4. Primary Central Chondrosarcoma
The primary or central conventional chondosarcoma is a low
grade but malignant cartilagenous tumor found typically in adults
between the ages of 30 and 60 years. The tumor arises from the
medullary canal of a large bone such as the pelvis, femur, tibia or
proximal humerus. Because the tumor is slow growing, there is
little symptomatology and the tumor frequently becomes quite
sizable before a physician is consulted. Primary chondrosarcoma
is extremely rare in small bones of the hand or foot. The meta-
physeal portion of a long bone is the most common location
although diaphyseal locations are not unusual. 85% of central
chondrosarcomas are low grade lesions which on radiographic
examination demonstrate matrix calcification similar to that seen
in benign enhondromas, whereas the high grade chondrosarcomas,
which are rare, are frequently noncalcified and take on the
permeative appearance similar to other high grade sarcomas such
5. as fibrosarcoma and Ewing’s sarcoma. Histologically, the low
grade central chondrosarcoma has a fairly well differentiated
chondroid matrix like that of an enchondroma but shows evidence
of permeative invasion into the adjacent cortical and cancellous
structures. There is rarely any mitotic activity in the low grade
lesions. They have larger nuclear patterns with a higher degree
of atypicism compared to benign enchondromas.
These low grade tumors have a good prognosis in terms of a
low metastatic incidence to the lung but they must be treated
aggressively with a wide resection in order to prevent local
recurrence. One can not rely on adjuvant therapy such as radiation
or systemic chemotherapy because these low grade lesions are
notoriously resistant to adjuvant therapy.
6. CLASSIC Case #125
50 year female with chondrosarcoma prox humerus
225. Secondary Peripheral Chondrosarcoma
The vast majority of secondary peripheral chondrosarcomas arise
from a prexisting osteochondroma and do not occur before puberty.
These lesions tend to be slow growing with minimal to mild
symptoms. The most common site is the pelvis, followed by the
proximal femur, proximal humerus, and ribs. Plain radiographs show
a large calcifying mass on the surface of bone that measure over
5 cm in girth. When one sees an osteochondroma with a cartilagenous
cap over 3 cm in thichness, there is a strong likelihood for a
secondary chondrosarcoma. The overall prognosis for the secondary
peripheral chondrosarcoma is much better than that for the primary
central chondrosarcoma and usually requires only a simple wide
resection with little chance for local recurrence.
226. CLASSIC Case #126
exostosis
tumor
56 year male with 2ndary peripheral chondrosarcoma ilium
281. Dedifferentiated Chondrosarcoma
Of all the chondrosarcoma variants, by far the most malignant and
potentially fatal is the dedifferentiated chondrosarcoma that
accounts for approximately 5-10% of all chondrosarcomas. It
most likely arises as a result of a second mutation within a pre-
existing low to intermediate grade chondrosarcoma, resulting in
the formation of a malignant fibrous histiocytoma or osteo-
sarcoma immediately adjacent to the lower grade chondrosarcoma.
Histologically, the low and high grade portions of this tumor are
geographically separated by sharp margins. These tumors usually
occur in patients between the ages of 50 and 70 years in the
same areas where primary central chondrosarcomas are found:
the pelvis, femur and proximal humerus. The characteristic
radiographic appearance is that of a flocculated calcific lytic
lesion arising from the central area of bone with an adjacent area
with more extensive infiltration into the surrounding cortical bone.
282. There is no evidence of calcification in the high grade portion of the
lesion and it typically breaks through the cortex and into the
subperiosteal space.
The prognosis for this variant of chondrosarcomqa is extremely
poor, most patients dying from metastatic disease within one or two
years after the diagnosis is established. Adjavent chemotherapy or
radiation therapy is not very effective, mainly because of the older
age group in which the tumor occurs. The primary treatment
modality is wide surgical resection.
342. Clear Cell Chondrosarcoma
The clear cell chondrosarcoma is one of the rarest variants of the
chondrosarcoma. It is found more commonly in males than females
between the ages of 20 and 50 years. The most common location
for this tumor is in the femoral head. Radiographically the clear cell
chondrosarcoma has the appearance of a lytic lesion in the epiphysis,
similar to the chondroblastoma in a younger age group for which it
is frequently misdiagnosed. It has a geographic pattern with central
stippled calcification similar to that of a chondroblastoma. Histo-
locally it also has the appearance of a chondroblastoma with the
presence of benign macrophages and polyhedral stem cells with a
clear cell chicken wire appearance. But in some areas one will see
evidence of a low grade chondrosarcoma in which giant cells are not
seen, clearly separating it from the chondroblastoma.
The treatment for this condition consists of a wide resection which
in the femoral head would be a transcervical resection and replace-
343. ment with a bipolar prosthesis. If the lesion is treated by simple
curettement, the recurrence rate is quite high compared to the
chondroblastoma. The chance for pulmonary metastasis is very
unlikely and local recurrence is rare following a wide resection.
344. CLASSIC Case #128
25 year male with clear cell chondrosarcoma femoral head
358. Mesenchymal Chondrosarcoma
The mesenchymal chondrosarcoma is another rare variant of the
chondrosarcoma. It consists of low grade chondrosarcoma com-
ponents with an infiltration of primitive mesenchymal cells giving
it the histological appearance of a Ewing’s sarcoma or a hemangio-
pericytoma. It can be seen in soft tissue as well as bone in young
adults, more often in females. The most common location is in the
jaw, followed next by the spine or ribs, with a very few cases seen
in long bones. Because of the high grade component of this lesion,
it is treated as a high grade sarcoma with adjavent chemotherapy
and radiation therapy along with a wide resection if possible.
Despite this aggressive program of treatment, the prognosis is very
poor because of a high incidence of pulmonary metastases and
local recurrence.
359. CLASSIC
Case #129
34 year female
mesenchymal
chondrosarcoma tumor
LD spine & paraplegia
Sagittal MRI
