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ESSENTIAL INFORMATION

Key Differential Diagnosis Issues
- Location is important
- Pituitary: Craniopharyngioma, Rathke cleft cyst, macroadenoma
- Stalk: Langerhans cell histiocytosis, lymphocytic hypophysitis, Rathke cleft cyst, craniopharyngioma, ectopic neurohypophysis
- Optic chiasm and hypothalamus: Astrocytomas
- Hypothalamus: Hamartoma, ectopic neurohypophysis
Helpful Clues for Common Diagnoses
- Craniopharyngioma - Proposed to arise from cellular elements related to Rathke pouch (craniopharyngeal duct) - Most common suprasellar mass in childhood; 2nd peak in adults (45-60 years) - Adamantinomatous ("90% tumor") - 90% Ca⁺⁺, 90% cystic - 90% enhance (rim ± nodule) - Papillary: Solid > cystic or solid/cystic; Ca⁺⁺ uncommon - Adults > > children
- Pilocytic Astrocytoma - 2nd most common suprasellar mass in children - Hypothalamus/optic pathways - Pilocytic > > pilomyxoid subtype - Typically T2 hyperintense with enhancement - Cysts less common than other CNS locations - WHO grade 1 tumor
- Germ Cell Tumor - Germinomatous = germinoma - Nongerminomatous = teratoma and miscellaneous - Germinoma - Stalk ± gland; lobular, homogeneous, enhancing mass - CT hyperdense - Ca⁺⁺ and cystic change uncommon - Can be only site, but look for pineal mass and leptomeningeal dissemination - Teratoma - Mature tumors with Ca⁺⁺, cysts, and fat - Immature tumors with heterogeneous enhancement and predominantly soft tissue - Nongerminomatous germ cell tumors - Choriocarcinoma, endodermal sinus tumor, embryonal cell carcinoma, mixed - Poor prognosis - Heterogeneously enhancing mass - Elevation of serum β-hCG &/or α-fetoprotein
- Langerhans Cell Histiocytosis - Thickened, enhancing, mass-like stalk - Look for beveled skull lesions, vertebra plana - Most common etiology of child with diabetes insipidus - Lack of posterior pituitary bright spot
Helpful Clues for Less Common Diagnoses
- Dilated 3rd Ventricle - Most common "cystic" suprasellar mass - 3rd ventricle enlarged secondary to hydrocephalus - Inferior displacement of suprasellar structures
- Pituitary Macroadenoma - Rare in children, more common in teenagers and adults - Suprasellar extension of macroadenoma - Gland and mass are inseparable - Cystic, hemorrhagic changes less common
- Tuber Cinereum Hamartoma - Clinical presentation helpful (gelastic seizures; male with precocious puberty) - Can be "collar button" or "sessile" - Between infundibulum (anteriorly), mammillary bodies (posteriorly) - Signal intensity like gray matter, no enhancement - Mild T2 hyperintensity may be seen
- Leptomeningeal Metastases - Typically from primary CNS high-grade neoplasm - Medulloblastoma, germinoma
- Arachnoid Cyst - Elevates, displaces 3rd ventricle - Follows CSF on all sequences
- Rathke Cleft Cyst - Similar embryologic origin as craniopharyngioma - Variable T1 hyperintensity and T2 hypointensity in cyst - Look for intracystic nodule from protein concretions - Rim enhancement rare; contents do not enhance - Pituitary gland/infundibulum displaced by mass
- Basilar Meningitis - Most commonly bacterial but may be fungal or mycobacterial - Leptomeningeal enhancement - Look for basal ganglia infarcts from arteritis - Tuberculoma - TB meningitis > tuberculoma in suprasellar cistern - Focal mass with ring enhancement common - If caseating, mass is hypointense on T2WI - If noncaseating, mass is generally hyperintense on T2WI
- Neurocysticercosis - Suprasellar cistern, sylvian fissures common sites - Variable size cysts, enhancement - Reactive meningeal changes may show intense enhancement
- Dermoid Cyst - Fat containing: MR fat suppression or negative HU - Rupture = leptomeningeal fat and chemical meningitis - Surface ectoderm inclusion with neural tube closure
- Lipoma - Fatty mass stuck on hypothalamus - Use fat-saturated T1WI
Helpful Clues for Rare Diagnoses
- Pilocytic Astrocytoma, Pilomyxoid Subtype - Rare, more aggressive than pilocytic astrocytoma (PA) - Infant/young child with bulky, H-shaped suprasellar mass - Often hemorrhages (less common in PA) - More likely than PA to have leptomeningeal dissemination
- Ectopic Neurohypophysis - Failure of neurohypophysis descent from hypothalamus - T1-hyperintense lesion from hypothalamus through stalk - Associated with septo-optic dysplasia
- Lymphocytic Hypophysitis - Thick, nontapering stalk ± pituitary mass - Diabetes insipidus common - Often occurs in peripartum females; rare in children - May be autoimmune, inflammatory, granulomatous (sarcoid, Langerhans cell histiocytosis, infectious, etc.), IgG4 related or drug related (cancer immunotherapy)
- Epidermoid Cyst - Lobulated, irregular cyst not following CSF - Incomplete FLAIR suppression; decreased diffusion - Surface ectoderm inclusion with neural tube closure

