You are in: eMedicine Specialties > Orthopedic Surgery > NEOPLASMS ChondroblastomaArticle Last Updated: Jul 18, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Hannah D Morgan, MD, Consulting Staff, Connecticut Orthopaedic Specialists Hannah D Morgan is a member of the following medical societies: American Academy of Orthopaedic Surgeons and American Medical Association Coauthor(s): Timothy A Damron, MD, David G Murray Endowed Professor, Department of Orthopedic Surgery, Professor, Orthopedic Oncology and Adult Reconstruction, Vice Chair, Department of Orthopedics, State University of New York Upstate Medical University at Syracuse Editors: Howard A Chansky, MD, Associate Professor, Department of Orthopedics and Sports Medicine, University of Washington Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Sean P Scully, MD, PhD, Professor, Department of Orthopedics, University of Miami; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Harris Gellman, MD, Consulting Surgeon, Broward Hand Center, Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine Author and Editor Disclosure Synonyms and related keywords: CB, bone tumor, giant cell tumor, GCT, benign chondroblastoma, Codman's tumor, Codman tumor, bone-forming neoplasm, malignant chondroblastoma, aneurysmal bone cyst INTRODUCTIONSection 2 of 11
  BackgroundA chondroblastoma is a rare, usually benign, tumor of bone that accounts for approximately 1% of all bone tumors. In 1931, Codman classified it as a chondromatous variant of giant cell tumors, when he described these lesions in the proximal humerus.1 A decade later, Jaffe and Lichtenstein renamed the Codman tumor a benign chondroblastoma to emphasize the chondroblastic genesis of the lesion and to distinguish it from the classic giant cell tumor of bone.2 PathophysiologyVarious theories have been proposed concerning the origin of chondroblastomas. Mii and colleagues described the results of ultrastructural examination of chondroblastomas.3 Their studies showed subcellular, calcium-containing precipitates that are similar to those seen in chondrocytes. Based on these findings, the authors concluded that the tumors are of chondrogenic origin. Aigner and colleagues, however, noted the presence of osteoid matrix–containing type I collagen and the absence of true cartilage matrix production.4 They considered the term chondroblastoma to be a misnomer and believed that the tumor should be reclassified as a bone-forming neoplasm. Brien and colleagues compared the characteristics of chondroblastoma of bone to chondroblastoma of soft tissue, giant cell tumor of the tendon sheath (GCTTS), and pigmented villonodular synovitis (PVNS).5 On examination of about 15 examples of GCTTS and PVNS, large areas of chondroid differentiation were noted that could not be distinguished from chondroblastoma of bone by either histologic or electron microscopic features. The researchers theorized that chondroblastoma of bone stems from an intraosseous proliferation of tendon sheath cells that have a predilection for chondroid formation. While the exact etiology of chondroblastoma remains uncertain, the presentation, appropriate evaluation, and treatment of patients with the condition have been well described. FrequencyUnited StatesChondroblastoma accounts for approximately 1% of all bone tumors. InternationalInternational incidence is not reported in current literature. Mortality/MorbidityPatients with benign chondroblastoma may limit activities due to pain. Malignant chondroblastomas, which may occur many years after the original lesion (even in the absence of radiation), are extremely rare and are associated with a dismal prognosis. RaceNo racial predilection is recognized. SexThe male-to-female ratio is 2:1 in most series. AgeApproximately 92% of patients presenting with chondroblastoma are younger than 30 years. However, chondroblastomas have been reported to arise in patients as young as 2 years and as old as 83 years. In several large series, most patients were diagnosed in the second decade of life. CLINICALSection 3 of 11
HistoryPain is the most common presenting symptom. It typically is mild and gradually progressive and initially may be attributed to a minor injury. If the lesion is juxta-articular, the patient may complain of joint swelling or diminished range of motion. Usually, constitutional symptoms are lacking. In their series of 70 patients, Turcotte and colleagues found the average duration of symptoms in patients with chondroblastoma to be 20 months.6 PhysicalThe physical examination is remarkable for localized tenderness in most patients. Soft-tissue swelling, mass, or joint effusion is present in about 20% of cases. Muscular atrophy or decreased joint motion is less common. CausesNo risk factors are known for chondroblastoma. There have been reports of abnormalities in chromosomes 5 and 8, as well as of p53 mutations, in patients with chondroblastoma. Sjögren and colleagues performed cytogenetic analysis of benign and malignant cartilage tumors7, and while they observed no consistent karyotypic abnormalities, there were recurrent breakpoints seen at 2q35, 3q21-23, and 18q21. DIFFERENTIALSSection 4 of 11
