Presentation on theme: "Congenital Abnormalities of the Sellar and Parasellar Regions"— Presentation transcript:
1Congenital Abnormalities of the Sellar and Parasellar Regions Division of NeuroradiologyDepartment of RadiologyUniversity of North Carolina at Chapel Hill
2PurposeTo present the imaging appearances of congenital diseases arising in the sellar and suprasellar regionsTo demonstrate how the embryological correlations of the pituitary gland with the adjacent structures facilitate the correct interpretation of sellar and parasellar congenital abnormalities
3EmbryologyThe pituitary gland consists of two embryological and functionally distinct divisions:Adenohypophysis (pars anterior, pars intermedia and pars tuberalis)Neurohypophysis (median eminence, infundibular stem and pars posterior)
4EmbryologyDevelopment of the pituitary gland begins in the 4th week of life with inductive signals from the diencephalon initiating the formation of Rathke's pouchRathke’s pouch has been considered as a diverticulum of the epithelium lining of the stomodeum but recent evidence indicates it is a derivative of neural ectoderm from the anterior neural ridge
5EmbryologyBy the 8th week of life, the primitive adenohypophysis separates from the oral cavity and primitive pituitary cells undergo rapid proliferation with differentiation into specialized hormone linesAdenohypophysis consists of: pars anterior or distalis, pars intermedia (rudimentary in humans) and pars tuberalis (along the stalk)
6EmbryologyNeurohypophysis originates from a neuroectodermal evagination of tissue in the diencephalic floor which grows to the stomodeal roof. An extension of the 3rd ventricle (the infundibular recess), persists in the neuroectodermal diverticulum of the forebrainNeurohypophysis is divided into median eminence, infundibular stem and pars posterior
7EmbryologyFigure 1A. 6-week embryo shows the dual origin of the gland from Rathke's pouch and from diencephalic floor (infundibulum) (used with permission).Sadler, T., Susceptible periods during embryogenesis of the heart and endocrine glands. Environ Health Perspect, 2000; 108: 555
8EmbryologyFigure 1B. Pituitary at 11 weeks of life. The gland is formed and a cleft persists between pars intermedia and pars anterior. The craniopharyngeal canal closes and occasionally the adenohypophysis remains in the nasopharynx (used with permission).Sadler, T., Susceptible periods during embryogenesis of the heart and endocrine glands. Environ Health Perspect, 2000; 108: 555
9EmbryologyFigure 1C. Pituitary gland at 16 weeks of life. The gland acquires an ‘adult’ configuration and the craniopharyngeal canal closes (used with permission).Sadler, T., Susceptible periods during embryogenesis of the heart and endocrine glands. Environ Health Perspect, 2000; 108: 555
10EmbryologyRegulation of pituitary embryogenesis involves a cascade of genes expressed during the 4th week of life in the diencephalon initiating formation of Rathke‘s pouch and later a combined expression of multiple genes throughout the stomodeal epithelium required for morphogenesis of the pouch and proliferation and differentiation of hormone specific cells
11Newborn Pituitary Gland In neonates the pars anterior and pars posterior are both uniformly bright on the T1 imagesAt birth the pituitary gland may also be globular in shapeThis appearance likely reflects the hormonal surges that occur perinatallyThe signal intensity and size of the pituitary gland becomes similar to older children’s appearance by two months of age
12Newborn Pituitary Gland Figure 2. Sagittal non-contrast T1 image shows pituitary gland at 5 days of age. Until 2 months of age, the pituitary gland is uniformly bright
13Abnormal Separation of Ectoderm and Neuroectoderm
14Transsphenoidal Encephalocele It is an “occult” encephalocele characterized by a bone defect in ethmoid or sphenoid boneUsually diagnosed later than other forms of encephalocelesHypothalamus, pituitary gland, 3rd ventricle, optic nerves and chiasm may be located in the encephalocele sacTypical clinical presentation: nasal obstruction, difficulty feeding and failure to thrive
15Transsphenoidal Encephalocele A BFigure 3. Sagittal post-Gd T1 (A) and T2 (B) images show herniation of a CSF-filled sac (white arrows) through a bone defect in the body of the sphenoid. The neurohypophysis (black arrow) is also noted. Agenesis of the corpus callosum (C/o of Dr. A. Rossi).
