Third Eye Blind? Pearls for Differentiating Pineal Lesion

ASNR 2015

eEdE-68; SN: 956 

Ammar Chaudhry MD; Robert Shroyer MD; Alexander Filatov MD; Robert Peyster MD; Lev Bangiyev DO

Disclosures

• None

What is the Pineal Gland?

• Functions:1. Neuroendocrine: melatonin synthesis

- Regulated by sympathetic input

2. Biological rhythms (e.g. circadian, puberty)• Histologically: pineocytes (95%) and astrocytes

(5%) separated by fibrovascular stroma• No blood brain barrier enhances

Why is the Pineal the “Third Eye”?

• Similar Embryologic Development– Evaginates from caudal aspect of third ventricular

roof during 7th week of gestation– Similar to the optic vesicles

• Retains photosensitivity in lower vertebrates– No longer photosensitive in mammals

• Humans: accessory optic pathway– Retinohypothalamic tract reticulo-activating

system autonomic function

Quadreminal Cistern Anatomy

http://mystatdx.com

Pineal Region Anatomy on T2 MRI

http://mystatdx.com

Pineal Region Mass DDX• Germ Cell Tumors (60%)

– Germinoma (40%)– Teratoma (15%)– Malignant GCT NOS

• Pineal Parenchymal Tumors (15%)– Pineocytoma (7%) – WHO Grade I– Pineal Parenchymal Tumor of

Intermediate Differentiation (PPTID) (3%)– Pineoblastoma (6%) – WHO Grade IV– Trilateral Retinoblastoma

• Neoplasms of Adjacent Tissues– Astrocytoma (e.g. Tectal Plate Glioma)– Meningioma– Lymphoma

• Papillary Tumor of the Pineal Region

• Non-neoplastic– Pineal Cyst– Lipoma– Arachnoid Cyst – Dermoid /Epidermoid– Vein of Galen

Malformation– Neurocysticercosis– Neurosarcoid– Medial Atrial

Diverticulum of Lateral Ventricle

– Cavum Velum Interpositum

Case #1: 11 y/o girl with migraine HA

T1WI T2WI T1 C+

Pineal Cyst

Case #1: Incidental finding

• Typically clinically silent– Rarely symptomatic

when large of hemorrhage (5%)

• Incidence among women between 21-30 years higher than any other group; F:M = 3:1

• Histology: Non-neoplastic glial-lined protienaceous cyst

Pineal Cyst Pearls• CT:

– Isodense to slightly hyperdense c/w CSF– Mural calcification (25%), – Multicystic/septated (20-25%)

• MRI: Incidental finding in 1-5% of MRIs– T1: Isointense (40%) to slightly hyperintense

(60%) c/w CSF– T2: Isointense to slightly hyperintense c/w CSF– FLAIR: Does not fully suppress– DWI: Typically no restriction– T1 C+: 90% enhance

• Usually thin rim; nodular/irregular less common• May demonstrate progressive fill-in

• DDx: Pineocytoma, Epidermoid cyst, Arachnoid cyst

ADC

CT C-

DWISag T1WI C+

Sag T2WI

Case #2: 12 y/o boy with emesis

• Symptomatic at diagnosis: Parinaud syndrome, headache, hydrocephalus– Elevated placental alkaline

phosphatase (PLAP)– ± Elevated β-HCG

• Incidence Highest in young male Asian patients– 90% < 20 y/o (peak: 10-12)– M:F = 10:1 in pineal region

• Histology: Similar to ovarian dysgerminoma and testicular seminoma

Germinoma

Germinoma Pearls• 80-90% in midline by 3rd ventricle

– Pineal region (50-65%)– Suprasellar (25-35%)– Basal ganglia/thalami (10%)

• CT:– “Engulfs” pineal calcification – High cellularity hyperdense c/w grey matter– When large become cystic, necrotic, and/or

hemorrhagic• MR:

– High cellularity T2 hypointense c/w gray matter– DWI: restricted diffusion– T1 C+: Avid homogeneous enhancement– Look for leptomeningeal seeding and brain

invasion– Image entire spine before surgery

• DDx: Non-germinomatous GCTs, pineoblastoma

9 y/o boy with four-months of HA and Pineal Germinoma

NCCT T2 T1 C+

Case #3: 10 y/o boy with headache

Ax T1WI Post

Ax CT C-

Ax T2WI Sag T1WI Pre

Sag T1WI Post

• Teratoma• Congenital midline mass

– Large mass → Macrocephaly

– Pineal origin → Perinaud’s

– Increased serum carcinoembryonic antigen (CEA)

– May rupture and cause chemical meningitis

• Most common in male Asians

• Histology: contains elements of 3 germ layers (ectoderm, mesoderm, endoderm)

