Osteosarcoma of the rib
1 Department of Biomedical Imaging, Faculty of
Medicine, University of Malaya, Kuala Lumpur, Malaysia
2 Department of Surgery, Faculty of
Medicine, University of Malaya, Kuala Lumpur, Malaysia
This case describes the radiological-surgical correlation
of a rare case of osteosarcoma of the rib in a 15-year-old boy. Successful
repair of his chest wall defect using a wire mesh following extensive surgical
resection of the tumour is highlighted, such a procedure being the first
instituted at our centre. � 2008 Biomedical Imaging and Intervention
Journal. All rights reserved.
Keywords: Osteosarcoma, rib
All chest wall tumours in the paediatric population must
be assumed to be malignant. The differential diagnoses include Ewings sarcoma,
rhabdomyosarcoma, chondrosarcoma, primitive neuroectodermal tumours (PNET) or
Askin tumours, other sarcomas and metastatic lesions in the ribs. Osteosarcoma
occurs principally in the long bones while Ewings sarcoma is frequently seen in
flat bones like the ribs and pelvic bones. Osteosarcoma occurring as a primary
tumour in the rib is rare [1, 2]. This paper describes a rare case of
osteosarcoma of the rib in a 15-year-old boy, its imaging features and surgical
A 15-year-old Chinese boy presented with left-sided chest
pain, loss of appetite and weight, and low grade fever for 6 weeks followed by
cough and shortness of breath for a week prior to admission. On examination, he
was pale and febrile with a temperature of 38.5�C. Examination of his chest
revealed reduction of chest movement on the left side with reduced air entry
into the left lung. There were no masses palpable. Haematological investigation
revealed haemoglobin of 8.0 g/dL and a normal white cell count. Other blood
investigations were unremarkable. A chest radiograph showed a large pleural
mass in the left hemithorax, with rib destruction and a pleural effusion but no
significant shift of midline structures (Figure 1). A CT examination of the chest
showed a large heterogenously enhancing mass arising from left chest wall with
lytic destruction of the fourth rib and coarse calcifications. There was a left
pleural effusion with underlying lung collapse consolidation. There were no
lung nodules in the right lung to suggest metastases (Figure 2). Due to the
presence of calcifications in the tumour, a provisional diagnosis of osteogenic
sarcoma with a differential diagnosis of chondrosarcoma was made. Pleural
aspirate yielded bloody exudate. Cytology was negative and culture of the
aspirate showed no growth. A tru-cut biopsy of the mass revealed osteogenic
sarcoma. Histopathology findings showed a cellular tumour composed of diffuse
sheets of cells with pleomorphic nuclei and basophilic cytoplasm with presence
of multinucleated cells with mitotic figures. There were also areas of
calcification and osteoid formation. This was in keeping with a tumour
originating from the bone.
He underwent three cycles of chemotherapy.
Post-chemotherapy CT examination for assessment showed reduction of pleural
effusion but insignificant improvement in the tumour size. He was commenced on
second-line chemotherapy for sarcoma consisting of Ifosfamide and Etoposide and
completed two cycles. A CT examination done after completion of this
chemotherapy regime again showed no significant reduction in tumour size. A
decision was made for surgical excision of the tumour. At surgery, a necrotic
tumour mass measuring 9 cm by 13 cm in size arising from the antero-lateral
region of the left chest wall and surrounded by thickened pleura was found
extended from the third to the seventh intercostal spaces. It was adherent to
the left hemidiaphragm and causing significant compression of the left lung.
The third to seventh ribs on the left side was resected en bloc followed by
total clearance of associated necrotic tissue and diseased pleura. A left
thoracoplasty and reconstruction of the affected chest wall defect using a
titanium mesh was done (Figure 3). He recovered well from the surgery. There
was no further chemotherapy given to the patient after surgery. A CT
examination done 3 months later showed deformity of the left chest wall and the
titanium mesh in situ (Figure 4). There was no evidence of tumour recurrence,
pleural effusion, enlarged mediastinal nodes or focal lung lesions. The patient
remained well ten months after surgery.
Osteosarcoma and Ewings sarcoma make up the large majority
of pediatric bone tumours. Whilst osteosarcoma occurs principally in the long
bones, Ewings sarcoma is frequently seen in flat bones like the ribs and pelvic
bones. Osteosarcoma occurring as a primary tumour in the ribs is rare [1, 2]
although a few cases of osteosarcoma arising as metastatic involvement in the
ribs have been reported .