References

Selected References

Images

Selected Images

Craniopharyngioma Sagittal NECT shows a heterogeneous mass with coarse Ca⁺⁺ . Adamantinomatous craniopharyngiomas are WHO grade 1.

Craniopharyngioma Sagittal T1 C+ MR in the same patient shows the sellar and suprasellar mass has solid, enhancing components and large cysts with intrinsic T1 shortening . Craniopharyngiomas are the most common suprasellar mass in children and should be considered when a tumor has cysts, enhancement, and Ca⁺⁺.

Pilocytic Astrocytoma Axial T2 MR shows a heterogeneous suprasellar mass with solid and cystic components . This WHO grade 1 tumor causes mass effect on the midbrain, R > L .

Pilocytic Astrocytoma Sagittal T1 C+ MR in the same patient shows an enhancing, solid and cystic mass in the suprasellar cistern with involvement of the sella turcica. Note the flattened pituitary gland , which is separate from the mass. This tumor likely arises from the optic chiasm &/or the hypothalamus.

Pilocytic Astrocytoma Axial b = 1000 DWI trace MR in the same patient shows the solid portions of the mass are predominantly isointense compared to normal brain. These features support the diagnosis of a low-grade neoplasm, pilocytic astrocytoma, WHO grade 1, in this case.

Germinoma Sagittal T1 C+ MR shows a heterogeneously enhancing mass involving the pituitary gland and stalk . There is heterogeneous enlargement of the pineal gland , which is also involved by germinoma. Germinomas are classically CT hyperdense.

Teratoma Sagittal T1 MR shows a large, heterogeneous mass, which appears to arise from the suprasellar cistern and cause severe hydrocephalus. Note the T1-hyperintense area consistent with fat . Also note the T1-bright posterior pituitary gland .

Teratoma Coronal T1 C+ MR in the same infant shows heterogeneous enhancement of the mass. This was a congenital tumor. With the fat products and central location, this is consistent with a teratoma. Mature teratomas are more common than immature teratomas.

Langerhans Cell Histiocytosis Sagittal T1 C+ MR shows enhancing thickening of the infundibulum . This child presented with diabetes insipidus and had a bone lesion consistent with Langerhans cell histiocytosis (LCH). LCH is the most common finding in a child with diabetes insipidus.

Dilated 3rd Ventricle Sagittal T1 MR shows enlargement of the 3rd ventricle from obstructive hydrocephalus. There is anterior displacement of the lamina terminalis and depression of the hypothalamus and suprasellar structures .

Pituitary Macroadenoma Coronal T1 C+ MR shows a large sellar and suprasellar mass related to a pituitary macroadenoma. There is extension of the mass over the cavernous carotid artery beyond the medial tangential line , consistent with grade 1 Knosp classification for risk of cavernous sinus invasion.

