This document discusses neuronal cell tumors, which are rare but do exist. It provides examples of neuronal cell tumors like central neurocytomas that have been found in the brain. Key evidence that these tumors are of neuronal origin includes the expression of neuronal markers like neurofilaments and synaptophysin, as well as the presence of neuritic processes and synaptic vesicles in microscopic and electron microscopy images. While unusual given neurons' post-mitotic nature, some tumors seem to arise from neuronal cells based on their specialized neuronal features and characteristics.

1. NEURONAL CELL TUMORS

2. This course was a very useful tool as a
review of neurophysiolgy. I wish that my
teachers would have explained these complex
processes as clear as I saw them in this
course.

3. These classes also awoke my curiosity
about neuronal neoplasms. During the
course we were told that there are not
neuronal tumors, but in the laboratory
there are reported cases of neuronal
neoplasms. Some characteristics that
they display have convinced some of us
that they are really of neuronal nature.

4. I chose this topic because I think that it
can be an interesting and controversial
issue for us all, and we all can discuss
and learn a lot one from the others. I will
wait your comments and new information
that you would like to add to this little
discussion.

5. Before we start with the main issue of
this final project, I only want to make a
quick review of the principal cells of the
central nervous system: The neurons an
the glia.

6. The neuron is the functional unit of the
nervous system. It’s an electrically,
excitable cell that transmits information
through electrical and chemical signs in
the central and peripheral nervous
system. They allow us to think, to use our
five senses, to move, etc.

7. And as for the glial cells, they are more
numerous than neurons. They retain the
capacity to proliferate. They mantain the
brain homeostasis, form myelin and
provide support and protection for the
neurons.

8. With this information in mind, now we will make a rapid
review of the structure of a neuron. Neurons have typically a
soma or cell body, with multiple projections from the soma
that consitute the dendrites, where the information is
received, and a long axon, that ends up in the synaptic
terminal. The axon transmits the impulse outside of the
neuron.

9. As all the cells of the body, the neurons have
inside of them a nucleus as well other
organelles, like reticulum endoplasmic,
mitochondria and golgi apparatus.

10. But every cell of the body has some
particular features that allow them to
function properly in the organ where
they are placed. We can identify these
specialized structures in order to
establish the nature of the cell.

11. Every cell of the body needs filaments, some long proteins
that allow them to keep their shape and provide structural
support. In the case of neurons, these filaments are of a
specialized type and called neurofilaments. They also help in
the axonal transport. In this image the neurofilaments are
colored in green.

12. Neuronal cells also express
synaptophysin, a glycoprotein that is
present in the vesicles of the synaptic
terminal.

13. Using different methods in the laboratory,
we can establish the origin of a
neoplasm. Most of the neoplasms of the
central nervous system arise from the
glia, but a few of them seem to arise from
neuronal cells.

14. The neuronal cell tumors, also called
ganglionar cell tumors, use to come to
neurosurgical intervention within the
three decades of life. Commonly they are
localized in the supratentorial area.

15. Although defined by its neuronal
component, some of them are mixed with
glial elemements, and are consequently
called gangliogliomas. Those composed
purely of neuronal cells are called
gangliocytomas.

16. In the neuronal neoplasms, the ganglion
cells elabortae cytoplasmic processess
with the argyrophilia typical of axons on
neurohistochemical study, and also
contain parallel microtubular arrays and
clear presynaptic-type vesicles on
utrastuctural examination.

17. Although some tumors of glial lineage
sometimes asume neuronal cells
appearance, they manifest none of these
specialized features, characteristic of
neuronal cells.

18. Another important clue is to observe the
neoplastic alterations in the neuronal
cells, for example gigantism,
pleomorphism and multinucleation.
These make the difference with the glial
tunors that only have trapped neuronal
cells.

19. I will discuss only one example of these
rare neoplasms: The Central
Neurocytoma

20. The Central Neurocytoma is a rare tumor that
usually is located in the intraventicular system,
usually blocking the foramen of Monro. and for
the same reason produces symptoms and
signs of increased intracranial pressure. It
appears in young adults

21. In the MRI image we can aprecciate its
intraventricular location. The microscopic image
shows up some round cells embedded in a
delicate fibrillar matrix

22. This tumor is not agressive. Only needs
surgical resection. It is believed that it has a
neuronal origin because it expresses
synaptophysin, and neurofilaments in the
immunohistochemistry studies, and neuritic
processes replete with microtubules and
synsaptic-type vesicles in the electron
mycroscopy.

23. In this image we can appreciate the highly positive result for
synaptophysin. An antibody was used to target the
synaptophysin proteins that display a strong golden brown
color.

24. The findings in
electron microscopy
show up clear synaptic
vesicles.

25. All these findings led some of us to believe in
a neuronal origin. It’s weird, because we know
that neuron cells do not divide after birth, but
medicine is not an exact science like
mathematics. I’m looking forward for your
comments.
I also give thanks for this awesome course,
and I specially give thanks to God for all the
marvelous things that He prepared for us
when He designed our body.

26. Ackerman’s Surgical pathology, Juan Rosai 8th.
Edition, pages 2303-2308
Histology and Cell Biology, an Introduction to
Pathology, Kierszenbaum, 3th edition, pages 229-
234
BIBLIOGRAPHY

27. THANKS