Teratoma Pearls• Suprasellar or pineal in origin

– Origin indeterminate in ~50%• CT:

– Heterogeneous mixture of calcification, soft tissue, multilocular cysts, and fat

• MRI:– High cellularity T2 hypointense c/w gray

matter– DWI: Restricted diffusion in solid components – T1 C+: Solid component enhances

• WHO: mature (cystic), immature, malignant

• DDx: craniopharyngioma, dermoid, germinomatous GCT, pineoblastoma

20 year old male p/w HA, double vision, and N/V x 2 months; slightly elevated HCG and AFP

• Choriocarcinoma: β-hCG hemorrhage (T1 can mimic fat)• Endodermal sinus tumor: α-fetoprotein (AFP)• Embryonal cell carcinoma: β-hCG and AFP• Difficult to differentiate from other CNS GCTs on imaging• Visual/endocrine symptoms, Parinaud syndrome• Signs of hypothalamic/pituitary dysfunction• +/- hydrocephalus• Female predominance in suprasellar cases• Locally invasive with metastatic potential• Malignant GCTs often histologically mixed

– May exist with both germinomatous, other nongerminomatous GCTs

– Prognosis correlated with most malignant component• Prognosis

– Median survival < 2 years– 5-year survival rate < 25%

• Surgical resection → chemotherapy → neuraxis radiation• Combination of pre- and post-irradiation chemotherapy:

Improved survival

Malignant Germ Cell Tumor (GCT)

Ax CT C-

Ax T1WI Post Ax T2WI FS

Sag T1 Pre

Malignant GCT• Heterogeneous midline lesions composed of undifferentiated cells

(serum/CSF markers)– Soft tissue ± hemorrhage, cysts, fat– Pineal and suprasellar most common

• Seen in late adolescents (around puberty): peak = 10-15 y/o– M:F = 14:1 for purely pineal lesions– More common in Asians

• Includes: embryonal carcinoma, yolk sac tumor, choriocarcinoma, teratoma with malignant transformation, and mixed GCT– Can have variable leptomeningeal spread– Heterogeneous enhancement with reduced diffusion in solid

components (cellularity)• DDx: dermoid, other GCT, pineoblastoma

Sag FLAIR

Ax FLAIR Ax T2WI Ax T1WI C+

Sag T1WIC+

Ax CT C-

Case #4: 21 y/o male with worsening headaches x 1 year and new nausea, blurry vision

Pineocytoma• Stable or slow growing

– Symptoms: HA, Parinaud’s, increased ICP, ataxia, hydrocephalus, mental status changes

• Mean age at diagnosis: 35 years– Peak incidence: 10-20

years– No gender predilection– Germ cell markers

negative• Histology: Composed of

small, uniform, mature cells that resemble pineocytes

Pineocytoma Pearls• WHO grade I

– 100% 5-year survival• CT

– Well circumscribed, typically <3 cm– Isodense to hypodense– Peripheral "exploded" pineal calcifications– Can be cystic with occasional hemorrhage

• MRI– T1W: Isointense to hypointense c/w gray

matter– T2W/FLAIR: Hyperintense c/w gray matter– T1C+: solid, rim, nodular

• DDx: Pineal cyst, PPTID, pineoblastoma, GCT

DWI

Sag T1WI C+Sag T1WI

Ax T2WI ADCAx CT C-

Case #5: 32 y/o male with severe headache and gait instability

PPTID• Intermediate in

malignancy between pineocytoma and pineoblastoma

• Primary adult parenchymal neoplasm

• Histology: Dysplastic, atypical pineocytes with variable number of mitotic figures

Pineal Parenchymal Tumor of Intermediate Differentiation

• WHO grade II or III, depending on number of mitotic figures– Infiltrate adjacent structures (e.g., ventricles, tectum, thalamus)– Local recurrence common– Leptomeningeal dissemination rare

• CT– Hyperdense due to increased cellularity– “Engulfs” pineal calcification

• MR– T1: Mixed isointense and hypointense c/w gray matter– T2/FLAIR: Isointense c/w gray matter; small cystic foci– DWI: Not diffusion restricting– T1C+: Strong, heterogeneous enhancement

• DDx: GCT, pineocytoma, pineoblastoma

Case #6: 3 y/o boy with lethargy and emesis for 1 ½ months

DWI

Sag T1WI Pre

Ax T1WI PostAx T2WI

ADC

• Aggressive symptomatic mass– Hydrocephalus– Headache, nausea, vomiting,

lethargy– Papilledema, abducens nerve

palsy– Parinaud syndrome, ataxia

• Mean age at diagnosis: 3 years– F:M = 2:1– Germ cell markers negative

• Histology: Highly malignant primitive neuroectodermal tumor (PNET) derived from embryonic precursors of pinealocytes

