An aggressive aneurysmal bone cyst of the proximal humerus and related complications in a pediatric patient

Abstract

Clinical behavior of aneurysmal bone cyst (ABC) in younger patients can be more aggressive than that in older children and adults. Angular deformity and shortening can occur due to growth plate destruction or tumor resection. A 11-year-old boy who had been operated twice in another center for an ABC located in the left proximal humerus presented to the author's institution with complaints of pain, deformity and shortening of the left arm. Plain radiographs revealed left proximal humerus nonunion with a large defect. Reconstruction with nonvascularized fibular autograft was applied and left upper extremity was immobilized in a velpou bandage. At the third-month follow-up, graft incorporation was observed in the distal part; however, proximal part did not show adequate healing on radiographs. Additional immobilization in a sling for 3 months was advised to the patient and his family. However, they were lost to follow-up and readmitted to the author's institution at the 12th month postoperatively. Radiographs showed failure of the fibular graft fixation and nonunion of the humerus. Autogenic bone grafts, either vascularized or nonvascularized are the best treatment method for the large defects after tumor curettage or resection. Nonvascularized grafts are technically much easier to use than vascularized grafts and provide excellent structural bone support at the recipient side. However, they may take several months to be fully incorporated. In addition, good therapeutic outcomes require patience and collaboration with the patient and parents. Most importantly, the patient should be monitored closely.

Fig. 1

Clinical photographs of the patient show shortening of the left arm (a), restriction of the left shoulder motion (b) and old scar tissues on the left arm (c)

Fig. 2

Anteroposterior radiograph (a) and coronal MRI scans (b, c) of the left shoulder and arm show the blowout appearance of the left proximal humerus. A multiloculated cystic and expansile lesion involving the proximal humeral metaphysis adjacent to the growth plate can be identified. Axial MRI scan (d) indicates a fluid–fluid levels in the cystic lesion

Fig. 3

Plain radiograph after initial operation (a) indicates en bloc resection of ABC and reconstruction with cortical strut allograft. One year after the index operation, anteroposterior radiograph (b) shows failure of fixation with fracture of strut allograft and nonunion of the humerus

Fig. 4

Anteroposterior radiograph (a) shows proximal humerus nonunion with a large defect containing allografts. After the operation at author’s institution, plain radiograph (b) shows reconstructed defective area with fibular autograft that was secured by one K wire. Fibular autograft was obtained from the contralateral extremity (c). At the third-month follow-up, plain radiograph shows graft incorporation in the distal part of the fibular graft with inadequate healing of the proximal part (d)

Fig. 5

At the end of 12th month follow-up, anteroposterior radiograph (a) shows failure of the fibular graft fixation and nonunion of the humerus. Plain radiograph of the right leg (b) shows new bone formation in the donor side without any angular deformity