Case Study 12
Gabrielle Yeaney, M.D.
Question 1
19-year-old man with a past medical history of ALL who
presents with a several week history of intermittent falls
secondary to his legs giving out on him. He also
describes sensory changes in his legs bilaterally.
Describe the MRI findings (location, enhancement,
mass effect).
MRI sagittal T1 w/o and w/contrast
MRI axial T2
Answer
MRIs show an enhancing intradural, extramedullary mass
at the thoracic (T6-T7) level on the right side extending
through a neural foramen causing compression of the
spinal cord.
Question 2
What is in the differential diagnosis of an intradural,
extramedullary spinal lesion?
Answer
 Schwannoma
 Meningioma
 Hemangiopericytoma
 Solitary fibrous tumor
 Melanocytic neoplasm
 Inflammatory / infectious (sarcoidosis, TB)
 Vascular malformation
 Mesenchymal chondrosarcoma
 For this case specifically, you could include chloroma since the
patient has a history of ALL, but it would be unusual.
Question 3
You are called for an intraoperative consultation. A
squash preparation is performed. Due to the firmness of
the tissue, a frozen section is also done. What is your
intraoperative diagnosis? (A. Neoplastic/Defer/Nonneoplastic, B. ________)
Click here to view slides.
Answer
A. Neoplastic
B. Schwannoma
Question 4
Review the permanent section. What are the classic
architectural features seen in this neoplasm?
Click here to view slide.
Answer
This classic biphasic pattern is shown with compact
(Antoni A) and loose (Antoni B) areas. Verocay bodies,
foci with nuclear palisading, are present in Antoni A areas.
Question 5
Sometimes this tumor can appear histologically similar to
fibrous meningioma or tanycytic ependymoma, given the
cellular elongation and spindled patterns in all. What
immunohistochemical stains would you use to
differentiate the neoplasms? Give a panel of at least 3
markers and state whether positive or negative.
Answer
An immuno-panel including S100, epithelial membrane
antigen (EMA) and glial fibrillary acidic protein (GFAP)
would be useful. The following staining patterns are
expected: meningioma (S100 -, EMA +, GFAP -);
ependymoma (S100 +, EMA may have focal dot-like
cytoplasmic reactivity, GFAP ++ especially in
pseudorosettes); schwannoma (S100 ++, EMA -, GFAP
may have patchy reactivity). Schwannomas have more
reticulin fibers (not an immunostain) and stronger
expression of collagen IV and laminin than tanycytic
ependymomas.
Question 6
What is "ancient change"?
Answer
Ancient change is nuclear pleomorphism and
hyperchromasia and is frequently seen in
schwannomas. This "atypia" represents a degenerative
phenomenon rather than a true neoplastic
atypia/anaplasia, as it is not associated with cell
proliferation. Schwannomas can have vascular
hyalinization, stromal myxoid change and cystic change.
Question 7
What hereditary disease is associated with finding
multiple tumors like this?
Answer
Neurofibromatosis 2 (central neurofibromatosis) is an
autosomal dominant disorder associated with
schwannomas. The NF2 gene is found on chromosome
22q12, and its gene product is merlin, or
schwannoma. Bilateral vestibular schwannomas and/or
meningiomas, multiple cutaneous/craniospinal
schwannomas, glioma, lens opacity (cataract) are
associated.
Question 8
True or False. In general, malignant peripheral nerve
sheath tumors arise from this neoplasm.
Answer
False. MPNST is a malignant tumor arising from or
differentiating towards cells intrinsic to peripheral nerves,
but it should nto be viewed as a malignant counterpart to
schwannoma. True malignant schwannomas are
exceedingly rare. MPNSTs are often seen in association
with NF1 (von Recklinghausen disease), and half of
MPNSTs are derived from neurofibromas.
Question 9
What is the prognosis and standard treatment for this
neoplasm?
Answer
Most classic schwannomas are cured surgically.