Pineoblastoma

Pineoblastoma• WHO grade IV

– Median survival 16-25 months – Frequent brain invasion

• Corpus callosum, thalamus, midbrain, vermis

• CT– Large, heterogeneous mass with poorly defined margins– solid component hyperdense– peripheral “exploded”calcifications

• MRI (heterogeneous with necrosis/hemorrhage)– T1W: isointense to hypointense c/w gray matter– T2W: isointense to hypointense c/w gray matter– DWI: Restricted– T1W+: variable heterogeneous enhancement

• Frequent (15-45%) leptomeningeal seeding– Image entire spine preoperatively

• DDx: GCT, pineocytoma, astrocytoma

Case #7: 4 y/o girl with congenital bilateral retinoblastomas p/w severe HA and vomiting x 4d

Ax T1WI PostAx T2WI Sag T1WI Post

Ax CT C- Ax CT C+

• Combination of bilateral retinoblastoma and midline intracranial neuroblastic mass– 80% pineal, 20% suprasellar– Represents 5-15% of familial lesions;

rarely sporadic cases– Quadrilateral (tetralateral) = bilateral

Rb plus pineal AND suprasellar masses

• 90-95% diagnosed by age 5 years– Sporadic (nongermline): 60%– Inherited (germline): 40%– Prognosis <24 months

• Histology: Primitive neuroectodermal tumor (PNET)

“Trilateral” Retinoblastoma

• Circumscribed (pilocytic) or diffusely infiltrating

• MRI:– T1: isointense– T2/FLAIR:

hyperintense – T1C+: variable

enhancement• Histology: Typically

low grade

Case #8: 28 y/o male with long standing stable pineal mass

Sag T1WI Post Ax FLAIR Ax CT C-

Tectal Astrocytoma

Sag T1WI Post

Case #9: 51 y/o woman presented after an episode of severe headache and memory loss

Papillary Tumor of the Pineal Region• Primary tumor of adults• MRI:

– T1W: can be heterogeneously hyperintense– T2W/FLAIR: heterogeneously isointense to hyperintense; can have cystic regions– T1W+: moderate heterogeneous enhancement

• Histology: specialized ependymocytes of the subcommissural organ or ependymal cells of pineal recess

Sag T1WI Post AX T1WI Pre Ax FLAIR Ax T2WI

Case #10: 43 y/o female with vertigo

• Typically asymptomatic • Congenital malformation of meninx primitive

– Associated anomaly of corpus callosum, cephalocele, or spinal dysraphism in 1/3 cases• Lobulated midline extra-axial mass with fat attenuation/intensity across modalities/sequences

– No enhancement– Variable calcification– May encase vessels and cranial nerves resection difficult

• Histology: Mature non-neoplastic adipose tissue

Pineal Lipoma Sag T1WI FS Post AX T1WI Pre Ax T2WI Sag T1WI Pre

12 year old girl p/w HA, blurry vision, diplopia, N/V x 4 days

Arachnoid Cyst• Intra-arachnoid CSF-filled cyst• Exerts mass effect• No communication with ventricular

system• Any age; M:F = 3-5:1• Incidental finding on 2% of scans

CT: isodense c/w CSF (unless hemorrhage)MR

T1W/T2W/FLAIR: isointense c/w CSF (unless hemorrhage)T1W+: no enhancementDWI: no reduction

DDx: Epidermoid cyst

Ax FLAIR Sag T2WI Ax CT C- ADC

19 year old male with progressive HA and ataxia x 1month

• Benign squamous epithelial cyst with dermal elements• Midline fat-containing unilocular cystic lesion• Suprasellar most common location• Rupture can cause chemical meningitis– Subarachnoid lipid droplets– Fat-fluid level in ventricles• CT

– hypodensity (lipid)– fat-fluid level in cyst • MRI

– T1W: hyperintense (lipid)– T2W: heterogeneous– signal drop with fat suppression

• DDx: epidermoid cyst, craniopharyngioma, teratoma, lipoma

Dermoid Cyst Ax T2WI Ax CT C- Sag T1WI Pre

40 year old male presents following seizure

• Ectodermal inclusions • Intradural (90%), primarily in basal cisterns• Extradural (10%): skull and spine• Lobulated cauliflower-like mass with “fronds”

– Insinuates cisterns and encases neurovascular structures

• Chemical meningitis and CSF seeding with rupture• CT

– > 95% hypodense (CSF-like); rare "dense" variant

• MRI– T1W: typically slightly hyperintense c/w CSF (75%)– T2W: isointense (65%) to slightly hyperintense (35%) c/w

CSF– FLAIR: usually incomplete nulling– T1W+: minimal rim enhancement (25%)– DWI: markedly reduced

• DDx: arachnoid cyst, neurocysticercosis, cystic neoplasm, dermoid cyst

Epidermoid Cyst

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