Kitakanto Med J
2004 ; 54 : 147-151
147
Giant Cell-Rich Osteosarcoma Simulating
Giant Cell Tumor of Bone
Tetsuya Shinozaki,1 Toshio Fukuda,2 Hideomi Watanabe,1
and Kenji Takagishi1
A seventeen-year-old boy was referred to our hospital, complaining of continuous pain of his left wrist
joint. Plain roentgenogram showed an osteolytic lesion at the distal end of the radius. An operation
in which the tumor was curetted was performed suspecting giant cell tumor. Pathological diagnosis was
of a giant cell tumor. One month after the operation, radiological findings showed local recurrence with
an expanded lysis. Wide resection of this tumor followed by a vascularized fibular graft was performed.
Six months after the second operation, soft part swelling suggesting local recurrence was again prominent.
Upper arm amputation was performed because of the bad local condition. The pathological diagnosis
of these operative specimens was of giant cell tumor similar to that of the initial specimen. Multiple
metastases appeared eight months after the third operation. In spite of intensive treatment, the patient
died of respiratory failure. Autopsy revealed that pathological features from metastatic specimens were
similar to those of osteosarcoma, not giant cell tumor. When we encounter patients presenting with a
giant cell tumor, especially when they are younger than the age at which such lesions usually occur, we
should bear in mind the possibility of an osteosarcoma and perform intensive chemotherapy and surgery.
(Kitakanto Med J 2004 ; 54 : 147•`151)
Key words : giant cell tumor, osteosarcoma, autopsy, clinical diagnosis, surgical treatment
Introduction
Giant cell tumor of bone comprises a characteristic
mixture of varying numbers of multinucleated giant
cells dispersed in mononuclear stromal cells.L2 Its
pathological features are utilized to assess clinical
behavior.' However, the prognostic significance of
histological grading remains controversial.4•`6 More-
over, local aggressiveness on clinical or radiological
grounds cannot be correlated with any specific find-
ings.4,6 Metastases are rare events : pulmonary metas-
tases have been reported in less than 5 % of patients
with conventional giant cell tumor of bone.5•`8 It is
sometimes stressful for clinicians to decide how to treat
giant cell tumor of bone.
Giant cell-rich osteosarcoma is a rare tumor
subtype accounting for only 1 - 2 % of all osteosar-
comas.9,10 Incorrect histological diagnosis as a giant
cell tumor may be made because of similarities between
these tumors. Clinical information including the
prognosis and optical treatment is limited.10 This report describes a case of rare giant cell-rich osteosar-coma with an aggressive clinical course and rapidly
fatal outcome.
Case Report
A seventeen-year-old boy was referred to our hospi-tal on August 1991 complaining of continuous pain of his left wrist joint. He had initially noted the pain in
May 1991 while playing volleyball. On physical
examination, his wrist joint showed severe swelling with local heat and tenderness ; the range of motion of
his left wrist joint was slightly limited. Laboratory data showed only a slightly elevated serum alkaline
phosphatase activity. Plain roentgenogram showed an osteolytic lesion at the distal end of the radius (Fig. 1). Arteriography demonstrated hypervascularity at
that area. An operation by which the tumor was
1 Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine 2 Department of Laboratory Sciences
& Pathology, Gunma University School of Health Sciences
Received : December 12, 2003
Address : TETSUYA SHINOZAKI Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, 3-39-22
Showa Maebashi, Gunma, 371-8511 JAPAN
148 Giant Cell-Rich Osteosarcomas
curetted was performed in August 1991. Investiga-
tions of other lesions, such as bone or extraskeletal metastases, were not performed at that time because
giant cell tumor was suspected because of clinical and radiological findings. Pathological diagnosis was
indeed of a giant cell tumor with spindle-shaped or ovoid-shaped stromal cells, a few mitotic figures and
osteoclastic type giant cells (Fig. 2). In September 1991, radiological findings of his left wrist joint showed local recurrence with an expanded lysis and
loss of the sclerotic margin (Fig. 3). Wide resection of
this tumor followed by a vascularized fibular graft with fusion of the left wrist joint was performed in
