Case Study 41
Henry Armah, M.D., M.Phil.
Question 1
Clinical history: 41-year-old male presenting with
headache, mild left-sided weakness, restlessness,
confusion and behavioural changes. Describe the
abnormal cranial MRI findings?
Axial T1
Axial T2
Ax T1+C
Answer
Large heterogenously contrast rim-enhancing right frontal
lobe mass with central region showing no enhancement
suggestive of necrosis, significant perilesional edema and
significant mass effect with midline shift to the left.
Question 2
What are your differential diagnoses based on the
patients’ age and the radiological findings?
Answer
1. High-grade Glioma
2. Supratentorial Primitive Neuroectodermal Tumor (PNET)
3. Abscess
4. Malignant Lymphoma
5. Metastases
Question 3
The neurosurgeon performs a craniotomy with resection
of the mass, and requested an intraoperative consultation.
Describe the microscopic findings on this smear slide?
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Answer
Neoplastic proliferation of round-to-oval pleomorphic
tumor cells with scant cytoplasm, scattered mitotic figures,
and several apoptotic bodies.
Question 4
What is your intraoperative diagnosis? (A: Category such
as Defer, Reactive/Non-neoplastic, or Neoplastic; B: More
specific diagnosis or statement)
Answer
A. Neoplasm
B. Undifferentiated High-grade Tumor
Question 5
The permanent section has returned from histology.
Describe the microscopic findings on this H&E slide?
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Answer
Fragments of a malignant neoplasm mainly composed of
undifferentiated neuroepithelial cells with small round
nuclei and high nucleus: cytoplasm ratios. There are focal
areas of tumor cells with oval-to-elongated nuclei and
fibrillary cytoplasm. There is anaplasia and brisk mitosis.
Karyorrhectic, apoptotic and pyknotic nuclei are readily
identified. Endothelial proliferation is noted. Rare small
foci of necrosis are appreciated, but no pseudopalisading
necrosis is present. Rare tumor cells with vesicular
chromatin, nucleoli and Nissl substance are noted. There
is no evidence of medullary-type epithelium, neuroblastic
(Homer-Wright) rosettes, or ependymoblastic rosettes.
Question 6
What additional immunohistochemical studies would you
need to rule out other important differential diagnoses and
confirm the final diagnosis in this case?
Answer
1. GFAP
2. EGFR
3. p53
4. Ki-67 (MIB-1)
5. Synaptophysin
6. CAM5.2
7. LCA (CD45)
Question 7
What do you see on this GFAP immunostain slide?
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Answer
GFAP strongly stains the reactive glial tissue and
occasional tumor cell processes.
Question 8
What do you see on this EGFR immunostain slide?
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Answer
EGFR is strongly and patchy positive in the tumor cells.
Question 9
What do you see on this p53 immunostain slide?
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Answer
p53 is not clonally expressed in the nuclei of tumor cells,
but only positive in the nuclei of a few tumor cells.
Question 10
What do you see on this Ki-67 (MIB-1) immunostain
slide?
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Answer
Ki-67 (MIB-1) is positive in the nuclei of 20-25% of the
tumor cells.
Question 11
What do you see on this Synaptophysin immunostain
slide?
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Answer
Synaptophysin show focal granular and rare diffuse
cytoplasmic staining of tumor cells, with no evidence of
neuropil formation.
Question 12
What do you see on this CAM5.2 immunostain slide?
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Answer
CAM5.2 is negative in tumor cells.
Question 13
What is your final diagnosis in this case?
Answer
Supratentorial Primitive Neuroectodermal Tumor (PNET)
with Glial Differentiation
Question 14
What is the corresponding WHO grade of this lesion?
Answer
WHO Grade 4