Solid variant of aneurysmal bone cyst in the tibia treated with simple curettage without bone graft: a case report

The solid variant of aneurysmal bone cyst (solid ABC) is rarely encountered in long bones and appropriate treatment for this disease remains unclear. We experienced a 13-year-old boy suffering from pain in his left knee caused by solid ABC. Simple curettage of the bone lesion without any adjuvant therapy and a bone graft gave immediate pain relief. Histological examination of the surgical specimen showed typical features of solid ABC, and cycloxygenase-2 (COX-2) expression was confirmed in giant cells with a background of spindle cells by immunohistochemistry. Magnetic resonance imaging showed that soft tissue edema surrounding the lesion was improved two months after surgery and there was no indication of recurrence two years after surgery. If COX-2 secreted from the tumor induces soft tissue edema, simple curettage of the bone lesion seems to be a reasonable treatment for solid ABC and is able to minimize invasive treatment of the patients.