Pediatric Posterior Fossa Tumors:
Diagnosis and follow up
Esther de Luis MD. PhD.
Hospital Universitario Madrid MontepríncipeSpain
Clínica Universitaria de Navarra- Spain
Hospital San Javier Guadalajara Mexico
Pediatric Posterior Fossa Tumors
• CNS tumors are the second most common
pediatric tumors being exceed only by leukemya
• Supratentorial and posterior fossa tumors occur
in nearly equal frequency
• Supratentorial tumors are more frequent in the
first 2-3 years of life whereas infratentorial
predominate from ages 4-10 years
Objectives
• Describe the intraparenchymal posterior fossa
tumors in children and their imagining
findings (MR and CT) and the importance of
diffusion and spectroscopy in the differential
diagnosis of these tumors
• Review the most common complications that
occur during treatment and the importance of
the radiologic follow up
Pediatric Posterior Fossa Tumors
• The most common posterior fossa tumors in
children are medulloblastoma, astrocytoma
and ependymoma
• The accurate diagnosis of these lesions is
important to ensure that patients receive
adequate therapy and prognostic information
Medulloblastoma
• Primitive Neuroectodermal Tumor of the posterior fossa (PNET)
• Tumor with neuroblastic or glioblastic elements (embryonal tumor)
• May appear intraventricular its origin is vermis cerebellar
parenchyma
• Children 6-11 years old
• Males 2-4 times than females
• The duration of symptoms is short: nausea, vomiting (area
postrema), lethargy in small children and ataxia in older
• Spinal metastases are present in initial diagnosis 30% cases
• Extent of disease is the most important predictive prognosis
• Increased frequency: Basal cell nevus syndrome
Medulloblastoma
1 year 4 months old female. Vomiting and lethargy
Medulloblastoma
1 year 4 months old female. Vomiting and lethargy
Medulloblastoma
1 year 4 months old female. Vomiting and lethargy
Medulloblastoma
1 year 4 months old female. Vomiting and lethargy
Medulloblastoma
1 year 4 months old female. 2 months after surgery
Medulloblastoma
5 years old female.
Medulloblastoma removed 2 year before. Chemo and radiotherapy
Medulloblastoma
5 years old female.
Medulloblastoma removed 2 year before. Chemo and radiotherapy
Medulloblastoma
16 years old male.
Medulloblastoma removed 1 year before. Radiotherapy no chemotherapy
Cerebellar Astrocytoma
• 60% of astrocytomas in children are located in the posterior fossa: 40%
cerebellum and 20% in the brainstem
• Most common astrocytoma in children are of a specific type: Juvenile
Pilocytic Astrocytoma (JPA): grade I WHO
• JPA most benign astroglial tumor of CNS
• JPA equal frequency males and females. 70% astrocytomas in children
• Peak of incidence 8 years
• Older children more frequent anaplastic astrocytoma
• Symptoms: early morning headache and vomiting
• Originate in midline, 30% extend into cerebellar hemispheres
• 25% are solid
• JPA excellent prognosis 90% survival rate after 25 years
• Malignant transformation is exceeding rare
• Gross total resection is curative
• Tumors non surgically accessible: stereotactic radiosurgery
Cerebellar Astrocytoma: JPA
15 years old female. Biopsy confirmed JPA
Cerebellar Astrocytoma: JPA
15 years old female. Biopsy confirmed JPA
Cerebellar Astrocytoma: JPA
15 years old female. Biopsy confirmed JPA
Ependymoma
• Constitute 8-12% primary CNS neoplasm in children and 815% posterior fossa tumors
• Ependymal cell tumors: floor and roof of fourth ventricle
• WHO grade II
• The relative frequency diminishes as children grow up, they
can appear at any age
• In children are more common infratentorial (70%)
• Slightly more frequent in males
• Two age peaks: 1-5 years and four decade
• Long clinical history
• Nausea and vomiting, hydrocephalus (90%), torticollis,
ataxia and lower cranial neuropathies(foramen of Luschka)
Ependymoma
Ependymoma
Atypical rhabdoid teratoid tumor
•
•
•
•
•
Younger age than PNET
Median age at diagnosis less than 2 years of age
Lack of response to standard therapy
Special microscopic techniques
Rhabdoid cells: small round cells (only a minority
of the tumor)
• Cerebellum most common site
• May spread through the subarachnoid space
• Imaging similar to medulloblastoma, calcification
is common, necrosis, cysts and hemorrhage
Brainstem Tumors
• Constitute 15% of all pediatric CNS tumors and 20-30%
of infratentorial brain tumors
• Peak of incidence 3-10 years of age
• Different types:
– Medullary tumors
– Pontine tumors
– Mesencephalic tumors
•
•
•
•
Focal or diffuse
Histology: astrocytoma, ganglioglioma, lymphoma
The most frequent astrocytoma
More frequent in NF 1
Brainstem Tumors: Medullary
15 years old male. JPA confirmed
Brainstem Tumors: Pontine
9 years old male. Glioma grade II WHO
Brainstem Tumors: Mesencephalic
19 years old female.
