PAPILLARY LESIONS OF CNS

1. Papillary Tumors of Central Nervous
System
PRESENTER:DR.ARGHA BARUAH
MODERATOR:DR.CSBR PRASAD

3. Approach:
1)Age
2)Location
3)Key Histological features

4. Age:
• Children: Choroid plexus papilloma,Choroid plexus carcinoma,ATRT, Yolk
sac tumor, Astroblastoma
• Young adults: Papillary ependymoma and myxopapillary ependymoma
• Middle age: Papillary meningioma, Papillary craniopharyngioma
• Old age: Metastasis to CNS
• Wide range:Papillary glioneuronal tumor

5. Location
• Ventricles: Choroid plexus papilloma and Choroid plexus carcinoma
• Spinal cord: Ependymoma
• Cerebral hemisphere: Astroblastoma,ATRT,Papillary glioneuronal
tumor,Metastasis
• Suprasellar: Craniopharyngioma,Yolk sac tumor
• Pineal: Papillary tumor of pineal gland,Yolk sac tumor

6. Key histopathological features:
• Pseudorosettes: Astroblastoma, Papillary meningioma, Ependymoma
• Rhabdoid cells: ATRT
• Nonkeratinizing squamous epithelium: Papillary Craniopharyngioma
• Schiller duval bodies and hyaline globules : Yolk sac tumor
• Myxoid: Myxopapillary ependymoma
• Cell are more spindle: Astroblastoma
• Cells have single layer of monomorphic cuboidal cells: Choroid plexus papilloma
• Cells are discohesive: Papillary meningioma

7. Choroid plexus tumors
Representing 2–4% of pediatric brain tumors
This group comprises of three entities:
• Choroid plexus papilloma (CPP; WHO grade I),
• Atypical CPP (WHO grade II),
• Choroid plexus carcinoma (CPC; WHO grade III).
Patients present with signs of hydrocephalus and raised intracranial
pressure

9. Choroid plexus carcinoma

10. • Immunohistochemically CPC express CK showing less frequent
positivity for S-100 and transthyretin.
• Mean Ki-67/MIB-1 labeling indices reported for CPP and CPC are 1.9%
and 13.8%, respectively.

11. Papillary ependymoma
• Papillary ependymoma is generally a slow growing tumor affecting children
and young adults, histologically corresponding to WHO grade II.
• It is most commonly seen in the fourth ventricle and spinal cord, followed
by the lateral ventricles and the third ventricle.
• Supratentorial ependymomas manifest with focal neurological deficits,
seizures, and features of intracranial hypertension
• Infratentorial ependymomas present with hydrocephalus and raised
intracranial hypertension.

12. Immunopositivity for S-100, vimentin, epithelial membrane antigen (EMA), and nestin is also seen.

13. Myxopapillary ependymoma
• Slow growing tumor manifesting in young adults typically involving the conus
medullaris, cauda equina, and filum terminale of the spinal cord and corresponds
to WHO grade I.
• The frequency of this tumor is 9-13% among all ependymomas.
• The mean age of 36 years has been reported with a male: female ratio of 2.2:1.
• It typically presents with back pain of long duration
• Prognosis is extremely favourable.

14. Immunohistochemistry for GFAP, S-100, and vimentin is positive.

15. Astroblastoma
• Rare glial neoplasm mainly affecting children, adolescents, and young
adults, typically involving the cerebral hemispheres.
• Due to the insufficient epidemiological and clinicopathologic data, this
tumor still awaits a WHO grade.
• Cytoplasmic immunopositivity for vimentin, S-100, and GFAP is
characteristic.
• Cytoplasmic immunopositivity for vimentin, S-100, and GFAP is
characteristic.

17. Papillary meningioma
• Rare tumors
• These are highly aggressive tumor corresponding to WHO grade III with a tendency to invade, recur, and
metastasize.
• Majority arise in intracranial (cerebral convexities), intraspinal (thoracic regions), or orbital locations.
• Middle aged patients, the female: male ratio is 1.7:1.
• Clinically, headache and seizures are the common presenting features.
• Diagnosis of papillary meningioma is considered only when this architectural pattern is exhibited in > 50% of
the tumor.
• Immunopositivity for EMA, vimentin, and S-100 is characteristic. Mean Ki-67/MIB-1 labeling indices reported
for papillary meningioma are generally > 20%.

