Chondrosarcoma of the ring finger: a case report and review of the literature.

Enchondromas are the most common benign cartilaginous bone tumors arising in the medullary cavity of the small bones of the hand. In contrast, chondrosarcomas, commonly occurring in the pelvis and proximal femur and humerus, are very uncommon at this site. We report an unusual case of chondrosarcoma arising in the ring finger proximal phalanx with its radiological and histological features and reviewed the literature. The patient was an 80-year-old man whose chief complaint was swelling and pain for seven years. The findings of cortical irregular thickening by plain radiography and computed tomography and soft tissue extension by magnetic resonance imaging suggested the tumor was chondrosarcoma rather than a common enchondroma. Thorough curettage and artificial bone grafting was performed because of the age of the patient, his senile dementia and the strong desire of the patient and his family. Histological examination revealed that the tumor was composed of polygonal cells with eosinophilic cytoplasm proliferating in the chondromatous matrix with partially myxoid changes. Nuclear irregularity, binucleated cells, bone permeation and encasement were observed and the tumor was diagnosed as grade 2 chondrosarcoma. The tumor recurred five months after surgery. Amputation of the ring finger including the distal part of the 4th metacarpal was performed. At two years after surgery, the patient was free from recurrence or lung metastasis. In conclusion, details of radiological as well as pathological findings are essential for differential diagnosis between benign enchondroma and chondrosarcoma in the hand. Chondrosarcoma of the hand requires a prompt and more radical treatment than enchondroma. Wide excision is recommended to avoid local recurrence or metastasis.