Abstract

Introduction: Several benign and malignant bone tumors have aneurysmal content. Primary ABC (aneurysmal bone cyst), secondary aneurysmal bone cyst, and telangiectatic osteosarcoma are the most common. Confirming diagnosis of biopsy of cystic tumors with aneurysmal content was a dilemma because it was difficult to obtain adequate tissue for pathology and presents risks. Surgeons may choose to remove a lesion without the need for preoperative biopsy. However, the criteria for this are not well defined. The purpose of this study was to develop an algorithm for clinical decision-making using a score based on the lesion’s main characteristics.

Methods: We conducted a retrospective analysis of bone tumors diagnosed as primary ABC (10 cases), secondary ABC (7 cases), and telangiectatic osteosarcoma (2 cases) between 2008 and 2019. A protocol was devised containing age, diagnosis, and imaging. Through literature review and data collected from the devised protocol criteria, including age, location, type of bone destruction, amount of fluid-fluid level, biological behavior, presence of solid component, and pathological fracture, a score between 0 and 8 was generated.

Results: The threshold established to discriminate the need for biopsy was 3.5 (sensitivity 88.9%, specificity 90%, positive predictive value 88.9%, and negative predictive value 90%). Benign tumors, such as primary ABC (10 cases), scored 2 – 4; secondary ABC (7 cases) scored 3-7; and telangiectatic osteosarcoma (2 cases) scored 6.

Conclusion: According to our findings it is possible to remove some tumors with aneurysmal content without prior biopsy using the decision algorithm, whose criteria were based on the features that needed the most attention. The algorithm scores from 0-8, separates lesions into lower and higher aggressiveness, indicates cases that require biopsy and can be used only by evaluating the MRI scan. Tumors scoring ≤ 3 can be treated without prior biopsy with curettage and adjuvant therapy. Tumors with other scores should be biopsied.