pituitary/stalk. 20% are intrasllar, 40% are suprasellar, and 40% are combined. Case Imaging Findings: T1 isointense lesion. T2 hyperintense lesion Strong uniform enhancement. Case courtesy of Geoffrey Fletcher, MD This is a tumor that I was not familiar with until recently; only about 50 symptomatic cases have been reported in the lierature. Gd Gd

Schwannoma – 5th Cranial Nerve Benign nerve sheath tumor composed of neoplastic Schwann cells. Locations: 99% of all schwannomas are along cranial nerves. 95% involve the vestibulocochlear nerve. < 1% of all intracranial schwannomas are intraparenchymal. Case Imaging findings: T1W image demonstrates a parasellar mass along CN5 with classic isointensity. T2W image demonstrates a parasellar mass along CN5 with classic hyperintensity. Post contrast image demonstrates a parasellar intensely enhancing mass arising from the CN5. T1 T2 Gd

Lymphoma CNS malignancy due to proliferation of B-cells. 98%are diffuse large B-cell, non-Hodgkin lymphoma. Case Imaging Findings: A lateral skull radiographs demonstrates an enlarged osseous sella. CT shows an isodense-to-parenchyma lesion with enhancement. CT- CT+

Lymphoma (continued) T1W images demonstrate a large isointense sellar mass. T2W images demonstrate an isointense-to- gray matter homogenous mass. Contrast enhanced images demonstrate an enhancing pituitary mass. This lesion was biopsy to proven to be lymphoma. T1 T2 Gd

Teratoma Most common perinatal brain tumor. Male > Female prevalence. Case Imaging findings: T1W images demonstrate a hetrogeneous mass with bright foci of fat and hypointense regions consistent with Ca++. T2W images demonstrate a heterogeneous primarily hyperintense mass (both fat and fluid components are bright). Contrast enhanced images demonstrate an intensely enhancing mass with demonstration of Ca++. T2 Gd T1

Metastasis T1 T1 Gd T1 Gd Gd Typically breast or lung cancer. 6-8% of breast metastasis. Case Imaging Findings: T1W image demonstrates a sellar/suprasellar mass isointense to parenchyma. Post contrast images demonstrate an enhancing sellar/suprasellar mass. This lesion resected and found to be metastatic hepatocellular carcinoma. T1 Gd Gd

Vascular Aneurysm Pseudoaneurysm Kissing Carotids Carotid-Cavernous fistula

Carotid Cavernous Aneurysm CT Rare intracranial aneurysms. May cause erosion of the lateral sellar margin or compression of the pituitary gland. Case Imaging Findings: CT images demonstrate an isodense intrasellar lesion. T1W MR demonstrates flow void in the suprasellar region, which is the key diagnostic clue. There is compression of the pituitary gland. ******stats T1 T1

Carotid Cavernous Aneurysm (continued) CTA Carotid Angio Cavernous internal carotid artery (ICA) aneurysms represent approximately 3-5% of all intracranial aneurysms. Can arise from any segment of cavernous carotid. Most common in the horizontal ICA segment. Case Imaging Findings: CTA and Carotid angiography demonstrate a large intrasellar carotid cavernous aneurysm.

Pseudoaneurysm CTA Carotid Angio A pseudoaneurysm is defined as a focal arterial dilatation not contained by the normal arterial wall. A postoperative complication of adenoma or other mass resection. Case Imaging Findings: CTA and carotid angiography demonstrates a hypervascular lesion within a partially resected adenoma (orange arrow) consistent with a pseudoaneurysm (blue arrow).

Kissing carotids T2 Medially deviated supraclinoid/cavernous carotid arteries are in close approximation in the midline, or “kissing” carotids. Case Imaging Findings: A T2 weighted image demonstrates closely approximated cavernous carotid flow voids consistent with “kissing” carotids (arrow).

Carotid-Cavernous Fistula Nontrauamtic or traumatic arteriovenous shunt in the cavernous sinus. Case Imaging Findings: Arteriogram images demonstrate a carotid cavernous fistula. Also note postsurgical craniotomy changes of recent epidural hematoma evacuation.

Infectious Sarcoidosis Histiocytosis Lymphocytic hypophysitis Abscess

Sarcoidosis T1 Gd Post Therapy Gd Gd Gd Systemic disorder with granulomas in multiple organ systems CNS Locations: 35% are dural 35% are leptomeningeal 30% are within the cranial nerves, pituitary, or hypothalamus T1 Isointense T2 Hypointense or hyperintense foci. Hypointense when with fibrocollagenous/gliotic tissue Hyperintense when contains Inflammatory tissue Case Imaging Findings T1 image demonstrates an enlarged infundibulum (orange arrow). Post contrast images demonstrate an Intensely enhancing infundibulum and enlarged VR spaces (blue arrow). Post treatment T1 image with normal size of the infundibulum. Post Therapy Gd Gd Gd

Histiocytosis Proliferation of histiocytes FLAIR Proliferation of histiocytes Forms granulomas in hypothalamus and pituitary gland. Presents with: Visual disturbance Endocrine dysfunction Diabetes insipidus Common Imaging findings: Thick pituitary stalk. Hypothalamic mass. Posterior lobe bright spot often absent. Case Imaging Findings: Images demonstrate a T1 hypointense, FLAIR hyperintense, and intensely enhancing hypothalamic chiasmatic mass. ********************needs contrast images Gd Gd

Lymphocytic Hypophysitis Caused by granulomatous inflammation, typically in post partum women. Common imaging findings: Thick stalk (> 2 mm). Loss of normal tapering ± enlarged pituitary gland. 75% show loss of posterior pituitary "bright spot“ on T1. T2 iso to hypointense. T1 + Gd with intense enhancement usually. Case imaging findings: Case of lymphocytic hypophysitis with intensely enhancing enlarged pituitary gland which is isointense on T1 and iso to hyperintense on T2. The lesion was biopsy proven to be lymphocytic hypophysitis. T2 Gd T1

Pituitary Abscess Pituitary infections are very rare. Infectious route: Hematogenous. Spread from infected sphenoid sinus or cavernous sinus. Often predisposing mass. Presents with headache and visual disturbance. Common imaging findings: Similar to microadenoma Ring enhancing capsule. Case imaging findings: A hypoenhancing lesion in the pituitary, representing abscess secondary to sphenoid sinus infection, confirmed at surgery.

Summary There is a wide differential that should be considered when evaluating sellar lesions. It is important to correlate these imaging findings with the clinical presentation. Not all pituitary and sellar lesions are adenomas!

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