EXPERT DIFFERENTIAL DIAGNOSIS:

Transcription

1 EXPERT DIFFERENTIAL DIAGNOSIS: Sellar Region Anne G. Osborn, M.D.

2 DISCLOSURE: Published RSNA 2008

3 SELLA, PITUITARY: Normal Gross, 3T Anatomy

4 SELLA, PITUITARY: Anatomically-Based Differential Diagnoses Intrasellar Sella/pituitary, normal variants Enlarged pituitary gland Intrasellar lesion Cystic intrasellar mass Suprasellar Suprasellar mass, general Suprasellar mass, pediatric Suprasellar cystic mass Calcified suprasellar mass Thick infundibular stalk

5 SELLA/PITUITARY: Normal Variants Common Pituitary hyperplasia (physiologic) Pituitary incidentaloma Empty sella Less common Bright pituitary gland Absent posterior pituitary bright spot Small sella turcica J -shaped sella Rare but important Paramedian ( kissing ) internal carotid arteries

6 PITUITARY HYPERPLASIA (PHYSIOLOGIC) Must know age, gender!! Physiologic mm Convex upwards Strong, uniform enhancement Can be indistinguishable from Macroadenoma Lymphocytic hypophitis Metastasis, lymphoma Beware: Macroadenoma in prepubescent males! Postpartum lactating 14 mm 11 mm 21y menstruating

7 PITUITARY INCIDENTALOMA Inhomogeneous or nonenhancing filling defect 15-20% normal MRs Can also be transient Etiology Nonneoplastic cyst (e.g., pars intermedia, Rathke cleft) Nonfunctioning microadenoma (common at autopsy)

8 EMPTY SELLA Primary (i.e., not post-surgical) Courtesy M. Sage

9 MISCELLANEOUS NORMAL VARIANTS Bright pituitary Shallow sella Small sella Kissing carotids

10 ENLARGED PITUITARY Common Pituitary hyperplasia Microadenoma Macroadenoma Less common Neurosarcoid LCH Lymphocytic hypophysitis Macroadenoma mimics Rare but important Intracranial hypotension Meningioma Metastasis davf Pituicytoma Pseudotumor Lymphoma Leukemia

11 ENLARGED PITUITARY Neurosarcoid LCH Lymphoma Pseudotumor

12 ENLARGED PITUITARY Macro mimic ( shallow sella ) Intracranial hypotension Lymphocytic hypophysitis Metastasis

13 INTRASELLAR LESION Common Pituitary hyperplasia Microadenoma Empty sella Less common Macroadenoma Rathke cleft cyst Craniopharyngioma Neurosarcoid Rare but important Lymphocytic hypophysitis Intracranial hypotension Kissing carotids Aneurysm Meningioma Metastasis Lymphoma davf CNS siderosis ( black pituitary) Hepatic encephalopathy ( white pituitary )

14 Variable histology Prolactinoma 30% GH 20% Null cell 20% ACTH 10% FSH/LH 10% PRL-GH 5% Mixed, TSH 1-5% MICROADENOMA Incidental pituitary lesions are common 17% in autopsy series

15 MICROADENOMA Pituitary Microadenoma 10mm or less 10-20% of autopsies Micro >>> Macro Dynamic Imaging Increases sensitivity (10-30% seen only on dynamic MR) Enhances slower than normal gland

16 MICROADENOMA

17 RATHKE CLEFT CYST Intrasellar 40% Suprasellar extent 60% 3mm 3cm Most incidental Symptomatic Pituitary dysfunction Visual change, HA Look for Intracystic nodule Claw sign

18 MISCELLANEOUS INTRASELLAR LESIONS Craniopharyngioma Completely intrasellar is rare Variable signal Craniopharyngioma CNS siderosis Black pituitary on T2* Iron overload states >> SAH Thalassemia Hemochromatosis Siderosis

19 CYSTIC-APPEARING INTRASELLAR MASS Common Empty sella Intracranial hypertension, idiopathic Less common Obstructive hydrocephalus Rathke cleft cyst Craniopharyngioma Arachnoid cyst Epidermoid cyst Neurocysticercosis Rare but important Pituitary apoplexy Saccular aneurysm (thrombosed)

20 CYSTIC INTRASELLAR MASS Key question Cystic mass originating WITHIN sella? Intrasellar extension from suprasellar cystic lesion Intrasellar extension of suprasellar lesion >> cystic intrasellar mass

21 INTRACRANIAL HYPERTENSION (IDIOPATHIC) A.k.a. pseudotumor cerebri ICP without underlying pathology Young obese female Imaging Partial empty sella Dilation/tortuosity of optic n. sheath Posterior globe flattened Subarachnoid spaces, sulci Small ( slit-like ) ventricles seen in only 10%

22 INTRASELLAR CYSTIC LESIONS Hydrocephalus Craniopharyngioma Epidermoid cyst Rathke cleft cyst

23 INTRASELLAR CYSTIC LESIONS Arachnoid cyst Neurocysticercosis Pituitary apoplexy (Sheehan) Thrombosed aneurysm

24 SUPRASELLAR MASS, GENERAL Common Macroadenoma Meningioma Saccular aneurysm Craniopharyngioma Pilocytic astrocytoma Less common Dilated 3 rd ventricle Arachnoid cyst Neurocysticercosis Rathke cleft cyst Neurosarcoid LCH Germinoma Dermoid cyst Lipoma Rare but important Lymphocytic hypophysitis Pituitary apoplexy Tuber cinereum hamartoma Epidermoid cyst Pituicytoma Diffuse astrocytoma Pilomyxoid astrocytoma Ectopic neurohypophysis Metastasis Lymphoma Leukemia Cavernous malformation Tuberculoma Pituitary abscess

