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Cytologic features:
[Click
here to see a case]
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Large and bizarre nuclei with
eccentric location.
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Prominent and eosinophilic
nucleoli.
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Big rhabdoid cells with a pink
cytoplasmic blob.
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Large variation in cell size.
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A medulloblastoma like component is
often present.
Other helpful features:
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Usually occur before 2 years of
age.
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Uncommon.
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Often, but not always, seen in the
posterior fossa.
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Cytologic features:
-
This preparation is
obtained from the cerebellum. Therer are some large and atypical
cells and some small cells.
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The small, naked
nuclei are from internal granular layer (Ú)
and they must not be mistaken as the larger tumor cells (Ú).
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Nucleoli is uncommon in
medulloblastoma. When it is present, it is usually not prominent. A
medulloblastoma looking tumor with prominent nucleoli prompt the
suspicion of an AT/RT.
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The medulloblastoma cells often look bigger and
have more variation in nuclear size than what it appear on frozen or
permanent sections.
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Cytoplasm of
medulloblastoma cells is usually limited to a
thin rim.
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Nuclear groove
(Ú) can be
seen in many medulloblastoma cells in cytologic preparation. However,
they are hardly seen in histologic sections.
-
Click here to see another cytologic preparation of medulloblastoma.
Other helpful features:
-
Medulloblastomas are most common in
infants and young children but they may also be seen in older
patients.
-
Medulloblastomas, by definition,
arise from the posterior fossa.
-
Medulloblastoma is a relatively
common tumor.
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Cytologic features:
[Click here to see a
case]
-
They have long cytoplasmic
processes that are characteristic of glial neoplasms on squash
preparation.
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The nuclei are round and seem to be
"rigid". They do no deform in the same direction as the
cytoplasm being squeezed as being commonly seen in squashed
preparations of astrocytomas.
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The nuclear size is suprisingly
uniform.
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Small nucleoli or dense chromatin
chromatin clumps.
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Rather open chrmoatin.
Other helpful features:
-
Although common in children, they
can occur in all age.
-
Both supra- and infratentorial
tumors can occur with significant frequency.
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Relatively common.
Note:
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