Case report
A 36 years old female patient referred to neurosurgery department, Razi
hospital of Birjand, Iran, with the chief complaint of aphasia for 2
month duration. Her past medical history was not significant. Her family
history was not noticeable. On examination, the patient was afebrile,
with normal vital signs. Tongue was in midline. She had full strength in
all extremities and had no other neurologic symptoms. Her laboratory
tests were unremarkable. Brain CT scan and T1-weighted, T2-weighted and
post-contrast MRI Images were made. T1-weighted MRI showed a large mass
with mixed isointense to hypointense signals in left frontoparietal
lobe; T2- weighted MRI showed isointense to hyperintense signals;
post-contrast MRI showed a mass with heterogeneous enhancement in the
left frontoparietal lobe. CT scan demonstrating a large mass with
isodensity signals (Figure 1). A preoperative diagnosis of astrocytoma
was suspected. It was decided that the patient would undergo surgery.
Stereotaxic surgery was performed and the tumor was completely removed.
The biopsied tissues were processed to formalin fixed paraffin embedded
(FFPE) preparation, hematoxylin and eosin (H&E) and
immunohistochemistry (IHC). Immunohistochemical analysis was performed
for CD99 immunomarker. Reverse transcription polymerase chain reaction
(RT-PCR) was done to assess gene rearrangement for EWSR1 gene.
The tumor was sent for histopathological examination. On microscopic
examination, at lower power, the tumor was undifferentiated and densely
cellular. Sheets of small, round to oval, uniform cells with scant clear
cytoplasm were seen infiltrating the brain tissue. Some large
pleomorphic cells were also evident (Figure 2). Histopathologic findings
were suggestive of a malignant small round cell tumor with following
differential diagnosis: 1- Ewing sarcoma / primitive neuroectodermal
tumor (PNET); 2- neuroblastoma; 3-lymphoma. Immunohistochemical analysis
showed diffuse membranous positivity for CD99 but negative staining for
LCA. Reverse transcription polymerase chain reaction showed EWSR1 gene
rearrangement and confirmed the diagnosis of PNET. Whole-body CT scan
was recommended and performed and did not demonstrate any lesion in
other parts of her body.
After surgery, the patient’s condition was stable and after two months,
the patient’s aphasia gradually resolved. Six months after surgery,
follow-up images including MRI of the patient’s brain and whole body
scans were performed. There was no evidence of tumor recurrence in these
images and no metastatic focus was evident in the images.