Liquid Absolute Alcohol Based Sclerotherapy - A Boon in Large Grade 3 Aneurysmal Bone Cyst of Proximal Humerus in a Child

INTRODUCTION: Aneurysmal bone cyst (ABC) is a benign intraosseous lesion, usually seen before the age of 20 years and is a lesion filled with blood cavities causing a blowout distension of the bone. It constitutes to about 1% of benign bone tumors. Although benign, a large lesion is liable to develop pathological fracture, so needs prompt addressal. Surgical resection or curettage in large lesions can lead to bone defects, deformities, and even functional abnormalities, especially in children. This article describes a large aggressive ABC of proximal metaphyseodiaphyseal region of proximal humerus in a 12-year-old male patient, which we managed effectively with the use of liquid absolute alcohol based sclerotherapy under fluoroscopic control. CASE REPORT: A 12-year-old boy presented to the outpatient department of our hospital presenting with complaint of swelling in the right shoulder region which was insidious in onset with gradual increase in size and deep aching pain since past 6 months. Plain radiograph revealed a large expansile osteolytic lesion with characteristic blown out “soap bubble appearance” involving the proximal humerus and abutting the growth plate. Hence, percutaneous needle biopsy of the lesion under fluoroscopic guidance was undertaken. The histology was likened to a “blood-filled sponge” composed of blood-filled anastomosing cystic cavernomatous spaces separated by wall composed of fibroblasts, myofibroblasts, and osteoclast such as giant cells, osteoid, and woven bone confirmed the diagnosis of ABC. Radiologically, it was classified as Enneking Stage 3 [1] cyst which is locally aggressive and expanding with significant cortical destruction and Capanna type 2 [2] lesion involving the entire bony segment (proximal metaphyseodiaphyseal region) with marked expansion and cortical thinning. Although resection/excision or curettage with bone grafting are commonly undertaken, concerns were for issues of subsequent bony reconstruction given the size of defect with possibility of need of an implant for stabilization, likelihood of damage to growth plate and functional compromise the shoulder. Hence, a decision to treat the patient with liquid absolute alcohol based sclerotherapy was planned. CONCLUSION: Sclerotherapy with ethanol 96% is a useful method for the treatment of large aggressive ABC, especially in children. It is a minimally invasive method, with no major complications, which lowers the risks of open surgical intervention and has a good outcome when undertaken with proper precautions.