Transcript Case Study - University of Pittsburgh

Case Study 49
Edward D. Plowey
Case History
 This is an outside consultation of a tumor resected from
a 14 year-old boy who presented 1 month prior to
surgery with a new onset seizure.
 Initial MRIs at the outside institution reportedly showed
a well-demarcated left temporal lobe tumor with mild
hemorrhage.
 Images from a preoperative MRI are shown in the next
slide.
Question 1: Describe the MRI findings.
T1 Pre-C
T2 FLAIR
T1 + Post C
Answer
 The MRI shows a heterogeneous, well circumscribed, 4 cm left
temporal lobe mass with minimal peri-tumoral edema. A large
component of the posterior aspect of the mass exhibits contrastenhancement.
 Note: The T1 hyperintensity from prior studies reflecting
hemorrhage had reportedly dissipated.
Question 2
 What are the most common entities that comprise the
differential diagnosis of this mass?
Answer
 The differential diagnosis would include: ganglioglioma,
dysembryoplastic neuroepithelial tumor, pilocytic
astrocytoma, low grade glioneuronal tumor, ependymoma,
oligodendroglioma.
Question 3
An intraoperative consultation was requested and
performed by remote telepathology.
Describe the smear findings in the following images and
formulate an intraoperative diagnosis:
Answer
 Low power images of the intraoperative smear demonstrate
a vascular lesion with degenerating blood.
 A high power image shows a neoplasm composed of small
round cells with open chromatin and a neurophil
background. Some of the cells with more condensed
chromatin (darker nuclei) show perivascular structuring.
No mitotic figures are seen. Tumor vessels show nonreactive endothelial cells
 Intraoperative Diagnosis:
 A. Neoplastic
 B. Low grade neurocytic tumor or Low grade glioneurocytic
tumor
Question 4
Describe the findings in the following permanent section:
Virtual Slide:
http://image.upmc.edu:8080/NeuroPathology/GlialTumors/
GlialTumor2/GT.82A.svs/view.apml?
Diagnostic Images in the following Powerpoint slides
Answer
 The histologic section
demonstrates a predominantly
neurocytic neoplasm with a
minority of cells showing larger
nuclei with more prominent
nucleoli and moderate cytoplasm
(ganglioid cells). Frank ganglion
cells are not seen. Mitotic
figures, endothelial hyperplasia
and necrosis are not seen.
Answer
 Some areas of the neoplasm
show a pseudopapillary
architecture. Hyalinazed blood
vessels are bordered by cells
with small round cells with
scant cytoplasm.
Question 5
 What immunostains do you want to order to further
characterize this neoplasm?
Answer
 Synaptophysin (click the following virtual slide hyperlink)
http://image.upmc.edu:8080/NeuroPathology/GlialTumors/GlialTumor2/GT.82B.svs/view.apml?
 NeuN (click the following virtual slide hyperlink)
http://image.upmc.edu:8080/NeuroPathology/GlialTumors/GlialTumor2/GT.82D.svs/view.apml?
 GFAP (click the following virtual slide hyperlink)
http://image.upmc.edu:8080/NeuroPathology/GlialTumors/GlialTumor2/GT.82C.svs/view.apml?
 Ki67/MIB-1
 Diagnostic images on following Powerpoint slides
Synaptophysin
NeuN
GFAP
Ki67/MIB-1
Question 6
What information do the immunostains convey?
Answer
A synaptophysin immunostain is negative in the
cytoplasm of the neurocytic cell component, but is positive
in the neurophil processes of the neurocytic component of
the tumor. A NeuN immunostain is positive in some of the
tumor cells with ganglioid differentiation. A GFAP
immunostain is strongly positive in the glial cells lining the
hyalinized blood vessels.
A Ki67/MIB-1 immunostain is positive in less that 1% of
the tumor cells.
Question 7
 What ancillary molecular diagnostic tests might be
helpful in the diagnosis?
Answer
 The histologic findings are diagnostic and obviate ancillary molecular
testing.
 1p/19q co-deletion analysis may be ordered by the pathologist that is
unfamiliar with this entity. If the patient is an adult, a negative result
could be reassuring that you are not dealing with a Grade 2
oligodendroglioma. However, a negative 1p/19q result in a child or
young adult does not rule out oligodendroglioma, and the pathologist
must rely on recognition of the characteristic histologic features to
arrive at the correct diagnosis.
Question 8
Which of the following choices is the correct diagnosis?
A. Oligodendroglioma with neurocytic differentiation
B. Atypical Extraventricular Neurocytoma
C. Ganglioglioma
D. Papillary Glioneuronal Tumor
E. Angiocentric Glioma
Answer: Choice D
Final Diagnosis: Papillary Glioneuronal Tumor, WHO
Grade 1.
Discussion
 The typical picture of the rare papillary glioneuronal tumor (PGNT)
is a well-demarcated, contrast-enhancing mass in the temporal
lobe of a young adult with new onset seizures. By most accounts,
these tumors are generally thought to be adequately treated with
gross total resection (Komori T et al. Am J Surg Pathol. 22:117183, 1998.
 As was seen in this case, presentation via cerebral hemorrhage
has been previously reported (Buccoliero A. et al., Neuropathol.
26:206-11, 2006).
Discussion
 Although this rare tumor is considered a WHO Grade 1 neoplasm,
recent reports of PGNT with elevated proliferation and tumor
recurrence suggest that PGNT should be thoroughly examined for
histologic signs of potential aggressive behavior.
 Javahery et al., J Neurosurg Pediatrics. 3:46-52, 2009.
 Newton et al. Clin Neuropathol. 27:317-24, 2008.
 Vaquero and Coca. J Neurooncol. 83:319-23, 2007.
 Ishizawa T, et al. Hum Pathol. 37:627-30, 2006.
 As is suggested in the GFAP-immunostained slide, the tumor-brain
interface is gliotic. Furthermore, Rosenthal fibers and/or
eosinophilic granular bodies can be seen. As with any tumor
showing a reactive brain border, these features could conceivably
cause diagnostic errors in biopsies taken from the tumor periphery.