October 1991. Pathological findings were similar to those at the time of the initial operation. However, in April 1992, soft part swelling suggesting local recur-rence was again prominent (Fig. 4). We consulted
pathologists to confirm that pathological findings were truly compatible with those of giant cell tumor because
this local recurrence was unexpectedly early. They unanimously replied that thesefindings were compat-
ible with those of giant cell tumor, not those of osteosarcoma. Because of deterioration in the clinical
findings, we started chemotherapy using pirarubicin, ifosfamide and carboplatin ; despite that treatment, local swelling worsened with severe pain. Upper arm
amputation was performed in September 1992 because of the bad local condition. Pathological findings
were similar to those of the previous two operations. In December 1992, the patient complained of low back
pain. Plain roentgenography showed a compression fracture of the third lumbar vertebral body. Chest
roentgenography also showed pulmonary metastasis at that time. In June 1993, the patient became unable to walk because of spinal cord palsy below the level of
Fig. 1 Plain roentgenogram of the left distal radius at the time
of presentation in August 1991. The arrow indicates the
osteolytic lesion.
Fig. 2 Operative specimen, taken in August 1991, showing
spindle-shaped or ovoid-shaped stromal cells with a few
mitotic figures and osteoclastic type giant cells (HE, •~
50).
Fig. 3 Plain roentgenogram showing local recurrence with
expanded lytic lesion and loss of the sclerotic margin
(arrow) in September 1991.
149
the tenth thoracic spine. Radiation therapy, total 50
Gy, was administered to the lumbar spine in June 1993.
In October 1993, 99mTc-DMSA scintigraphy" showed
increased uptake at skull, sternum, cervical spine, thor-
acic spine, lumbar spine, and pelvis. Chemotherapy
using high-dose methotrexate, cisplatin and ifosfamide
was continued ; little effect was obtained. The
patient died in January 1995 of respiratory failure. At autopsy, metastases were found in the bilateral upper
pulmonary lobes and posterior thoracic walls, thoracic and lumbar spines, sacral bone, lumbar spinal cord,
and skull. Metastases of the lung and posterior pul-
monary walls included hemorrhagic foci and ossifica-
tions. The metastases comprised multinucleated giant
cells interspersed with spindle-shaped stromal cells
showing a compact or striform pattern with a few
mitoses. Little atypism of the stromal cells differed
from that of the operative specimens. However,
tumorous osteoid formation was prominent compared
with that of the operative specimens, especially in
pulmonary and thoracic wall metastases (Fig. 5). They also showed a telangiectatic and hemangio-
pericytoma-like pattern. Considering these findings from the autopsy specimens, the final pathological diagnosis was giant cell-rich osteosarcoma.
Discussion
Osteosarcomas are composed of heterogeneous cell
populations including giant cells.12 Whereas reports
of giant cell-rich types are fewa) because of histological
similarity, it is often difficult to differentiate from
benign or malignant GCT.9 Radiological findings
including tumor location and histological characteris-
tics such as anaplasia of stromal cells and osteoid
formation can assist in making a definite diagnosis.9
However, clinical features are important to make the
correct diagnosis.
In our case, the radiological finding presenting an
osteolytic lesion that was typical of a giant cell tumor.
As we mentioned above, recurrence was noted only a
couple of months after initial surgical treatment
because curettage was performed alone.1,2 Expecting
local control, we tried wide resection with reconstruc-
tion of the wrist using a vascularized fibular autograft.
However, several months after the second surgery,
roentgenography showed soft part swelling suggesting
local recurrence again. Locally aggressive disease and
multiple recurrences appear to be risk factors for
pulmonary metastases in benign giant cell tumor of bone.7 Further, local recurrence and the primary
lesion at the distal radius seem to be associated with an
increased risk of lung metastases.13 Patients of a giant
cell tumor with lung metastases had favorable progno-
sis independent on the type of treatment used7,8,13
because spontaneous regression was reported.8,13,14
However, we initiated chemotherapy using pirarubicin,
ifosfamide, and carboplatin because we suspected that
this aggressive radiological finding might show a
Fig. 4 Plain roentgenogram showing prominent soft part swell-
ing (arrow) in July 1992.
