The Journal of Bone and Joint Surgery

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IMAGE QUIZ ARCHIVE

Image Quiz
A Painful Mass in an Adolescent Boy (continued)
Answer: High-grade osteosarcoma of the humerus.
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Fig. 1	Fig. 2-A
Fig. 2-B	Fig. 2-C
Fig. 1 Plain anteroposterior radiograph of the shoulder and the humerus, showing evidence of a destructive lesion. Figs. 2-A through 2-C Findings on magnetic resonance imaging of the shoulder. Fig. 2-A Fat-suppressed T2-weighted coronal magnetic resonance image of the involved humerus. Fig. 2-B Fat-suppressed T2-weighted transaxial magnetic resonance imaging scan in the region of the lesion, demonstrating evidence of soft-tissue and osseous extension. Fig. 2-C T1-weighted coronal (left) and fat-suppressed T2-weighted sagittal (right) magnetic resonance images of the entire humerus, demonstrating the intramedullary extent of the tumor and its proximity to the olecranon fossa.
After a course of neoadjuvant chemotherapy, the lesion was treated surgically with wide resection of the entire humerus (Figs. 3 and 4).
Fig. 3	Fig. 3 Morphologic cut section of the pathology specimen, demonstrating the lesion and the extent of involvement. For larger view, click on image
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Fig. 4-A	Fig. 4-B
Fig. 4-C	Fig. 4-D
Figs. 4-A through 4-D Photomicrographic study of the lesion. Fig. 4-A Photomicrograph demonstrating the osteoid production (hematoxylin and eosin, ×10). Fig. 4-B Photomicrograph demonstrating the high mitotic activity (hematoxylin and eosin, ×60). Fig. 4-C High-power photomicrograph demonstrating the osteoid production (hematoxylin and eosin, ×40). Fig. 4-D Photomicrograph demonstrating chondroblastic differentiation (hematoxylin and eosin, ×20).
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Fig. 5-A	Fig. 5-B
Fig. 5 through Fig. 7 Shoulder hemiarthroplasty and total elbow arthroplasty with a total humeral replacement prosthesis were used to reconstruct the limb. Figs. 5-A and 5-B Intraoperative photographs of the resected humerus with the endoprosthesis for segmental replacement kept by the side for comparison.
Fig. 6	Fig. 6 Intraoperative photograph showing the surgical wound with the entire endoprosthetic humerus in place and the polypropylene mesh repair for the proximal end. For larger view, click on image
Figs. 7-A and 7-B	Figs. 7-A and 7-B Plain radiographs of the right humerus four-months after surgery, demonstrating the prosthesis. For larger view, click on image
Discussion
Osteosarcoma is defined as a malignant mesenchymal tumor in which the cancerous cells produce bone matrix. It occurs most commonly in adolescents and tends to occur with equal frequency in males and females. Although lesions can arise in any bone, conventional osteosarcoma has a predilection for the metaphyseal portion of the long bones, specifically the distal aspect of the femur and the proximal portion of the tibia¹. The proximal part of the humerus is the third most common site for this tumor², and a lesion at this site is associated with a poorer prognosis than that associated with lesions about the knee³. Patients usually present with pain and a firm, enlarging mass.
Macroscopically, the tumor presents as a heterogeneous mass that may contain large areas of new woven bone formation with prominent hemorrhage and necrosis within the tumor. Cartilaginous matrix is also laid down frequently by the tumor, which may appear blue-gray and lobulated.
Histologically, a conventional osteosarcoma is composed of neoplastic osteoblasts that are typified by marked pleomorphism. The cells vary in size and shape, the nuclei are hyperchromatic, and mitoses are frequent. The defining feature of these sarcomas is their property of producing an osteoid matrix that is often referred to as "malignant osteoid."
The radiographic features of osteosarcoma are those of an aggressive, destructive, permeative bone-producing lesion. The aggressive, destructive areas are characterized by radiolucency, showing a ragged, poorly marginated edge that rapidly destroys the overlying cortices and penetrates into the soft parts. At the sites of cortical penetration, an area of reactive bone (Codman's triangle) is frequently seen, while the advancing edge of the lesion is not contained by reactive bone. On magnetic resonance imaging, these tumors typically show low signal intensity on T1-weighted images and heterogeneous high signal intensity on T2-weighted images in the medullary cavity and an associated soft-tissue mass.
The mainstay of treatment of osteosarcoma is wide resection with chemotherapy as an adjunct. Preoperative, neoadjuvant chemotherapy can facilitate tumor necrosis and shrinkage and can help to ensure complete resection of the tumor at the time of surgery. On occasion, lesions of the proximal portion of the humerus can have an extensive extraskeletal component, making limb-salvage surgery difficult. However, approximately 80% of osteosarcomas of the proximal part of the humerus can be treated by a limb-sparing resection³.
Formal endoprosthetic reconstruction of the humerus following tumor resection has been described in several series and case reports^4-7. The main advantage with endoprosthetic reconstruction is to maintain adequate humeral stability, specifically at the glenohumeral joint, and to preserve length and proper shoulder contour. Total humeral endoprosthetic reconstruction, the treatment option employed in this patient, has been reported less frequently. The entire humerus is replaced by a prosthesis that is coupled with elbow and shoulder joint reconstruction. Although shoulder and elbow range of motion is less than optimal following this procedure, the functional and psychological benefits have been found to be superior to those achieved after forequarter amputation³. In this patient, the tumor extended distally in the medullary canal to a point close to the olecranon fossa, precluding any possibility of a proximal humeral prosthesis and necessitating resection and reconstruction of the entire humerus, including the elbow joint.
The definitive surgical management of such a lesion should be decided after careful consideration of the extent of tumor invasion, surgical risk, functional outcome, and the potential for long-term survival.
*In support of their research or preparation of this manuscript, one or more of the authors received grants or outside funding from Stryker. None of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
References
1. Dahlin DC, Coventry MB. Osteogenic sarcoma. A study of six hundred cases. J Bone Joint Surg Am. 1967;49:101-10. 2. Sim FH, Pritchard DJ, Ivins JC. Forequarter amputation. Orthop Clin North Am. 1977;8:921-31. 3. Malawer MM. Tumors of the shoulder girdle. Technique of resection and description of a surgical classification. Orthop Clin North Am. 1991;22:7-35. 4. Ham SJ, Hoekstra HJ, Eisma WH, Schraffordt Koops H, Oldhoff J. The Tikhoff-Linberg procedure in the treatment of sarcomas of the shoulder girdle. J Surg Oncol. 1993;53:71-7. 5. O'Connor MI, Sim FH, Chao EY. Limb salvage for neoplasms of the shoulder girdle. Intermediate reconstructive and functional results. J Bone Joint Surg Am. 1996;78:1872-88. 6. Grimer RJ, Carter SR, Sneath RS. Management of a huge tumour of the humerus by total replacement of the humerus: an 11-year follow-up. Arch Orthop Trauma Surg. 1998;117:298-9. 7. Yoshimoto S, Kaneso H, Tatematsu M. Total prosthetic replacement of a humerus for chronic osteomyelitis with a pathological fracture. Report of a case. J Bone Joint Surg Br. 1977;59:360-2.