Chondromyxoid Fibroma Chondrosarcoma Giant Cell Tumor Other Problems to Be ConsideredChondromyxoid fibromas, which are found in patients in the same age group in which chondroblastomas are found, may mimic the latter radiographically and microscopically. Both types of lesions tend to have well-circumscribed lytic areas on radiographs, microscopically seen areas of immature cartilage and giant cells, and perilesional marrow edema on magnetic resonance imaging (MRI) examination. However, chondromyxoid fibromas most often arise from the metaphysis or metadiaphysis rather than from the epiphysis (where 90% of chondroblastomas are located), are devoid of calcification, and have a characteristic myxoid, pseudolobular pattern of organization, as well as more pleomorphic stellate cells. Giant cell tumors of bone also may mimic chondroblastoma, as the epiphyseal location and histologic characteristics can be quite similar. However, the former are almost exclusively seen in patients who are skeletally mature, while chondroblastoma tends to arise in skeletally immature patients. Furthermore, the epicenter of a giant cell tumor lies within the metaphysis. On histologic examination, giant cell tumors have elongated cells that are clustered together, in contrast to the round or polygonal cells of chondroblastoma. Calcifications and chondroid matrix also are absent in giant cell tumors. Eosinophilic granuloma is a lesion found in young patients that may appear in rare instances as a radiolucent epiphyseal lesion similar to chondroblastoma. However, microscopic examination reveals a more heterogeneous collection of cells, including histiocytes, granulocytes, and eosinophils. Finally, clear cell chondrosarcoma may have features that overlap those of chondroblastoma, but the presence of large cells with abundant clear cytoplasm and vesicular nuclei, as well as type II collagen and malignant chondrocytes, should distinguish this tumor. Typically, clear cell chondrosarcoma is an epiphyseal tumor of adulthood. WORKUPSection 5 of 11
Lab Studies
Imaging Studies
Procedures
Histologic FindingsChondroblastomas are lobulated tumors that consist of grayish-pink soft tissue intermixed with bluish chondroid tissue and calcifications. The lesions may have many hemorrhagic cystic areas. The tumors are composed of sheets of neoplastic mononuclear chondroblasts with eosinophilic cytoplasm and grooved nuclei (see Image 5). Interspersed among the mononuclear cells are osteoclastlike giant cells. The chondroid matrix typically is pink; on rare occasions, the basophilic matrix seen in hyaline cartilage is present. Some chondroblastomas may have a spindle-cell component, which represents either spindle-shaped mononuclear cells or reparative cells of fibroblastic origin. One of the most characteristic findings in the histologic examination of chondroblastomas is linear deposition of calcification surrounding individual chondroblasts, creating a chicken-wire pattern (see Image 6). Calcification may be so extensive that the chondrocytes in the area are not viable. In sections with well-preserved chondroblasts, mitoses may be seen, but atypical mitoses are not present in benign chondroblastoma. Cystic changes within chondroblastomas are common. Some represent secondary aneurysmal bone cysts, which are found in 20-25% of all patients with chondroblastomas. Other cysts are filled with serous fluid and are divided into unilocular or multilocular spaces. When these other cysts are present, the tumors are termed cystic chondroblastomas. Initially, there was concern that cystic chondroblastomas had a much higher recurrence rate than typical chondroblastomas, but later reports did not confirm this theory. Less frequently seen histologic findings are cellular atypia with enlargement and irregularity of chondroblast nuclei (occurring in 30% of cases); hemosiderin (in 25% of cases); surrounding cortical and soft-tissue permeation (in 5% of cases); myxoid areas (in 2% of cases); and vascular invasion (in 1% of cases). Immunostaining occasionally can be helpful in confirming the diagnosis of chondroblastoma. S-100 protein is strongly positive in the mononuclear cells, although it is absent in multinucleated giant cells and is present only focally in tumors with a large cystic component. Chondroblastomas are also positive for vimentin. Reticulin stain reveals a honeycomb pattern. TREATMENTSection 6 of 11
Medical CareRadiation therapy has been employed in the treatment of chondroblastoma but has essentially no current role in its treatment. Chemotherapy has not been reported in the condition's treatment. Surgical CareNo evidence suggests that chondroblastoma resolves spontaneously, so surgical treatment is indicated. The most common surgical procedure used for chondroblastoma is curettage, with or without autograft or allograft bone grafting. Other options, used less frequently, include substituting polymethylmethacrylate or fat implantation for bone graft, treating the curetted lesion with chemical cauterization (phenol), liquid nitrogen cryotherapy, marginal resection, and wide resection. ConsultationsAn orthopedic oncologist should manage large or recurrent chondroblastomas. DietNo dietary restrictions are necessary. ActivityUnless the lesion is particularly large and creates a risk of pathologic fracture, patients may participate in activity as tolerated. If an en bloc excision is performed, the patient's activity may be limited to protect the reconstruction. MEDICATIONSection 7 of 11
No medical therapy is available or reported for chondroblastoma. FOLLOW-UPSection 8 of 11
Further Outpatient Care
In/Out Patient Meds
Complications
Prognosis
Patient Education
MISCELLANEOUSSection 9 of 11
Medical/Legal Pitfalls
MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Article Last Updated: Jul 18, 2007 | |||||||||||||||||||||||||||||||||||||||||||||||||
