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Wheeless' Textbook of Orthopaedics

Chondroblastoma


- See: Bone Tumor Menu

- Discussion:
    - age at presentation:
          - most common primary epiphyseal tumor in children is chondroblastoma;
          - most commonly arises between ages 10 to 30;
          - not infrequently, the tumor will also arise in adults;
          - the adults counterpart of chondroblastoma is giant cell tumor;
          - in the report by Ramappa AJ, et al, 62 % of the 47 patients were 20 of age or younger (in contrast, 38% of patients will be well beyond skeletal maturity);
    - location:
          - lesions are distributed widely in the skeleton, but most were in the epiphyses or apophyses;
          - most lesions occur in the proximal part of the tibia (17%) and the proximal part of the humerus (15%); (Ramappa AJ, et al)
          - may occur in the apophysis of the greater trochanter;
          - of note, chondroblastoma is the most common tumor affecting the patella, followed by giant cell tumor;  
          - metastatic lesions are uncommon but due occur;
    - males more affected than females;
    - diff dx:
          - only three tumors may invade physis: chondroblastoma, GCT, and clear cell chondrosarcoma;
          - GCT of bone:
                  - GCT usually arises in the 3-4 decade (where as chondroblastoma arises in the second);
                  - GCT may expand to both the epiphysis and diaphysis;
          - clear cell chondrosarcoma (see chondrosarcoma)
                  - clear cell sarcoma is rare, slow growing, locally recurrent tumor easily confused with chondroblastoma but malignant;
          - epiphyseal osteomyelitis: (see: osteomyelitis);
                  - ref: Primary subacute epiphyseal osteomyelitis.

- Clinical Presentation:
    - painful - motion limiting, benign tumor arising during adolescence;
    - majority are active stage 2 lesions;

- Radiographs:
    - look for epiphseal radiolucent lesion w/ fine punctate calcifications (mineralization and a well-marginated rim of reactive bone);
    - oval osteolysis located eccentrically in the epiphysis;
    - slight bone expansion and broading of cortex;
    - tumor is usually bordered by a well defined margin of reactive bone.
    - note the amount of epiphyseal involvement and whether the tumor crosses the growth plate;
    - stage 3 chondroblastoma may extends thru growth plate into metaphysis or through articular cartilage into the joint;
    - in some cases, the tumor will erode through the subchondral bone; 

- CT Scan:
    - useful in demonstrating tissue density, extent of epiphyseal involvement, and often most imporatant location of lesion in relation to the articular and epipyseal cartilage;

- Histology of Chondroblastoma:
    - may contain areas that are histologically identical to aneurysmal bone cyst


- Treatment:
    - because condroblastoma may extend upto subcondral bone, it is difficult to perform marginal excision or complete curettage;
    - in older adolescents, currettage of growth plate may promote ephyseal closure (which avoids angular deformities);
    - stage 2
           - most chondroblastomas are active stage 2 tumors which are amenable to treatment by curettage w/ moderate risk of recurrance;
           - consists of intralesional curettage and packing with allograft or autograft bone chips or polymethylmethacrylate
           - it is important to avoid joint penetration because chondroblastoma cells will grow in joint fluid;
           - addition of methylmethacrylate to defect may be added to curettage to prevent recurrence;
    - stage 3 chondroblastoma (most common in pelvis) is not amenable to curettage due to 50% recurrance rate;
           - wide excision is the treatment of choice, if technically possible;
           - stage 3 will require en bloc excision;
           - these may metastasize to the lungs;
           - 7 patients (15 %) had a local recurrence; 3 of them had a second recurrence and one, a third recurrence;
           - patients w/ lesions around the hip (proximal femur, greater trochanter, and pelvis) are significantly more likely to develop recurrences as well as metastatic lesions (Ramappa AJ, et al)



Chondroblastoma. A review of seventy cases.

Chondroblastoma.     

Chondroblastoma of Bone.

Chondroblastoma of bone: long-term results and functional outcome after intralesional curettage. 

Treatment and Prognosis of Chondroblastoma.




Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, July 3, 2012 9:42 am