Tuber Cinereum Hamartoma Sagittal T2 MR shows a hypothalamic mass centered on the tuber cinereum . The mass follows brain parenchyma on all sequences and does not enhance, consistent with a hypothalamic hamartoma.

Leptomeningeal Metastases Axial T1 C+ MR shows nodular and leptomeningeal enhancement in the suprasellar cistern . In addition, there is abnormal enhancement in the 4th ventricle . This was a disseminated diffuse midline glioma of the brainstem, WHO grade 4.

Arachnoid Cyst Sagittal T1 MR shows cystic dilatation of the suprasellar cistern with superior displacement of the tuber cinereum . There is stretching of the stalk with incidental T1 hyperintensity from an ectopic posterior pituitary gland .

Rathke Cleft Cyst Sagittal T1 C+ MR shows a sellar and suprasellar cystic lesion with suprasellar extension and mass effect.

Rathke Cleft Cyst Coronal T2 MR shows the cystic sellar/suprasellar mass has a faint T2-hypointense nodule . This likely represents focal proteinaceous concretion and is consistent with Rathke cleft cyst. Note the mass effect on the chiasm . Rathke cleft cysts have the same embryologic origin as craniopharyngioma and likely represent surface ectodermal rests during anterior pituitary migration.

Basilar Meningitis Coronal T1 C+ FS MR shows diffuse abnormal enhancement throughout the suprasellar cistern with thickening of the stalk and extension to the left temporal lobe and right basal ganglia.

Basilar Meningitis Axial DWI trace MR shows multiple areas of diffusion hyperintensity. There is pus in the anterior 3rd ventricle and less conspicuous pus in the occipital horn . Diffusion restriction in the basal ganglia and thalamus may represent cerebritis; however, there is also likely arteritis with multiple areas of infarct .

Tuberculoma Axial T1 C+ MR shows abnormal enhancement in the suprasellar cistern, interpeduncular cistern , and left ambient cistern . This child has a known history of TB.

Neurocysticercosis Coronal T1 C+ MR shows abnormal enhancement in the right suprasellar cistern and right sylvian fissure in this patient with known neurocysticercosis. Leptomeningeal disease occurs when larvae invade the subarachnoid space and cause extensive inflammation and arachnoiditis.

Dermoid Cyst Axial T1 MR shows a heterogeneous, T1-hyperintense mass in the right suprasellar cistern . Note the T1 punctate hyperintensities in the suprasellar cistern, interpeduncular cistern, and in the anterior cranial fossa from fatty elements due to dermoid cyst rupture. This patient is at risk for chemical meningitis.

Dermoid Cyst Coronal T1 C+ FS MR shows signal loss of the right suprasellar mass , consistent with fat. Dermoid cysts arise from surface ectoderm rests during neural tube closure.

Lipoma Sagittal T1 MR shows a intrinsically bright T1 lesion in the suprasellar cistern along the stalk . Note the normal location of the posterior pituitary , which makes ectopic posterior pituitary unlikely. Fat saturation images confirmed a lipoma.

Pilocytic Astrocytoma, Pilomyxoid Subtype Coronal T1 C+ MR shows an intensely enhancing mass in the suprasellar cistern associated with a large cyst displacing the left frontal and temporal lobes. In an infant, pilomyxoid astrocytoma should be considered, an aggressive variant of pilocytic astrocytoma.

Ectopic Neurohypophysis Sagittal T1 MR shows a hyperintense nodule in the hypothalamus . There is hypoplastic pituitary gland without visualization of the normal posterior pituitary bright spot . This is consistent with ectopic neurohypophysis. Note the absence of the infundibulum .

Lymphocytic Hypophysitis Sagittal T1 C+ MR shows thickening of the stalk with extension into the pituitary gland . There is loss of the normal posterior pituitary bright spot on noncontrast T1 MR (not shown).

