Challenges in the Diagnosis and Treatment of Aneurysmal BoneCyst in Patients with Unusual Features

Aneurysmal bone cyst (ABC) is a benign but locally aggressive tumor. It has several challenging features. )e aim ofthis study is to identify challenges in the diagnosis and treatment of ABC especially in patients with unusual features.Methods.)is retrospective study involved medical record review of primary ABC patients with one or more of the following features:unusual clinical presentation with a mass or a pathological fracture especially at an unusual age, rare locations, radiologicalfindings suggesting other diagnoses especially sarcoma, and a nondiagnostic histopathology of biopsy samples.Results. 25 patients(17 males and 8 females) were included. Most patients were either younger than 10 or older than 20 years. 10 patients presentedwith a mass or a pathological fracture. Unusual locations include the scapula, the olecranon, the hamate, the calcaneus, and thefirst metatarsal bone. Extension into the epiphysis occurred in 2 patients with proximal fibula and olecranon ABCs. Two separatesynchronous cysts existed in the proximal epiphysis and middiaphysis of one humerus. Radiological imaging suggested otherprimary diagnoses in 8 patients. Core needle biopsy was diagnostic in only 2 of 7 patients. )e main treatment was intralesionalresection/curettage with bone grafting. Wide resection was performed in 4 patients. Recurrence rate was 28%. Recurrence riskfactors included the following: age less than 10 years, male gender, and proximal femur location. Late recurrence occurred in 3/7patients. One patient with asymptomatic radiological recurrence showed subsequent spontaneous resolution one year later.Conclusions. )is study presented multiple unusual features of ABC including: unusual age, rare locations, and nondiagnosticradiological and histopathological findings. )ese features can complicate the diagnosis and management. Given these features,especially with pathological fractures, a well-planned incision, the use of frozen section examination, and the application of eitherexternal fixation or plate osteosynthesis for fracture fixation can be recommended.