25 SUPRASELLAR MASS, GENERAL Big 5 = 75% The big kahuna Macroadenoma (35%-50%) Approximately 10% Meningioma Aneurysm Craniopharyngioma Astrocytoma (hypothalamicchiasmatic)

26 SUPRASELLAR MASS, GENERAL: Key Questions to Consider Is the patient adult or child? Is the mass intra- or extra-axial? If extra-axial, does it arise from pituitary? Can you identify pituitary gland separate from mass? Or is the gland the mass? Does it mostly involve the infundibular stalk? Intra-axial masses arise from Optic chiasm, hypothalamus 3 rd ventricle Is the mass cystic or solid? If cystic, is it exactly like CSF?

27 SUPRASELLAR MASS, PEDIATRIC Common Pilocytic astrocytoma Craniopharyngioma Pituitary hyperplasia Hydrocephalus ( 3 rd v.) Less common Germinoma Tuber cinereum hamartoma Arachnoid cyst LCH Stalk anomalies Teratoma Rare but important Lipoma Macroadenoma Dermoid cyst Pilomyxoid aneurysm Saccular aneurysm Trilateral retinoblastoma Lymphocytic hypophysitis Lymphoma/leukemia Rathke cleft cyst

28 PILOCYTIC ASTROCYTOMA

29 CRANIOPHARYNGIOMA 2nd most common suprasellar mass in children Peak incidence 5-15 yrs Second peak yrs M = F Visual changes Endocrine dysfunction Mass effect H/A, N, V, papilledema Imaging 90% Ca++, 90% cystic 90% enhance Cysts variable intensity

30 Suprasellar region is second most common site M = F suprasellar 90% present < 20 yrs Endocrine dysfunction Diabetes insipidus Panhypopituitarism Radiosensitive Up to 90% 10 survival GERMINOMA

31 GERMINOMA Imaging Combined lesion typical but may affect only infundibular stalk May be hyperdense (CT) Isointense T1WI Hyper- to isointense T2WI Enhances homogeneously CSF dissemination common

32 TUBER CINEREUM HAMARTOMA Clinical Precocious puberty Usually < 2yrs Gelastic seizures M > F Pallister-Hall Facial anomalies Polydactyly Imperforate anus Pathology Congenital nonneoplastic heterotopia Between infundibular stalk, mamillary bodies

33 TUBER CINEREUM HAMARTOMA

34 SUPRASELLAR CYSTIC MASS Common Hydrocephalus ( 3 rd v) Arachnoid cyst Craniopharyngioma Neurocysticercosis Less common Rathke cleft cyst Dermoid cyst Epidermoid cyst Enlarged PVSs Rare but important Macroadenoma Pituitary apoplexy Astrocytoma (pilocytic, pilomyxoid) Ependymal cyst Saccular aneurysm (partially/completely thrombosed)

35 Arachnoid cyst HYDROCEPHALUS vs. ARACHNOID CYST Hydrocephalus 3 rd v easily identified, dilated May project into sella Signal CSF-like Hydrocephalus Arachnoid cyst 10% suprasellar 3 rd v elevated/compressed, often difficult to identify CSF may be slightly different signal from cyst

36 RATHKE CLEFT CYST 60% suprasellar Variable size Can be tiny (intrapituitary) Can be huge!! May widen, erode sella Variable signal Look for Intracystic nodule Claw sign

37 MISCELLANEOUS SUPRASELLAR CYSTS, CYSTIC-APPEARING MASSES Craniopharyngioma Neurocysticercosis Astrocytoma Pituitary apoplexy

38 CALCIFIED SUPRASELLAR MASS Common Atherosclerosis Craniopharyngioma Meningioma Aneurysm (saccular, fusiform) Less common Neurocysticercosis Pilocytic astrocytoma Dermoid cyst Rare but important Macroadenoma Tuberculosis Chondroid tumor

39 CALCIFIED SUPRASELLAR MASS Key questions Is Ca++ curvilinear, punctate, globular? Does lesion enhance?

40 CALCIFIED SUPRASELLAR MASS: Atherosclerosis Atherosclerosis Older patient Curvilinear Ca++ Bilateral, multifocal Aneurysm Saccular (ring, arc) Fusiform (curvilinear) Ca++

41 CALCIFIED SUPRASELLAR MASS: Miscellaneous Craniopharyngioma Meningioma Dermoid cyst Macroadenoma

42 THICK INFUNDIBULAR STALK: Key Issues Know what normal stalk looks like! Tapers from top to bottom 2 mm or less diameter Thick stalk > 2mm Nontapering Patient age extremely important Child = LCH, germinoma Adult = sarcoid, hypophysitis, pituicytoma, metastasis, lymphoma

43 THICK STALK Child Adult Germinoma Sarcoid Histiocytosis Lymphoma

44 SUMMARY Know patient age, clinical/lab Determine lesion sublocation Intrasellar Suprasellar Infundibular stalk Remember the Big Five Find pituitary separate from mass? No (if gland is mass, consider macroadenoma, metastasis, hypophysitis, lymphoma) Yes (consider meningioma, aneurysm, cyst, etc.)