Fig. 5 Autopsy specimen, taken from the right thorax in Janu-
ary 1995, showing spindle-shaped stromal cells with a few
mitotic figures and osteoclastic type giant cells. Tumor-
ous osteoid formation was prominent (HE, •~ 75).
150 Giant Cell-Rich Osteosarcomas
malignant bone tumor such as osteosarcoma. How-
ever, when we consulted pathologists about pathologi-
cal features of operation specimens, they replied consis-
tently that the features were characteristic of a conven-
tional giant cell tumor, not osteosarcoma or malignant
giant cell tumor. In spite of the intensive chemother-apy and radiation therapy, the patient died of progres-
sive metastases. Autopsy revealed that pathological
features from the metastatic lesions showing tumorous
osteoid formation were similar to those of osteosar-
coma, not giant cell tumor. Malignant transforma-
tion of giant cell tumor is less likely because the
malignant transformation of the formerly conventional
lesion should take many years without prior history
such as local irradiation. It is rare to find patients
younger than age 20 with malignant transformation.5 Differential diagnosis between giant cell-rich osteosar-
coma and benign and malignant giant cell tumor is
controversial even though histological findings such as
tumor osteoid formation and anaplasia of the
osteoclast-like giant cells were reported to be impor-
tant for the diagnosis of osteosarcoma.5,9 Malignant
giant cell tumor never produces tumor osteoid, bone,
or cartilage in the manner that an osteosarcoma does.
Bizarre giant cell forms are found with osteosarcoma,
but the anaplastic nuclei are usually multilobulated,
unlike the multinucleated osteoclast-like giant cells
that characterize malignant giant cell tumors.5 Clini-
cal features of the tumor location such as metaphyseal
or diaphyseal centering and the existence of radiogra-
phic Codman's triangle, intralesional fluffs, cortical ballooning, and faint onion-skin-like periosteal reac-
tion also aid osteosarcoma diagnosis.5,9,10 Malignant
giant cell tumor usually occurs in patients of advanced age, i.e., over 60 years, whereas most conventional
giant cell tumors occur in patients of 20-50 years old.5 This case reports a seventeen-year-old patient. The
tumor located in the epimetaphysis to epiphysis.
Cortical ballooning was seen radiographically,
although small Codman's triangle and intralesional
fluffs were apparent. Tumor osseous tissue produc-
tion could be seen in metastatic lesions. Radiation-
induced sarcomatous change can be excluded because
of the short duration after radiation therapy15 and
occurrence out of the irradiated areas. Based on these
findings, the final diagnosis was a giant-cell-rich
osteosarcoma.
Clinical features of the case provide clues to differ-
entiating giant cell-rich osteosarcoma from the giant
cell tumor of bone, a relatively common neoplasm
occurring in the epiphyseal regions of patients of 20-40
years.2,16 When we meet patients presenting with
giant cell tumor in terms of radiological and his-
tological findings, especially when they are younger
than the age at which giant cell tumor usually occurs,
we should bear in mind giant cell-rich osteosarcoma
and perform intensive chemotherapy and surgery.
Acknowledgments
We are grateful to Drs. Yokoo Hideaki, First
Department of Pathology, Gunma University Faculty
of Medicine, and Rikuo Machinami, Department of
Pathology, Kawakita General Hospital for their valu-
able discussions regarding pathological diagnosis.
We thank Professor Kenneth P.H. Pritzker, Depart-
ment of Pathology and Laboratory Medicine, Univer-
sity of Toronto, for his valuable suggestions. We also
thank Mr. Kiichi Osawa for his technical assistance in
making the figures.
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