16Congenital Abnormalities Development of the Hypothalamo-Pituitary Axis
17Hypoplastic Pituitary Gland Pituitary hypoplasia is a congenital disorder involving the adenohypophysis, neurohypophysis and often the stalkPatients with pituitary hypoplasia survive with hormonal replacement but pituitary aplasia is incompatible with lifePituitary dwarfism due to deficiency of growth hormone is a common clinical presentation
18Hypoplastic Pituitary Gland A BFigure 4. Coronal (A) and sagittal (B) T1 images show small pituitary gland and stalk.
20Ectopic Neurohypophysis It is characterized by a “bright spot” along median eminence of hypothalamus or along stalk which may be tiny or absentAdenohypophysis and sella may be smallFrequently associated with growth hormone deficiency (pituitary dwarfism)Associated adenohypophysis dysfunction may be related to absent infundibulumAssociated midline CNS abnormalities: (septo-optic dysplasia, lobar holoprosencephaly, olfactory bulb anomalies)
21Ectopic Neurohypophysis A BFigure 6. Pre- (A) and post-Gd (B) sagittal T1 images show “bright spot” in tuber cinereum of the hypothalamus
22Ectopic Neurohypophysis with Thin Stalk Figure 7. Sagittal T1 image shows ectopic neurohypophysis (black arrow) in tuber cinereum and hypoplastic pituitary stalk (white arrow).
23Duplicated Pituitary Gland Rare congenital disorder due to duplication of primitive stomodeal structuresTwo sellae, lateral stalks and glands are presentMammillary bodies are fused with tuber cinereum, thickening of 3rd ventricle floor (hamartoma?)Basilar artery shows lack of longitudinal fusionAnterior 3rd ventricle may be duplicatedPossible association with CN I and II hypoplasiaPituitary-related symptoms are rareAssociations: craniofacial clefting, oral midline tumors, dysgenesis of corpus callosum, Dandy-Walker spectrum
24Duplicated Pituitary Gland A BFigure 8. Post–Gd coronal (A) and axial (B) T1 images show two stalks (arrows), pituitary glands and sellae.
25Tuber Cinereum Hamartoma It is a congenital malformation characterized by heterotopia of gray matter in the region of the mammillary bodies or tuber cinereumRound non-enhancing pedunculated or sessile mass, contiguous with tuber cinereum; isointense to gray matter on T1 and slightly T2 brightIsosexual precocious puberty due to LHRH and/or gelastic seizuresCommon associations: congenital facial/cerebral midline abnormalities, visceral anomalies, digital malformationsDifferential diagnosis: hypothalamic astrocytoma, hystiocytosis, germ cell tumor
26Tuber Cinereum Hamartoma A B CFigure 9. Post–Gd T1 (A), T2 (B) sagittal, and post-Gd T1 axial (C) images. A mass is seen between the infundibulum and mammillary bodies, hyperintense to gray matter on T2. The mass appears similar to the brain parenchyma on T1 and shows no enhancement (courtesy of Dr. A. Osborn).
27Tuber Cinereum Hamartoma A BFigure 10. Post–Gd sagittal T1 (A) and T2 (B) images show a large tuber cinereum hamartoma that is T1 isointense and T2 bright (courtesy of Dr. A. Osborn).
28Optic Infundibular Hypoplasia Disorder of midline prosencephalic development (6th weeks of life)Overlaps with septo-optic dysplasia but septum pellucidum is presentOptic chiasm/optic nerves are hypoplasticPituitary hypoplasia, thin stalk, ectopic neurohypophysis may be present
30Congenital Disorders Development of the Adenohypophysis
31Persistent Craniopharyngeal Canal A BFigure 12. Sagittal T1 (A) and coronal T1 (B) images. The craniopharyngeal canal is patent. The adenohypophysis is within the canal (arrow) and extends into the nasopharynx (arrowhead) (C/o of Dr. M. Michel)
32Persistent Craniopharyngeal Canal A BCut the faceFigure 13. Sagittal T1 MR (A) and axial CT (B) images. A: The adenohypophysis (arrow) is in a persistent craniopharyngeal canal. B: Shows persistence of a craniopharingeal canal (arrowhead) (C/o Dr. K. Marsot-Dupuch).
