Reawakening of a Giant Cell Bone Tumor after 40 Years of Silence: A Rare Case Report.

Introduction: Giant cell tumor of bone (GCTB), a benign but locally aggressive tumor, may rarely undergo malignant transformation and metastasize. Although local recurrence following surgical excision with intralesional curettage is fairly common and it usually occurs within the first 3-5 years post-operatively, a low-frequency occurrence has been observed after en block resections. Case Report: A case of persistently recurrent GCTB of distal ulnar head is reported. The patient, who had undergone a Darrach procedure for excision of the tumor 40 years ago, presented with a recurrent mass at the same location. Shortly after excision of the lesion, she developed a new recurrence, which was not controlled with the monoclonal antibody denosumab, and required re-excision due to signs of ulnar nerve palsy. Conclusion: The activation of a dormant GCTB, after 40 years of silence, illustrates the need for a long-term follow-up after surgery, even when no clear evidence of tumor relapse is clinically apparent. Considering the aggressive nature of the recurrent GCTB and its potential for malignant transformation and metastasis, our case is emphasizing the importance for frequent follow-up and lifelong surveillance.