Epidermoid Cyst Axial FLAIR MR shows heterogeneous nonsuppression of a cystic mass in the suprasellar cistern. This showed T2 hyperintensity and no contrast enhancement.

Epidermoid Cyst Axial b = 1000 DWI MR shows decreased diffusion of the cystic mass, confirming the diagnosis of epidermoid cyst. Epidermoid cysts and dermoid cysts derive from surface ectoderm rests during neural tube closure. Dermoid cysts differ from epidermoid cysts due to inclusion of epidermal appendages, which can secrete fatty sebum.

Additional Images

Pituitary Macroadenoma Sagittal T1 C+ FS MR shows a pituitary macroadenoma . The pituitary gland cannot be seen separate from the mass. The mass is the gland, which is diffusely enlarged by the tumor.

Craniopharyngioma Sagittal T1 MR shows a craniopharyngioma with variable T1 shortening within the multiloculated cystic components. The pituitary gland is clearly distinct from the mass.

Pilocytic Astrocytoma Sagittal T1 C+ MR shows a large pilocytic astrocytoma, seen here as a lobulated, inhomogeneously enhancing suprasellar mass . The pituitary is clearly separate from the mass.

Dilated 3rd Ventricle Sagittal T1 C+ MR shows obstructive hydrocephalus with a dilated 3rd ventricle . The large anterior recesses compress and displace the infundibular stalk and hypothalamus inferiorly.

Arachnoid Cyst Sagittal T1 MR shows a classic suprasellar arachnoid cyst. Note that the CSF-like suprasellar mass elevates the 3rd ventricle and displaces the infundibular stalk anteriorly .

Neurocysticercosis Sagittal T1 MR in a patient with known neurocysticercosis shows a markedly thickened infundibulum as well as multiple supra- and intrasellar cysts . Basal cistern lesions are common in neurocysticercosis.

Rathke Cleft Cyst Sagittal T1 MR shows a typical Rathke cleft cyst. Note that the well-delineated, hyperintense suprasellar mass is clearly distinct from the pituitary gland below.

Langerhans Cell Histiocytosis Sagittal T1 C+ MR in a child with known histiocytosis and diabetes insipidus shows a strongly enhancing mass involving the infundibular stalk and hypothalamus .

Germ Cell Tumor Sagittal T1 C+ MR shows a germinoma with sellar and suprasellar involvement. The infundibular stalk is markedly thickened, while the pineal gland is normal.

Dermoid Cyst Sagittal T1 C+ MR shows a ruptured dermoid cyst with a large supra-/parasellar component. Note multiple high signal intensity droplets scattered throughout the subarachnoid space.

Lipoma Sagittal T1 MR shows a hypothalamic lipoma , seen here as a lobulated, hyperintense mass above and behind the sella. This was an incidental finding in an asymptomatic patient.

Lymphocytic Hypophysitis Sagittal T1 C+ FS MR in a 19-year-old pregnant woman shows a uniformly enhancing sellar/suprasellar mass . Note reactive dural thickening . Lymphocytic hypophysitis was found at surgery.

Tuber Cinereum Hamartoma Sagittal T1 MR shows a classic tuber cinereum hamartoma . The hamartoma looks like a "collar button" of gray matter interposed between the infundibulum and mammillary bodies.

Epidermoid Cyst Axial T1 MR shows an epidermoid cyst . The lobulated, CSF-like mass extends into the suprasellar and quadrigeminal cisterns.

Pilocytic Astrocytoma, Pilomyxoid Subtype Coronal T2 MR in a 21-year-old man with sudden headache and visual problems shows a hemorrhagic suprasellar mass . Initial diagnosis was pilocytic astrocytoma. The final diagnosis was pilomyxoid astrocytoma.

Ectopic Neurohypophysis Sagittal T1 MR shows posterior pituitary ectopia, seen here as a hyperintense focus along the upper infundibulum. Note a small pituitary gland with an absent bright spot.

Tuberculoma Axial CECT shows a tuberculoma in the suprasellar cistern, seen here as a ring-enhancing mass. Note accompanying findings of TB meningitis . (Courtesy S. Candy, MD.)