33Rathke’s Cleft CystNon-neoplastic cyst arising from remnants of squamous epithelium of Rathke’s cleftNon-enhancing non-calcified intra or supra-suprasellar cystVariable cyst content: mucous (T1 bright) serous (T1 dark) and possible blood products (T2 dark)
34Rathke’s Cleft CystA BFigure 14. Pre- (A) and post-Gd (B) T1 weighted images show an intrasellar mass (black arrow) that is bright compared to normal pituitary gland (white arrow). Location (middle 1/3 of gland) and signal intensity strongly suggest a Rathke’s cleft cyst
35Rathke’s Cleft CystFigure 15. Axial T2 image shows intrasellar mass with fluid level (arrow) a typical feature of Rathke’s cleft cyst; the differential diagnosis includes a hemorrhagic pituitary adenoma.
36CraniopharyngiomaBenign dysontogenetic epithelial tumor arising from cell remnants of Rathke’s pouchComplex mass, with inhomogeneous enhancement of solid componentsCalcifications: very commonT1 signal varies with cyst contentsBimodal age distribution (5-15 y; > 50)
37CraniopharyngiomaA BFigure 16. Sagittal post-Gd T1 (A) and coronal T2 (B) images show an enhancing suprasellar mass (arrows) with complex appearance.
38CraniopharyngiomaA BFigure 17. Coronal (A) and sagittal (B) post-Gd T1 images show a suprasellar cystic mass (white arrows). A solid enhancing nodule is noted (black arrow) and the rim also enhances (small white arrows).
39Pars Intermedia CystThese cysts arise in the pars intermedia of the adenohypophysis which is rudimentary in humansThey are usually less than 3 mm in diameterThey are located between the pars anterior and pars posterior
40Pars Intermedia Cyst A C B Figure 18. Sagittal pre- (A) and post-Gd (B) T1 images and (C) axial T2 image show nonenhancing cyst (arrows) between the pars anterior and pars posterior.
42DermoidIntracranial dermoids are ectodermal inclusion cysts that originate from midline inclusion of surface ectoderm during the 3rd-5th weeks of life at the time of closure of the neural tubeCommon intracranial locations: frontonasal, sellar and parasellar regions, posterior fossa and ventriclesDermoids are T1 bright due to presence of lipids and cholesterols and may rupture with spreading of fat droplets along the CSF containing spaces resulting in aseptic meningitis
43DermoidFigure 19. Sagittal T1 image shows a well-defined bright midline suprasellar mass (arrows).
44TeratomaTeratomas are composed of tissues from the three embryonic germ layersThe majority of teratomas are supratentorial in the region of the optic chiasm and in the pineal glandThey are midline tumors containing fat, soft tissue and calcificationsClassified as mature, immature and malignantOccasionally they present in newborns as holocranial tumors
45TeratomaA BFigure 20. Sagittal non-contrast T1 (A) and axial fat-suppressed T2 (B) images show a heterogeneous suprasellar mass (arrows) due to presence of calcifications and fat.
46ReferencesBarkovich, A., Pediatric Neuroimaging. 3rd edition ed. 2000, New York: Raven Press.Chen, C., D. David, and A. Hanieh, Morning glory syndrome and basal encephalocele. Childs Nerv Syst, 2004(20): pChong, B. and T. Newton, Hypothalamic and pituitary pathology. The Radiology Clinics of North America, (5): pDietrich, R., et al., Normal MR appearance of the pituitary gland in the first two years of life. AJNR, : pGray, H., Gray’s Anatomy. 37th edition ed. 1989, New York, Churchill Livingstone.Osborn, A., Diagnostic Imaging. Brain. 2004, Salt Lake City: Amirsys.Sadler, T., Susceptible periods during embryogenesis of the heart and endocrine glands. Environ Health Perspect., : pShroff, M., et al., Basilar artery duplication associated with pituitary duplication: a new finding. AJNR, 2003(24): p