JPA
Brainstem: Quadrigeminal plate
16 years old female
Brainstem Tumors: differential diagnosis
Conclusions
• It is important to know the best imaging
technique and be familiar with the most
common complications that occur during and
after treatment
• Radiologists play an important role not only in
the diagnosis but also in the follow up of
children with posterior fossa tumors
References
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Gallucci M, Catalucci A, Scheithauer BW, Forbes GS. Spontaneous involution of pilocytic astrocytoma in a patient without neurofibromatosis type 1:
case report. Radiology. 2000 Jan;214(1):223-6.
Hemant Parmar . Cynthia Hawkins . Eric Bouffet . James Rutka . Manohar Shroff . Imaging findings in primary intracranial atypical teratoid/rhabdoid
tumors. Pediatr Radiol (2006) 36: 126–132
Severino M, Schwartz ES, Thurnher MM, Rydland J, Nikas I, Rossi A. Congenital tumors of the central nervous system. Neuroradiology. 2010
Jun;52(6):531-48
Garrè ML, Cama A, Bagnasco F, Morana G, Giangaspero F, Brisigotti M, Gambini C, Forni M, Rossi A, Haupt R, Nozza P, Barra S, Piatelli G, Viglizzo G,
Capra V, Bruno W, Pastorino L, Massimino M, Tumolo M, Fidani P, Dallorso S, Schumacher RF, Milanaccio C, Pietsch T. Medulloblastoma variants: agedependent occurrence and relation to Gorlin syndrome--a new clinical perspective. Clin Cancer Res. 2009 Apr 1;15(7):2463-71.
Vazquez E, Castellote A, Mayolas N, Carreras E, Peiro JL, Enríquez G. Congenital tumours involving the head, neck and central nervous system. Pediatr
Radiol. 2009 Nov;39(11):1158-72.
Barkovich AJ. Neuroimaging of pediatric brain tumors. Neurosurg Clin N Am. 1992 Oct;3(4):739-69.
Takanashi J, Miyamoto T, Ando N, Kubota T, Oka M, Kato Z, Hamano S, Hirabayashi S, Kikuchi M, Barkovich AJ. Clinical and Radiological Features of
Rotavirus Cerebellitis. AJNR Am J Neuroradiol. 2010 May 27.
Yuh EL, Barkovich AJ, Gupta N. Imaging of ependymomas: MRI and CT. Childs Nerv Syst. 2009 Oct;25(10):1203-13.
Gyure KA. Newly defined central nervous system neoplasms. Am J Clin Pathol. 2005 Jun;123 Suppl:S3-12.
Hasselbalch B, Eriksen JG, Broholm H, Christensen IJ, Grunnet K, Horsman MR, Poulsen HS, Stockhausen MT, Lassen U. Prospective evaluation of
angiogenic, hypoxic and EGFR-related biomarkers in recurrent glioblastoma multiforme treated with cetuximab, bevacizumab and irinotecan. APMIS.
2010 Aug;118(8):585-94.
Pytel P, Lukas RV. Update on diagnostic practice: tumors of the nervous system. Arch Pathol Lab Med. 2009 Jul;133(7):1062-77.
Rieken S, Gaiser T, Mohr A, Welzel T, Witt O, Kulozik AE, Wick W, Debus J, Combs SE. Outcome and prognostic factors of desmoplastic
medulloblastoma treated within a multidisciplinary treatment concept. BMC Cancer. 2010 Aug 23;10(1):450.
Muzumdar D, Ventureyra EC. Treatment of posterior fossa tumors in children. Expert Rev Neurother. 2010 Apr;10(4):525-46.
Allen JC, Donahue B, DaRosso R, Nirenberg A. Hyperfractionated craniospinal radiotherapy and adjuvant chemotherapy for children with newly
diagnosed medulloblastoma and other primitive neuroectodermal tumors. Int J Radiat Oncol Biol Phys. 1996 Dec 1;36(5):1155-61.
Friedman HS, Prados MD, Wen PY, Mikkelsen T, Schiff D, Abrey LE, Yung WK, Paleologos N, Nicholas MK, Jensen R, Vredenburgh J, Huang J, Zheng M,
Cloughesy T. Bevacizumab alone and in combination with irinotecan in recurrent glioblastoma. J Clin Oncol. 2009 Oct 1;27(28):4733-40.
Kalifa C, Grill J. The therapy of infantile malignant brain tumors: current status? J Neurooncol. 2005 Dec;75(3):279-85.
Smith AB, Rushing EJ, Smirniotopoulos JG. Pigmented lesions of the central nervous system: radiologic-pathologic correlation. Radiographics. 2009
Sep-Oct;29(5):1503-24.
Pediatric Neuroimaging. A.J.Barkovich. Lippincott forth edition
Diagnostic Imaging. Brain. Osborn A. AMYRSIS