Update on aneurysmal bone cyst: pathophysiology, histology, imaging and treatment

Abstract

Aneurysmal bone cyst (ABC) is a benign but locally aggressive lesion that predominantly affects children and young adults. ABC, which accounts for approximately 70% of the cases, is now recognized to be a true neoplasm, whereas ABC-like changes associated to other bone neoplasms (also referred in the literature as secondary ABC) accounts for the remaining 30%. The solid variant of ABC is also considered a true neoplasm but is rare. ABC can involve any bone in the body, and although it has a metaphyseal preference, it can involve any part of a bone and soft tissues. As with any bone tumor, the initial evaluation of ABCs should be done with radiographs followed by magnetic resonance imaging or less frequently computed tomography for further characterization. The imaging appearance of ABC is variable; however, a lytic and expansile lesion with fluid-fluid levels is the most common presentation. The main differential diagnosis of an ABC in the pediatric population is unicameral bone cyst (UBC) and telangiectatic osteosarcoma, therefore a biopsy is recommended before treatment. The therapeutic options of ABC range from curettage with or without adjuncts such as phenol, liquid nitrogen, argon laser and bone grafting or bone substitutes to more recently employed alternatives such as image-guided sclerotherapy with various sclerosing agents and monoclonal antibodies (e.g., Denosumab).

Skull base chondroblastoma with aneurysmal bone cyst–like changes treated with percutaneous radiofrequency ablation and doxycycline sclerotherapy: illustrative case

“…ABCs are benign, locally aggressive bone tumors that commonly develop in the metaphyses of long bones. 4 Approximately 30% of these cases represent ABC-like changes associated with other primary bone tumors, such as a CB. 4 , 5 Percutaneous doxycycline sclerotherapy has been used to treat ABCs with proven safety and efficacy.…”

“… 4 Approximately 30% of these cases represent ABC-like changes associated with other primary bone tumors, such as a CB. 4 , 5 Percutaneous doxycycline sclerotherapy has been used to treat ABCs with proven safety and efficacy. 11 , 12 Shiels et al 11 successfully treated 21 ABCs with a low recurrence rate of 5%.…”

“… 3 Aneurysmal bone cysts (ABCs) are benign, expansile, osteolytic lesions that constitute 1% of bone tumors. 4 , 5 Tumors with ABC-like changes, previously called “secondary ABCs,” represent 30% of ABC cases and present with the radiological appearance of an ABC associated with a separate bone tumor. 4 , 5 CBs are one of the more common tumors associated with ABC-like changes (22%).…”

“…4,5 Tumors with ABC-like changes, previously called "secondary ABCs," represent 30% of ABC cases and present with the radiological appearance of an ABC associated with a separate bone tumor. 4,5 CBs are one of the more common tumors associated with ABC-like changes (22%). 5 Traditional treatment for CBs or ABCs is open surgical removal with or without adjuvants, bone grafting, and fixation, but it has a recurrence rate as high as 32%, especially in surgically complex locations.…”

Soft tissue aneurysmal bone cyst in thigh muscles: A case report

“… 2 The most expected locations for ABCs are the metaphysis of long bones and vertebral bodies. 3 In MRI, they present as lytic lesions with sharp borders, bone expansion, and fluid–fluid level. 4 …”