Untitled Document

CASE REPORT

Year : 2020  |  Volume : 3 |  Issue : 2 |  Page : 12-15 |  DOI : https://DOI-10.46319/RJMAHS.2020.v03i02.004

 

Intramedullary Chondrosarcoma of Proximal Humerus

Pavan Kolekar1, Gurushankar G2, Anand SH3

1 Postgraduate, 2 Professor and Head, 3 Associate Professor, Department of Radiology,
Sri Siddhartha Medical College & Research Centre, Tumakuru,
Sri Siddhartha Academy of Higher Education, Tumakuru.

DOI-10.46319/RJMAHS.2020.v03i02.004
Abstract
Chondrosarcoma is a malignant cartilage-forming tumour accounting for 8–17% of all biopsied primary bone tumours and 20–25% of all biopsied malignant bone tumours. It is classified as central if arising within medullary bone and peripheral if arising from the surface of bone. A30-year male presented with hard swelling and pain in the left shoulder region for 6 months. X-ray showed a well-defined lytic lesion in the proximal part of the humerus with chondroid matrix calcificationas ring-and-arc. Confirmation of the findings was done on CT scan. MRI shows a typical hyperintense multi-lobular pattern on fluid-sensitive sequences (T2 WI) with low signal intensity foci representing chondroid calcification on all pulse sequences. Radiological diagnosis was confirmed on histopathology.
Keywords: T1WI,T2WI, Axial, Coronal.

Introduction
Chondrosarcoma is a malignant tumour of chondrogenic origin that remains essentially cartilaginous throughout its evolution. It arises from chondroblasts and collagenoblasts, thus producing only cartilage and collagen. Chondrosarcoma is third most common primary malignant tumour of the bone in comparison with multiple myeloma and osteosarcoma, accounting for about 10% of all primary bone tumours. It usually develops later in life than osteosarcoma and carries a much better prognosis because metastases often occur late.
Chondrosarcoma can be divided into two broad categories which are: primary and secondary. A primary chondrosarcoma is believed to be malignant from the outset while a secondary chondrosarcoma arises in a pre-existing bony lesion, usually an enchondroma or an osteochondroma and rarely in chondromyxoid fibroma or chondroblastoma. A chondrosarcoma may also be classified according to its histological grade as low grade (45–50% of cases), myxoid (30–40% of cases), high grade (8–25% of cases) or dedifferentiated, which refers to the development of an adjacent high grade non-chondroid neoplasm, typically osteosarcoma or malignant fibrous histiocytoma. Other distinct varieties include mesenchymal and clear cell chondrosarcoma.


Case Report
Majority of the patients are above 50 years of age, with the peak incidence in the fifth to seventh decades. Secondary chondrosarcoma tends to present at a slightly younger age in the fourth and fifth decades. Our case study was a male aged 30 years, presented with pain and swelling over the left arm near the shoulder involving the proximal part of the humerus since 6 months which is gradually progressive in nature associated with restricted movements of left shoulder joint. On inspection, there was diffuse swelling over the left shoulder joint with loss of contour. On palpation, tenderness was present over the swelling, it was bony hard in consistency and fixed in nature measuring approximately 6 x 4 cm (length x breadth). Neoplastic musculoskeletal pathology was the clinical diagnosis. X-ray of the left shoulder showed an expansile, ill-defined, lytic lesion involving the cortex and medullary region of proximal shaft of humerus with chondroid calcification visible as ring and arc (Figures 1). It shows endosteal scalloping with periosteal new bone formation and adjacent soft tissue component. A helical multi-slice CT scan of 5 mm thickness was done at the site of interest. CT scan showed lytic expansile lesion with endosteal scalloping and cortical thinning in the proximal shaft of the humerus. It contains matrix calcification visible as ring and arc (Figure 2).
1
Figure 1: X-ray of left shoulder joint shows an expansile, ill-defined,lytic lesion involving the head of the humerus, neck and proximal shaft
2
Figure 2: Coronal CT image shows an ill-defined expansile, lytic lesion with endosteal scalloping and thinned out cortex involving the proximal shaft of humerus with calcific specks in surrounding soft tissue
3
Figure 3: Coronal T1WI shows an ill-defined lobulated mass which is showing low signal intensity with focal areas of hyperintensity due to trapped marrow
4
Figure 4: Axial T2WI shows hyperintense multi-lobulated mass with fibrous septae and calcification
5
Figure 5: Histopathology shows multiple chondrocytes in lacuna, nuclear pleomorphism, prominent nucleoli and calcification

