Background <p>Giant Cell Tumour (GCT) of bone is a benign but locally aggressive tumour, rarely involving the distal ulna. Due to its anatomical uniqueness and limited literature, management remains controversial. While curettage has a high recurrence rate, wide resection can compromise function and often necessitates complex reconstruction.</p> Case presentation <p>A 48-year-old female presented with a six-month history of pain and swelling over the distal ulna. Imaging and histopathology confirmed a Campanacci stage II GCT. She underwent en-bloc resection of the distal ulna with a 2&#xa0;cm margin, followed by soft tissue stabilisation using Extensor Carpi Ulnaris (ECU) and Flexor Carpi Ulnaris (FCU) tendon reattachment. Postoperative recovery was uneventful, with a DASH score improving from 49.2 to 4 over six months. At one year, the patient demonstrated full wrist function with no signs of recurrence or instability.</p> Discussion <p>This case supports en-bloc resection with tendon stabilisation as a safe and functionally effective option for distal ulna GCT. Given the anatomical challenges and absence of standard reconstructive protocols for this site, this simplified approach minimised morbidity while preserving wrist biomechanics.</p> Conclusion <p>En-bloc resection with soft tissue stabilisation resulted in excellent early functional outcomes in this case of Campanacci stage II GCT of the distal ulna. While limited by single-case design and short-term follow-up, this approach may be considered in selected cases where complex reconstruction is deemed unnecessary. Longer-term prospective studies are needed to validate these findings and establish definitive treatment protocols for this rare tumour.</p>