This document discusses masses that can occur in the pineal region. It describes benign cysts as common incidental findings, seen more often in younger women. Germ cell tumors are another common type and include germinomas, teratomas and others. Imaging can help differentiate these. Rarer parenchymal cell tumors include pineocytomas and pineoblastomas. Extrinsic masses such as gliomas, vein of Galen aneurysms, meningiomas and lipomas are also discussed along with their characteristic imaging features.

1. Pineal Region Masses

3. A-Genu of the
Corpus Callosum
B-Anterior Horn of
the Lateral Ventricle
C-Internal Capsule
D-Thalamus
E-Pineal Gland
F-Choroid Plexus
G-Straight Sinus

5. Axial view
1-Pineal gland
2-Habenula
3-3rd ventricle
4-Pulvinar
5-Lateral ventricle

6. Coronal View
1 Pineal gland
2Lateral ventricle
3-Corpus callosum
4-Fornix
5 Thalamus
6Middle cerebellar
peduncle

7. Sagittal View
1Posterior
commissure
2Cerebral aqueduct
(of Sylvius)
3 Tectum
4Fourth ventricle
5-Cerebellum
6Quadrigeminal
cistern
7 Pineal gland
8Splenium , corpus
callosum
9 Third ventricle

8. Pineal Mass :
1 Benign Cyst
2 Germ Cell Tumors
3Parenchymal Cell Tumors
4 4-Metastases

9. 1-Benign Cyst :
a) Incidence
b) Radiographic Features
c) Differential Diagnosis

10. a) Incidence :
20-30 years of age, more in women
-Simple cystic structure within the gland
measuring < 1.5 cm
-Unlikely to be significant when no mass effect
and when there are no relevant symptoms

12. b) Radiographic Features :
*CT :
-Well circumscribed fluid density lesions with
thin rim calcification seen in 25%
-Some peripheral enhancement is also often
seen
-The internal cerebral veins are elevated and
splayed by the cyst

14. *MRI :
-Slightly higher signal than CSF on all sequences
-A common incidental finding on MRI studies
*T1 :
-Typically iso to low signal compared to brain
parenchyma
-55 to 60% are somewhat hyperintense when
compared to CSF
-Generally homogenous signal

19. *T1+CApproximately 60% of lesions enhance
-Enhancement is usually thin (< 2mm) and
confined to the rim (either complete or
incomplete)
-It is important to note that if post contrast
imaging is delayed (60 - 90min), gadolinium
may diffuse into the cyst fluid and may lead
to the mass appearing solid
:
-

22. c) Differential Diagnosis :
-A differential consideration is Pineocytoma
which would shows internal enhancement and
may have cystic component, however a truly
cystic Pineocytoma is considered very rare

23. 2-Germ Cell Tumors :
a) Germinoma (most common)
b) Teratoma
c) Embryonal Cell Carcinoma
d) Choriocarcinoma

24. a) Germinoma :
1 Incidence
2Radiographic Features
3-Tumor Markers

25. 1-Incidence :
-Most common pineal germ cell tumor (equivalent to
seminoma in testes and dysgerminoma in ovary)
-Males predominate (10:1), age 10 to 30 years
-In females, more commonly located in suprasellar location
-Serum markers (alpha-fetoprotein) may also be
positive

26. 2-Radiographic Features :
a) CT
-Well defined slightly hyperdense mass that
engulfs a prominent calcified pineal gland
-Homogeneous intense enhancement
-Central calcification due to pineal engulfment
(rare)

31. b) MRI
-T1 : isointense or slightly hyperintense to adjacent
brain
-T2 : isointense or slightly hyperintense to adjacent
brain, may have areas of cyst formation, central
calcification appears low signal (engulfed pineal
gland)
-T1+C : vivid and homogeneous

32. T1

33. T1+C

34. T1 T2

36. 3-Tumor Markers :
HCG AFP
Germinoma - -
Embryonal cell
carcinoma
+ +
Choriocarcinoma + -
Yolk sac tumor - +

37. b) Teratoma :
1 Incidence
2 Radiographic Features

38. 1-Incidence :
-Second most common pineal germ cell tumor
-Almost exclusively in male children
-The most common congenital intracranial
tumor and are usually diagnosed prenatally
-Presence of fat and calcification is
diagnostically helpful with little to no
enhancement

39. 2-Radiographic Features :
*CT :
-Demonstrates at least some fat and some
calcification which is usually solid / clump like
-They usually have cystic and solid components,
contributing to an irregular outline, solid
components demonstrate variable
enhancement

41. CT+C , there is relatively homogeneous enhancement of the non-calcified
solid portions of the tumor , the cystic region doesn’t enhance

42. *MRI :
-T1 :
-Hyperintense components due to fat and
proteinaceous / lipid rich fluid
-Intermediate components of soft tissue
-Hypointense components due to calcification and
blood products
-T2 :
-Mixed signal from differing components
-T1+C :
-Little or no enhancement
-Solid soft tissue components show enhancement

