Solid Variant Aneurysmal Bone Cyst of the Trapezoid Bone: A Case Report.

An aneurysmal bone cyst (ABC) is classified as a benign osteoclastic giant cell-rich tumour. We report a case of a 48-year-old male patient with a solid variant ABC involving the trapezoid bone. We chose to fill the defect with bone cement after curettage. At the 12-month follow-up, the patient remained recurrence-free with satisfactory hand function. Carpal bone tumours are rare and typically benign, with malignant and metastatic lesions being extremely uncommon. We were unable to find any other reports of a solid variant ABC in the trapezoid bone. This case highlights the importance of histopathological and genetic analyses to achieve a definitive diagnosis of solid variant ABCs in atypical presentations. Level of Evidence: Level V (Therapeutic).