19. Papillary glioneuronal tumor
• This neoplasm being extremely rare still lacks a population-based epidemiologic data.
• This tumor manifest over a wide range of ages (4–75 years); the mean age at presentation being
27 years.
• There is no gender bias.
• It corresponds to WHO grade I.
• It shows a predilection for the temporal lobes.
• Headache and seizures are the main clinical features
• Immunohistochemically, the glial cells are GFAP positive while the interpapillary cells are
synaptophysin,neuron specific enolase (NSE), and NeuN positive. MIB-1 labeling indices are in the
range of 1–2%.

21. Atypical teratoid/rhabdoid tumor
• Highly malignant CNS tumor (WHO grade IV), occurring most frequently in
infants, with most patients being aged less than 3 years
• Male: female ratio ranges from 1.6 to 2:1 showing a consistent male
predominance.
• ATRTs account for 1–2% of pediatric brain tumors and approximately 10%
of the infantile CNS tumors.
• This tumor may occur in either supratentorial or infratentorial location,
the ratio of supratentorial to infratentorial being 1.3:1.

23. • Rhabdoid cells are immunopositive for EMA, vimentin, and
smooth muscle actin (SMA).
• Expression of GFAP, neurofilament protein (NFP),
synaptophysin, and keratins are also common .
• Currently, INI1 is considered the most sensitive and specific
marker for ATRTs.
• Ki-67/MIB-1labeling indices reported for ATRTs are often > 50%,
focally up to 100%

24. Papillary Craniopharyngioma
• Papillary craniopharyngioma, the recently identified variant of craniopharyngioma, typically
affects the adults (mean age 40-55 years) involving the suprasellar region or the third ventricles.
• It is a benign tumor and corresponds histologically to WHO grade I.
• Craniopharyngiomas in general account for 1.2-4.6% of all intracranial tumors.
• Male and female are equally affected.
• Clinical features include visual loss,endocrine deficiencies, raised intracranial tension, diminished
mental acuity, and personality changes.
• MIB-1 immunopositivity is randomly distributed and are considerably higher than might be
expected considering the benign nature of the neoplasm.

26. Yolk Sac Tumor
• The incidence of this tumor varies geographically.
• All age groups affected but majority affect patients aged younger than 25
years.
• This tumor is more common in males.
• Midline location (third ventricle, pineal region) is the most common
followed by the suprasellar compartment.
• Clinical presentation varies according to the location.

27. • Periodic acid Schiff (PAS) positive/diastase resistant, variably sized,
cytoplasmic hyaline globules lying within the epithelial cells or
in the stroma. Mitosis is variable.
• Immunohistochemistry shows diagnostic cytoplasmic positivity for
alpha fetoprotein (AFP).

29. Papillary tumor of the pineal region
• Papillary tumor of the pineal region (PTPR) is a recently recognized
rare neuroepithelial tumor that occurs exclusively in the pineal
region, most often in adults.
• Incidence is not determined till date because of the rarity of this
neoplasm.
• Similarly histological grading criteria remain to be identified.PTPR has
been identified in both children and in adults (mean age 32 years).

31. • Immunohistochemistry shows strong positivity for keratins in the
papillary structures.
• PTPRs also show immunopositivity for vimentin, S-100, NSE,
microtubule associated protein 2 (MAP2), Neural cell adhesion
molecule(N-CAM), and transthyretin
• The Ki-67/ MIB-1 labeling indices reported for PTPRs are moderate
showing higher indices in tumors of young patients.

32. Metastatic Tumors of the CNS
• Metastatic tumors are the most common CNS neoplasms.
• The incidence of CNS metastases increases from < 1/100,000 below 25
years of age to > 30/100,000 at the age of 60 years.
• The most common sources of brain metastases in adults are, in descending
order, lung cancer, breast cancer, melanoma, renal cancer, and colon
cancer; in children, in descending order, leukemia, lymphoma,osteogenic
sarcoma, rhabdomyosarcoma, and Ewing sarcoma.
• The most common location for CNS metastases is the cerebral
hemispheres, followed by cerebellum.

33. • Immunohistochemical expression is variable.
• CNS metastases of the carcinomas usually show strong
immunopositivity for CK and EMA
• The Ki-67/MIB-1 labeling indices reported for metastatic tumors
of the CNS are markedly high

37. Summary
• Basic approach is first check the age
• Correlate with radiological findings especially for the location
• Check for key histological features
• Run IHC only when in doubt and to rule out primary origin of
metastatatic lesions.

38. References:
• Pant I, Chaturvedi S. Diagnostic approach to histopathology of central
nervous system papillary tumors. Astrocyte 2014;1:124-31
• Suki D. The epidemiology of brain metastases. In: Intracranial
metastases; Current management strategies. In: Sawaya R, editor.
Malden, MA, USA: Blackwell Futura Publishing; 2004.