Langerhans Cell Histiocytosis Sagittal T1 C+ MR in a child with known histiocytosis and diabetes insipidus shows an enhancing mass involving the hypothalamus and infundibular stalk .

Tuber Cinereum Hamartoma Sagittal T1 MR shows a variant case of tuber cinereum hamartoma with a large, lobulated suprasellar mass extending posteroinferiorly behind the clivus, displacing the brainstem backwards.

Dermoid Cyst Sagittal T1 MR shows an irregular mass with predominantly T1-hyperintense signal involving the pituitary, stalk, and hypothalamus. Dermoid cysts are an inclusion of the surface ectoderm during neural tube closure and classically occur midline.

Pituitary Macroadenoma Sagittal T1 C+ FS MR shows an enhancing mass expanding the sella. The infundibulum is intact above the mass , suggesting the mass is the pituitary gland. Macroadenomas are not typically seen in young children but may be seen in teenagers and adults.

Dermoid Cyst Coronal T2 FS MR shows signal loss of the T1-hyperintense sellar/suprasellar mass , consistent with fatty dermal elements from a dermoid cyst. Leptomeningeal fat suggests cyst rupture.

Epidermoid Cyst Axial DWI b = 1000 MR shows decreased diffusion in a heterogeneous, cystic mass arising from the suprasellar cistern, consistent with an epidermoid cyst. Like dermoid cysts, epidermoid cysts arise from surface ectoderm rests included during neural tube closure.

Epidermoid Cyst Sagittal T1 C+ MR shows a nonenhancing cystic mass in the suprasellar cistern effacing the pituitary gland. There is mild rim enhancement . Epidermoid cysts have incomplete FLAIR suppression but are otherwise similar to CSF signal.

Lymphocytic Hypophysitis Sagittal T1 C+ FS MR shows an enhancing mass in the pituitary stalk. This is a child with lymphocytic hypophysitis, a rare finding in children. Enhancing lesions of the stalk in a child are most likely to be Langerhans cell histiocytosis.

Ectopic Neurohypophysis Axial T1 MR shows a T1-hyperintense nodule along the pituitary stalk. There is absence of the normal T1 posterior pituitary bright signal, and this mass is consistent with an ectopic posterior pituitary. An ectopic neurohypophysis can be located along the hypothalamus or stalk.

Pilocytic Astrocytoma, Pilomyxoid Subtype Axial T1 C+ MR shows a bilobed mass with the largest portion in the suprasellar cistern. Pilomyxoid astrocytomas, despite being WHO grade 2, can demonstrate leptomeningeal dissemination, and the entire neuraxis should be imaged.

Pilocytic Astrocytoma, Pilomyxoid Subtype Axial T2 FS MR shows a bilobed mass in the suprasellar cistern, which is predominantly T2 hyperintense with central T2 hypointensity from blood products. Hemorrhage is more common in pilomyxoid astrocytomas rather than pilocytic astrocytomas.

Neurocysticercosis Coronal T1 C+ FS MR shows multiple cysts with rim enhancement in the suprasellar cistern and left sylvian fissure from racemose neurocysticercosis. In addition, there is nodular enhancement in the left basal ganglia from a cyst in the granular nodular phase.

Neurocysticercosis Axial T2 FS MR shows multiple cysts in the suprasellar cistern with extension into the interhemispheric fissure and left sylvian fissure. Racemose neurocysticercosis typically presents as grape-like cysts in the cisterns.

Tuberculoma Axial T2 FS MR shows an isointense nodule in the suprasellar cistern and interpeduncular cistern. There is central hypointensity within the nodular mass from Ca⁺⁺. There is also adjacent midbrain edema . This is consistent with a caseating tuberculous granuloma.

Tuberculoma Sagittal T1 C+ FS MR shows an enhancing nodule in the suprasellar cistern and interpeduncular cistern in a child with history of CNS TB. A 2nd tuberculoma can be seen at the pontomedullary junction .

