CHORDOMA is a tumor that arises from cells that
were originally involved in the formation of the Skull and Axial
Skeleton (Spine) during the embryological development
of the affected individual. This embryological entity is known as the
"NOTOCHORD". CHORDOMAS are very rare primary bone tumors
(comprising less than 1% of CNS tumors) that can occur at almost any
point along the axis of the Spine from the Base of the Skull
to the Sacrum and Coccyx (tailbone).
The microscopic appearance of Chordoma cells, when examined by
the Neuropathologist, is rather benign. Despite some efforts
to classify them as "malignant" consequent to their location, invasive
nature, and recurrence rate, these tumors do not metastasize.
Nevertheless, Chordomas are considered to be very dangerous
Approximately 1/3 of Chordomas are located along the Clivus
(the centrally located bone that forms the Base of the Skull which is
located immediately in front of the Brainstem and behind the nasopharynx
(See Figures 1A & 1B). The Skull Base, the Vertebrae
and the Sacrococcygeal area (the bottom of the Spine) are
affected with equal frequency by Chordomas.
Most Chordomas occur sporadically among the population;
however, there are small groups of people who develop this
tumor as a result of a mutation inherited as an autosomal dominant
trait. For further information related to this unusual aspect, please
refer to the
U.S National Institutes of Health/National Cancer Institute website
devoted to issue.
ECCHORDOSIS PHYSALIPHORI is a term that refers to small,
well-circumscribed, gelatinous masses that are adherent to the Brain
Stem and are composed of notochordal remnants as well.
While it is recognized that Ecchordosis physaliphori seldom
progresses into Chordoma, there are some unusual circumstances
where Ecchordosis physaliphori becomes sufficiently large
to produce Brain Stem and Cranial Nerve compression and symptoms.
Ecchordosis physaliphori is a reported finding in approximately
2% of autopsy examinations, but Chordomas are quite rare.
Grossly, Chordomas are variable in size. They are soft,
gelatinous, smooth, or lobulated and are gray-white in color on their outer
surface (See Figure 2A.) Even though Chordomas usually are
slow-growing tumors, they are locally aggressive with a
tendency to infiltrate into adjacent tissues and organs. In spite of
modern treatment, local recurrence of this tumor results in local
destruction of vital neural structures which eventually is the cause of
death. Metastases are most uncommon.
Symptoms related to a Chordomas depend upon the location and
size of the tumor. The most common presenting symptoms
of an intracranial Chordoma are diplopia (double vision) and
headache. One half of all patients with Clival region Chordomas
develop Cranial Nerve palsies as result of direct
involvement by the tumor of the 3rd, 4th,
5th and 6th Cranial Nerves.(See Figures 1 & 2 as
examples of involvement of these Cranial Nerves.)
CT scan or MRI studies are the basic Neuroimaging studies
that are used to evaluate Chordomas. MRI Scans are very
helpful in demonstrating important anatomical information about the
extent of the tumor and its relationship to vital adjacent
structures. CT Scans are particularly useful in identifying
the extent of bone destruction of the Clivus. This tumor usually
appears as a well demarcated locally destructive lesion. All of this
information is imperative in planning the optimal surgical
The natural history of any particular Chordoma and the effectiveness
of the different kinds of therapy are not well defined consequent to the
rare incidence and slow-growing nature of Chordomas.
There are no current medical therapies available although
some research protocols are in clinical trial.
One such study
is evaluating the effectiveness of "Gleevec" (imatinib mesylate)
which has been shown to have some anti-tumor activity in Chordomas. To date,
chemotherapy has not been effective for Chordomas.
The extent of surgical removal of Chordomas depends on
the size and location of the tumor. As a rule, complete resection
of a Chordoma with wide removal of its "margins" is the treatment of
choice. Unfortunately radical excision of a Clivus Chordoma with
"clean margins" is not feasible without producing severe, if not
catastrophic, neurological deficits since the Chordoma usually
involves vital Cranial Nerves and Cerebral Vessels.
Smaller tumors with less extensive local invasion may be more amenable
to "radical resection" without producing major deficits. This type of
extensive resection is associated with a longer disease-free interval.
In most cases, however, subtotal excision is the only
option (usually due to location and proximity to vital and sensitive
anatomical structures.) The addition of Radiation Therapy can lengthen
the time to the tumor's inevitable recurrence. In Skull Base
Chordoma cases where Radiation Therapy is utilized without surgical
removal, only 50% can expect 10-year local control.
The use of Proton Beam Radiation Therapy
in the treatment of Chordoma has been of particular interest
for many years. Unfortunately, this too, has been shown to have
risk to vision.
Stereotactic Radiosurgery is an alternative form of Radiation
Therapy that is more available than Proton Beam and
may be the most effective
of any of these different radiation modalities in the treatment of
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This page last edited on 2/19