|LETTER TO EDITOR
|Year : 2011 | Volume
| Issue : 2 | Page : 276-277
Atypical solitary enchondroma of radius
PG Vijay, A Asharaf, U Jayaprakash
Department of Orthopaedics, MES Medical College, Palachode P.O., Perinthalmanna, Kerala, India
|Date of Web Publication||11-Jul-2011|
P G Vijay
Department of Orthopaedics, MES Medical College, Palachode P.O., Perinthalmanna, Kerala
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Vijay P G, Asharaf A, Jayaprakash U. Atypical solitary enchondroma of radius. Indian J Cancer 2011;48:276-7
'Approximately 35% of all enchondromas arise in the hand',  followed by femur, humerus, and tibia. 'Solitary enchondroma of radius is rare'.  Even after extensive literature search, reference for exact incidence of solitary enchondroma in radius is not found, although '1% incidence is quoted for radius and ulna'.  Only one out of 136 cases in Huvos series,  occurred in the radius (metaphyseal region). 'Typical enchondroma is an incidental finding, while atypical is associated with pain'.  We are presenting a rare case of atypical (associated with pain) solitary enchondroma of radius.
An 18 - year-old female presented with pain in the left forearm for about 4 weeks. Pain started after lifting weights and aggravated by physical work. There was no history of night pain. There was a similar episode of pain 1-year back, which was treated by a nature bonesetter by immobilizing the limb for about 4 weeks. After that, the patient was relatively symptom-free.
X-ray [Figure 1] showed multiple radioluscent lesions in the middle and distal radial diaphysis extending into metaphysis. Faintly opaque radioluscent area and mild-endosteal erosions seen in two to three sites; bony expansion was noted at two sites. There was no obvious pathological fracture, calcification, or soft tissue involvement.
Routine blood examination, calcium, phosphorus, alkaline phosphatase, PTH assay, skeletal survey were all normal. The preoperative differential diagnoses considered are fibrous dysplasia, simple bone cyst, and enchondroma.
Intraoperatively 9 cm long and 2 cm wide lesion was seen. Most of the dorsal cortices were weak and a pale blue cartilaginous tissue was curetted out. Curettage and bone grafting of the residual defect with ipsilateral fibula slices were done through a dorsal approach [Figure 2]a and b. Postoperatively, the patient was immobilized with cast for 8 weeks. Histopathology showed cartilaginous hypercellular areas without pleomorphism, binucleate cells, and marrow infiltration [Figure 3].
|Figure 2: (a) Four weeks postoperative AP. (b) Four weeks postoperative lateral|
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At 2-year follow up, patient was found to be completely symptom-free, have full ROM(range of motion) and back to normal activities [Figure 4]. X-ray showed almost full graft incorporation 'Typical enchondromas showed benign biologic behavior, where atypical is a more ominous condition, may be associated with a malignant change (low-grade chondrosrcoma)'.  Chondrosrcomas, if missed usually recur in 2 years, but needs follow up for 10 years.
Pain can be caused by weakening of bone, which may undergo stress fracture after strenuous activities. We could not find out any obvious fracture preoperatively or intraoperatively. Any patient that experiences sudden pain after physical stress is more likely to have an enchondroma rather than a chondrosarcoma.  In chondrosarcoma, pain is usually insidious and progressive. 'Soft tissue mass and night pain is present in >20% cases'. 
Radiological features such as cortical destruction, periosteal reaction, and soft tissue mass strongly suggest the diagnosis of chondrosarcoma. The differentiation between enchondroma and grade 1 chondrosarcoma can be quite difficult histologically. The cytological features often overlap.
The differentiation of solitary enchondroma and chondrosarcoma is based on clinical, radiological, and histopathological findings. Our patient does not have any features of chondrosarcoma at 2 years, although she needs more follow up.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]