Basilar Meningitis Axial T1 C+ MR shows diffuse irregular leptomeningeal enhancement filling the suprasellar cistern and extending into the sylvian fissures, interpeduncular cistern, and ambient cisterns. This was a pyogenic basilar meningitis.

Basilar Meningitis Axial DWI b = 1000 MR shows a focus of decreased diffusion within the right pons from infarct of a pontine perforator. This child had basilar meningitis and arteritis of an end artery supplying the pons. Classically, basal ganglia infarcts from lenticulostriate arteritis are seen.

Rathke Cleft Cyst Coronal T1 C+ FS MR shows a rim-enhancing cystic mass in the suprasellar cistern involving the pituitary, stalk, and extending through the hypothalamus. This was a Rathke cleft cyst at resection. Craniopharyngioma typically will have larger, solid enhancing elements.

Arachnoid Cyst Coronal T1 C+ FS MR shows an arachnoid cyst involving the suprasellar cistern. There is rightward displacement of the pituitary stalk and extension into the left temporal horn with outward displacement and thinning of the temporal lobe .

Leptomeningeal Metastases Sagittal T1 C+ MR in a child with disseminated neuroblastoma shows enhancement along the lamina terminalis and hypothalamus in addition to diffuse leptomeningeal enhancement, which also involves the cerebellum .

Leptomeningeal Metastases Coronal T1 C+ FS MR shows diffuse leptomeningeal enhancement predominantly in the suprasellar cistern, sylvian fissures, and interhemispheric fissure. This child had a history of neuroblastoma.

Tuber Cinereum Hamartoma Sagittal T1 C+ FS shows a nonenhancing mass in the suprasellar cistern pedunculated from the tuber cinereum of the hypothalamus. Tuber cinereum hamartomas can be pedunculated or sessile and generally follow gray matter in intensity.

Tuber Cinereum Hamartoma Coronal T2 MR shows a sessile mass centered in the hypothalamus, which follows gray matter in intensity. Tuber cinereum hamartomas classically present with gelastic seizures and precocious puberty.

Dilated 3rd Ventricle Sagittal T1 C+ MR shows a tectal mass causing obstructive hydrocephalus. There is downward displacement of the lamina terminalis and hypothalamus , effacing the infundibulum and suprasellar cistern.

Langerhans Cell Histiocytosis Coronal T1 C+ FS MR shows abnormal thickening of the infundibulum and pituitary gland. In a child with diabetes insipidus, Langerhans cell histiocytosis should be considered. Further search for bony lesions with beveled edges should be performed.

Pilocytic Astrocytoma Axial T1 C+ MR shows the enhancing mass in the suprasellar cistern has a central nonenhancing structure consistent with an enlarged optic chiasm . This tumor was a pilocytic astrocytoma at biopsy.

Germinoma Sagittal T1 C+ MR shows lobular enhancing masses in both the pineal region and suprasellar cistern. The pineal region mass has a central hypointensity consistent with engulfed pineal Ca⁺⁺, typical for germ cell tumor. Germinomas can disseminate, & these 2 locations are most common.

Nongerminomatous Germ Cell Tumors Sagittal T1 C+ MR shows a lobular suprasellar mass involving the stalk and hypothalamus with extension into the 3rd ventricle . This was a mixed germ cell tumor at resection.

Pilocytic Astrocytoma Axial T2 MR shows a predominantly T2-hyperintense mass in the suprasellar cistern with a shape similar to the optic chiasm. Pilocytic astrocytomas are the 2nd most common suprasellar mass in children.

Craniopharyngioma Coronal T1 C+ FS MR shows a heterogeneous mass with enhancing solid elements and cystic change involving the hypothalamus and pituitary stalk in the suprasellar cistern. Adamantinomatous craniopharyngiomas are the most common suprasellar mass in children.

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ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Helpful Clues for Common Diagnoses

Helpful Clues for Less Common Diagnoses

Helpful Clues for Rare Diagnoses