On MRI, cartilage shows characteristic increased signal intensity on T2-weighted images and a multilobulated, septated appearance. The lesion is slightly iso to hypointense to muscle on T1-weighted images and may show focal areas of increased signal intensity due to trapped marrow. Left shoulder MRI was done on 1.5 Tesla SIEMENS ESSENZA and required standard sequences were taken in axial, coronal and sagittal planes. T1W MR image shows the large soft tissue component of the chondrosarcoma as a low signal intensity lobulated mass in the left shoulder region involving the proximal shaft of the humerus. The lesion was showing increased signal intensity on T2WI with low signal septae. The neurovascular bundle was not affected and the glenohumeral joint space was normal.
FNAC sample showed lobules of cartilage, hemorrhage and focal necrosis. Cartilage shows multiple chondrocytes in lacuna, nuclear pleomorphism, prominent nucleoli and calcification. No mitosis notes. According to histopathological staging, it is corresponding to low grade, stage I, extra compartmental.
Discussion
Chondrosarcoma is the third most common primary malignant bone tumor, after myeloma and osteosarcoma.[1] Primary chondrosarcoma occurs mainly between the ages of third and seventh decade of life. Patients usually present with painful tender swelling which shows a gradual progressive growth with an average duration of 1-2 years. [2]
Common sites
The pelvis, proximal femur and proximal humerus. Approximately 9% of chondrosarcomas occur in the ribs, making this the most common primary malignancy. Chondrosarcomas in the hands and feet are rare in contradiction to the high incidence of enchondromas at both these sites.
Imaging
The radiographic features of central chondrosarcoma are those of a lytic lesion, well-defined in low-grade cases and progressively increasingly ill-defined in higher-grade cases.[3,4] Most of the peripheral chondrosarcomas probably arise from benign osteochondromas. The distinction between active osteochondroma and low-grade chondrosarcoma can be extremely difficult. Radiologically, there may be destruction of part of a well-formed calcified cap or ossified stem of such a structure. The thickness of the cartilage cap cannot be assessed radiographically unless it abuts some other structure, e.g. a vessel or viscus filled with contrast medium. It can be readily identified by USG, CT or MRI and the thicker the cap, the more likely it is that malignant degeneration has supervened. Most osteochondromas have cartilage caps less than 5 mm thick and a cap in excess of 20 mm is likely to be malignant.[5]
Other Varieties of Chondrosarcoma
Mesenchymal chondrosarcoma[6] is an uncommon entity. It occurs typically in the spine or the nonpelvic flat bones and at a younger age as compared to the conventional chondrosarcomas. Histologically, it has a much more cellular malignant matrix than the conventional chondrosarcoma. Radiologically, it is indistinguishable from a central chondroid calcification. Local recurrence and disseminated metastases occur earlier and more frequently.
Clear cell chondrosarcomas[7] are low-grade chondrosarcomas with a long history. They almost always involve the ends of long bones (femur or humerus) after closure of the epiphyseal plate. Radiographically, they are usually lytic and may show a loculated or a “soap-bubble” appearance.
Conclusion
Chondrosarcomas if detected early, the prognosis can be much improved. The treatment is wide resection and prosthetic reconstruction if possible. The tumour shows a poor response to radiotherapy and cytotoxic drugs. Radiotherapy is an alternate treatment of choice to incomplete surgery. Follow-up can be done by plain films and MRI, even if the endo-prothesis may generate artifacts.
Financial support and sponsorship: Nil
Conflict of interest: Nil
References
1.     H. Gelderblom, P. C. W. Hogendoorn, S. D. Dijkstra et al., “The clinical approach towards chondrosarcoma”. The Oncologist. 2008; 13(3):320-329.
2.     K. Krishnan, Dahlin's Bone Tumors: General Aspects and Data on 11087 Cases, Lippincot-Raven Publishers, Philadelphia, Pa, USA, 5th edition, 1996.
3.     Murphey MD, Walker EA, Wilson AJ, et al. From the archives ofthe AFIP: imaging of primary chondrosarcoma: radiologic– pathologic correlation. Radiographics 2003;23(5):1245-78.
4.     Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. II. Chondrosarcoma. Skeletal Radiol 2012;42(5):611–26.
5.     Lee YK, Yao L Wirth CR. MR imaging of solitary osteochondromas: Report of eight cases. AJR. 1987;149:557-60.
6.     Nakashuma Y ,Unni KK, Shives TC, et al. Mesenchymal chondrosarcoma of bone and soft tissue. A review of 111 cases. Cancer. 1986;57:2444-53.
7.     Collins NS, Koyama T, Swee RG, et al. Clear cell chondrosarcoma: Radiographic, computed tomographic and magnetic resonance findings in 34 patients with pathologic correlation. Skeletal Radiol. 2003;32:687-94.
Address for Correspondence: Dr Pavan Kolekar, Postgraduate, Department of Radiology, Sri Siddhartha Medical College & Research Centre, Tumkur, Sri Siddhartha Academy of Higher Institution, Tumkur 572107. E-mail: kolekar.pavan@gmail.com


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