Transcript Case Study - University of Pittsburgh

Case Study 53
Edward D. Plowey
Case History
 The patient is a 20 year old male with no significant
past medical history, who presented with a new-onset
severe headache, nausea, photophobia and recent
onset blurry vision.
 The severity of the symptoms precipitated a CT scan
and MRI.
CT w/o Contrast
T1
T2
T1 POST-CONTRAST
Question 1
Describe the radiologic abnormalities in the following CT
and MRI images.
Answer
A non-contrast CT image shows a densely calcified heterogeneous
mass lesion within the body of the left lateral ventricle. A T1 weighted
image shows an irregular 6 centimeter mass in the body of the left
lateral ventricle associated with the septum pellucidum. Following
intravenous contrast administration there is subtle enhancement of
the intraventricular mass; no abnormal parenchymal enhancement is
identified. There is hydrocephalus of the lateral and 3rd ventricles and
midline shift from left to right. A T2 image shows no significant
transependymal CSF accumulation, suggesting chronic,
accommodated hydrocephalus. The mass extends inferiorly into the
foramen of Monro and superior aspect of the 3rd ventricle (not
shown). No potential metastatic lesions were seen.
Question 2
What is the differential diagnosis for this lesion?
Answer
The differential diagnosis of this lesion includes:
CENTRAL NEUROCYTOMA
EPENDYMOMA
CHOROID PLEXUS PAPILLOMA
MENINGIOMA
CALCIFIED REMOTE HEMATOMA
Question 3: Intraoperative Consultation
 The patient was taken to the operating room for left frontal
craniotomy and resection via endoscopic port.
 The surgeons’ impression was that the tumor was indeed
associated with the septum pellucidum.
 An intraoperative consultation was requested to confirm the
clinical impression of central neurocytoma.
 Identify the findings and render a diagnosis for the intraoperative
smear preparation.
Answer
 The intraoperative smear shows fragments of mineralized tissue
and areas of a densely cellular neoplasm comprised of
monotonous cells with round nuclei showing granular chromatin.
The internuclear areas have a neuropil-like quality with
exceedingly delicate processes appearing to emanate from some
of the cells. Mitotic activity is not seen. Occasional delicate
vessels are seen but there is no endothelial hyperplasia.
 What is your Intraoperative Diagnosis?
Answer
Intraoperative diagnosis:
A. Neoplastic.
B. Central neurocytoma.
Question 4: Permanent Sections
Examine the following virtual permanent section slides
and describe your findings:
Permanent of Frozen Section Tissue
Additional Permanent Section
Answer
 Consistent with the intraoperative cytology, permanent sections
demonstrate a neurocytic neoplasm with areas of confluent
sclerosis and calcifications. Neuropil-like processes are seen
between cells in densely cellular regions, but neuropil rosettes are
not seen in this sample. There are no high grade features
consistent with the intraoperative impression. Foci of the tumor
show perinuclear clearing reminiscent of “fried egg” artifact seen
in oligodendroglioma. No parenchymal infiltration is seen. Rare
foci of tumor necrosis are seen.
 Question 5:
 What immunostains will you order to confirm your diagnostic
impression?
Answer
 Useful immunostains include the following:
 Synaptophysin (click to view virtual slide)
 Ki67 (click to view virtual slide)
 NeuN
 GFAP
 EMA
Question 6
What information do the special stains convey?
What is the final diagnosis?
Answer
 The synaptophysin immunostain is diffusely and strongly positive
in the neoplasm. Immunoreactivity is more intense in the
intracellular neuropil processes than in the perinuclear cytoplasm,
confirming predominantly neuronal differentiation.
 The Ki67 immunostain shows a very low proliferative index of 1%.
 A NeuN immunostain often shows nuclear reactivity
neurocytomas. GFAP and EMA immunostains would be negative
in this tumor.
 Final Diagnosis: CENTRAL NEUROCYTOMA, WHO GRADE 1.
Discussion
This case highlights the classic presentation, location, histologic
features and immunoreactivity profile of central neurocytoma.
Transmission electron microscopy remains an option for tumors that do
not react with neuronal markers (synaptophysin, NeuN, neuron specific
enolase). Ultrastructural features suggestive of neurocytoma include
processes with microtubules, dense core synaptic vesicles and
rudimentary synaptic densities.
The presence of a small focus of necrosis has no significance in this
tumor which shows no high grade features.
The prognosis of central neurocytoma is excellent. This patient’s
underwent subtotal resection of his tumor. Residual third ventricular
tumor was well controlled with gamma-knife radiosurgery at 1 year
follow-up.
Discussion
Oligodendroglioma is an important entity in the differential diagnosis of
neurocytoma, especially extraventricular neurocytoma. Differentiation of
these two entities has critical clinical implications.
The following observations make this differential diagnosis challenging:
1. Oligodendrogliomas can show neurocytic differentiation (Perry et al, 2002).
2. Neurocytomas can mimic oligodendroglial histopathologic features, as in
this case (perinuclear clearing artifact and a delicate capillary vasculature).
1p/19q co-deletion has been “reported” in approximately 25% of
extraventricular neurocytoma (Rodriquez FJ et al., 2009). Co-deleted
tumors show elevated proliferative indices and propensity for recurrence,
and thus are similar to oligodendroglioma in terms of molecular
abnormalities and clinical behavior. Thus such tumors might better be
diagnosed as the Oligodendrogliomas they are ;-)
Discussion
 1p/19q co-deletion by FISH is not found in central neurocytoma
(Perry et al., 2003). However, to test the remote possibility that our
tumor represented an exophytic or intraventricular
oligodendroglioma, we performed 1p/19q co-deletion FISH analysis.
The central neurocytoma in this case did not show 1p/19q codeletion.
References
Perry A, Scheithauer BW, Macaulay RJ, Raffel C, Roth KA, Kros JM. (2002).
Oligodendrogliomas with neurocytic differentiation. A report of 4 cases
with diagnostic and histogenetic implications. J Neuropathol Exp Neurol.
61:947-55.
Perry A, Fuller CE, Banerjee R, Brat DJ, Scheithauer BW. (2003). Ancillary
FISH analysis for 1p and 19q status: preliminary observations in 287
gliomas and oligodendroglioma mimics. Front Biosci. 8:a1-9.
Rodriguez FJ, Mota RA, Scheithauer BW, Giannini C, Blair H, New KC, Wu
KJ, Dickson DW, Jenkins RB. Interphase cytogenetics for 1p19q and
t(1;19)(q10;p10) may distinguish prognostically relevant subgroups in
extraventricular neurocytoma. (2009). Brain Pathol. 19:623-9.