Transcript Case Study - University of Pittsburgh

Case Study 3
Gabrielle Yeaney, M.D.
Question 1
A 7-year-old boy with three month history of nausea,
vomiting and headaches. Describe the MRI findings
(location, enhancement, mass effect).
Axial T1
Axial T2
Axial T1 +contrast
Coronal T1 +contrast
Answer
There is a discrete midline mass with mixed cystic and
solid components within the posterior fossa/region of the
fourth ventricle. Irregular nodular enhancement is
identified in the wall and central aspect. The tumor exerts
mass effect on the pons and midbrain. The lateral and
third ventricles are moderately dilated.
Question 2
Name at least three tumors that classically show a cystic
architecture with a mural nodule.
Answer
1. Pilocytic astrocytoma 2. Ganglion cell
tumor/ganglioglioma 3. Pleomorphic
xanthoastrocytoma 4. Hemangioblastoma 5. Supratento
rial ependymoma
Question 3
The pediatric neurosurgeon gives you a biopsy specimen
from the posterior fossa for intraoperative
diagnosis. Describe the cytologic features of the smear.
Click here to view slide.
Answer
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Small bland nuclei in a finely fibrillar background
Bipolar cells with long hair-like processes
Rosenthal fibers
Eosinophilic granular bodies
Rare mitotic figure(s)
Capillaries
Question 4
What is your intraoperative diagnosis? (A.
Neoplastic/Defer/Non-neoplastic, B. ________)
Answer
A. Neoplastic
B. Juvenile pilocytic astrocytoma
Question 5
Review the permanent section. What is your final
diagnosis?
Click here to view slide.
Answer
Juvenile pilocytic astrocytoma
Question 6
What ARCHITECTURAL feature(s) do you observe on
permanent section that was not obvious on the smear?
Answer
Loose microcystic areas are seen in addition to the
answers listed in the answer for question 3. These less
cellular areas are suggested on the smear but are not as
easily appreciated.
Question 7
The bipolar astrocytes in this lesion are thought to
produce dense eosinophilic aggregates called
____________ on H&E light microscopy.
Answer
Rosenthal fibers are usually seen in the compact areas of
JPA. While helpful, they are not required for the diagnosis
of JPA, nor are they specific for JPA.
Question 8
In this neoplasm in general (not necessarily this case),
what histologic feature would be most concerning for
more aggressive behavior (higher grade lesion)?
A.Glomeruloid vessels
B.Mild nuclear atypia
C.Brisk mitotic activity
D.Meningeal infiltration
E.All of the above
Answer
The correct answer is C. JPA may contain glomeruloid
vessels, nuclear atypia and meningeal
infiltration. However, mitotic figures should be infrequent,
and the Ki-67/MIB-1 labeling rate is usually very low (01%). Extension into the subarachnoid space is common,
particularly in lesions of the optic nerve and cerebellum,
and is not a sign of aggressive behavior. Glomeruloid
microvascular proliferation, as a solitary feature, is
common and is more often present in the cyst wall. On
the other hand, hyperplasia of endothelial cells in larger
vessels is rarely seen. Focal infarct-like necrosis may
also be noted.
Question 9
Name three CNS neoplasms with eosinophilic granular
bodies.
Answer
1. Ganglion cell tumor/ganglioglioma 2. Pilocytic
astrocytoma 3. Pleomorphic xanthoastrocytoma