The peak incidence of osteosarcoma is in the second decade
of life with another peak occurring in older individuals after radiation or
Paget's disease. Burt et al found the majority of chest wall sarcomas were
related to previous irradiation to the chest . A few recent cases of
osteosarcoma of the rib have been reported in older children ranging from 7 to
13 years of age [1, 2, 4, 5]. The youngest patient with osteosarcoma of the rib
reported in the literature to this date is a 7-year-old girl . Our patient
is a 15-year-old adolescent. Histology studies showed the majority of the
tumours were of the highly malignant type. Extremely well differentiated
osteosarcoma has been reported occurring in the rib of a 45-year-old female
. It appears that the more malignant type of osteosarcoma occurs in younger
The commonest presentation of osteosarcoma of the rib is
pain and a palpable chest wall mass. The condition poses a significant
diagnostic challenge. The lesion is usually detected on a chest radiograph as a
soft tissue mass. Periosteal reaction, rib destruction and calcifications
within the mass may be difficult to visualise and assess, given the limitations
of a chest radiograph compared to the site of the tumour if it were in a long
bone. CT examination is useful for identification and characterisation of the
mass. Often, the epicentre of the mass can be localised to the rib. Invasion to
deeper structures like the muscles, pleura and lungs can also be accurately
assessed. Magnetic resonance imaging (MRI) may not offer any additional
information for definitive management as it is a tumour originating from the
bone, thus CT would be a more cost effective modality for evaluating the
tumour. This was proven true in this case where CT determined poor response to
chemotherapy while assessment of involvement of deeper structures allowed the
surgeons to plan the operation. In a case of osteosarcoma in a posterior rib
with involvement of the lumbar muscles of the back, MRI was used to assess
involvement of the spinal canal .
Osteosarcoma is derived from primitive bone-forming
mesenchymal stem cells and most often occur near the metaphyseal portion of the
long bones . The histologic subtypes of osteosarcoma described in the
literature include the parosteal, periosteal, well-differentiated
intramedullary, fibroblastic, osteoblastic and fibrosarcomatous types . For
osteoasarcoma of the rib, a wide surgical excision followed by adjuvant
chemotherapy increases the chance of a relapse-free survival of the patient
. Surgery should include resection of the full thickness of the chest wall
with wide margins that may include the adjacent ribs, intercostal muscles,
pleura and vertebrae. Large chest wall defects after resection may require
tissue flaps or mesh materials. In a review of surgical treatment of many types
of primary chest wall tumours in 41 patients by Athanassiadi K et al., the
majority had surgical treatment consisting of wide resection with the use of
synthetic mesh in 5 patients . Marlex and metal meshes have been used for
this purpose. The disadvantage of the metal mesh material is fragmentation over
several months while the Marlex mesh often results in non-contouring of the
material, producing compromised ipsilateral pleural space with the possibility
of compromised pulmonary function . The surgeons decided to use a titanium
mesh, which is usually used in neurosurgical procedures in the skull, because
of the good contouring properties of this material. In this case, the titanium
mesh was used successfully for the first time in the authors' institution for a
surgery of this kind.
Postoperative multi-agent chemotherapy has improved these
patients' survival, reducing the risk of both local and distant relapse.
However, there are also reviews which report no apparent difference between the
patients treated with surgery alone and those treated with both surgery and
chemotherapy. Overall survival despite modern adjuvant chemotherapy is noted to
be 27% at 5 years . Osteosarcoma of the flat bones are rarely associated
with metastasis in contrast to osteosarcoma at other sites . In this
patient, despite the large tumour mass with aggressive features on imaging and
poor response to chemotherapy, there was no evidence of metastases.
In summary, this paper presents a rare case of primary
osteosarcoma of the rib and emphasise that this condition should be considered
in the differential diagnoses of children and adolescents presenting with a
chest wall tumour. As metastases at presentation is uncommon, early diagnosis
and aggressive surgical management will help to improve outcome. CT remains the
essential imaging modality for accurate primary evaluation of the tumour mass,
identification of metastatic disease, evaluation of tumour response to chemotherapy
and postoperative evaluation of recurrent neoplasm, all of which have important
Figure 1 Chest radiograph showing a large pleural-based mass in the left hemithorax (arrows), with underlying rib destruction and a pleural effusion.
Figure 2 A contrast enhanced CT examination of the chest showing a large heterogenously enhancing solid mass arising from the skeletal chest wall with lytic destruction of the rib and calcifications (arrows). There is a moderate-sized pleural effusion (block arrow) and underlying lung collapse and consolidation (star).
Figure 3 (a) Gross appearance of the resected chest wall and the tumour (b) Appearance of the surgical site after resection of the tumour showing the titanium mesh covering the chest wall defect.
Figure 4 CT examination of the chest post-chemotherapy and chest wall surgery showing deformity of the left chest wall at site of extensive rib resection. The titanium mesh is seen in situ (arrows). There is no evidence of tumour recurrence.
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|Received 29 April 2007; received in revised form 29 November
2007, accepted 9 December 2007
Correspondence: Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. Tel.: +603-79492069; Fax: +603-79581973; E-mail: email@example.com (Sazilah Ahmad Sarji).
Please cite as: Lim WY, Ahmad Sarji S, Yik YI, Ramanujam TM,
Osteosarcoma of the rib, Biomed Imaging Interv J 2008; 4(1):e7
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