44. T1+C shows enhancement of the soft-tissue portions of the lesion

45. Ruptured pineal region dermoid

46. 3-Choriocarcinoma, Yolk Sac Tumors and
Embryonal Carcinoma :
-Are rare neoplasms
-These neoplasms may have imaging findings
similar to those of other germ cell neoplasms or
primary pineal neoplasms
-Evaluation of tumor markers assists in making the
appropriate diagnosis
-These lesions may also hemorrhage - resulting in
T1 shortening

47. a)Sagittal T1 weighted MR
image shows an
heterogeneous pineal region
mass with foci of T1
shortening due to
hemorrhage , note the
associated hydrocephalus
b)Axial postcontrast T1-
weighted MR image shows
that the pineal region mass
also has an heterogeneous
enhancement with foci of
necrosis/cyst , involvement of
the tectal plate and both
thalami are also present (not
shown) , evaluation of serum
oncoproteins demonstrated
high level of b-hCG , biopsy of
the lesion revealed that it
corresponds to
Choriocarcinoma

48. 3-Parenchymal Cell Tumors :
a) Pineocytoma
b) Pineoblastoma

50. a) Pineocytoma :
-No male predilection
-Older age group, mean age 35 years
-Slow growing, dissemination is uncommon
-No helpful imaging features, cannot be
distinguished by imaging features from a
Pineoblastoma

52. CT+C shows homogenous enhancement of the mass which assumes a
triangular shape as it conforms to the contours of the pulvinar of
the thalami and velum interpositum

53. T1

54. T1

55. T1+C

56. b) Pineoblastoma :
-Highly malignant PNET (Primitive Neuroectodermal
Tumors)
-In patients with trilateral retinoblastoma, Pineoblastoma
may develop in patients with familial and or bilateral
retinoblastoma
-(Exploded calcifications) along outside of mass
(peripherally), unlike germinoma which engulfs and
induces calcification of the pineal gland
-Dense enhancement
-Larger, more heterogeneous with much greater
propensity for local invasion and CNS dissemination

60. Axial nonenhanced CT shows a large pineal region mass with resultant hydrocephalus ,
the pineal calcifications are exploded toward the periphery (arrows)

61. T1

62. T2

63. T1+C

64. b) Extrinsic Pineal Mass :
1 Gliomas
2Vein of Galen Aneurysm
3-Meningioma
4-Quadrigeminal Plate Lipoma

65. 1-Gliomas :
-Gliomas (most commonly astrocytomas) of
varying grade may occur in adjacent intra-axial
structures such as the tectum, midbrain or
splenium of the corpus callosum
Tectal Glioma :
a) Incidence
b) Radiographic Features

67. a) Incidence :
-Tectal plate gliomas are encountered in
children and adolescents
-Usually low grade tectal tumor causing
aqueduct stenosis
-Typically low grade astrocytoma with good
prognosis

68. b) Radiographic Features :
-CT :
-Typical CT finding is homogenous expansion of
tectal plate, isodense to grey matter with
minimal enhancement in postcontrast image

69. CT shows non-communicating hydrocephalus , note the low density lesion of
the tectal plate

71. -MRI :
-Typically the tumors demonstrate expansion of the
tectal plate by a solid nodule of tissue
*T1 :
-Iso to slightly hypointense to grey matter
*T2 :
-Hyperintense to grey matter
*T1+C :
-Usually no enhancement
-Higher grade tumors tend to be larger and tend to
enhance more vividly

72. T1

73. T2 FLAIR shows a tectal mass leading to obliteration of the
cerebral aqueduct

74. T1+C shows a slightly hypointense tectal mass which does not
enhance , the mass obstructs the aqueduct and is stable over
8 years

75. 2-Vein of Galen Aneurysm :
-Despite the name, a vein of Galen aneurysm
isn’t a true aneurysm, instead, it represents
dilatation of the vein of Galen due to an
arteriovenous fistula between the anterior or
posterior circulation and the venous plexus
leading to the vein of Galen

77. 3-Meningioma :
-The tentorial apex, adjacent to the pineal gland,
is a characteristic location for meningioma
-The tentorial meningioma tends to depress the
internal cerebral veins, in contrast to a pineal-
based mass which typically elevates the
internal cerebral veins

79. 4-Quadrigeminal Plate Lipoma :
-At CT, lipomas have low attenuation, consistent
with fat
-At MR imaging, they have the same signal
characteristics as fat (hyperintense on T1 with
saturation on fat-saturated images)
-No enhancement is seen on postcontrast
images

80. Quadrigeminal plate lipoma , (a) axial T1 , (b) sagittal T1 show a lobulated ,
hyperintense mass of the quadrigeminal plate , note the associated
thinning of the posterior body (arrow) and splenium of the corpus
callosum