Primary Aneurysmal Bone Cyst and Its Recent Treatment Options: A Comparative Review of 74 Cases

SIMPLE SUMMARY: This single-center study is a retrospective review of 74 patients with primary aneurysmal bone cysts (ABCs). It aims to compare the three most common treatment options—intralesional curettage, the percutaneous instillation of polidocanol and en bloc resection. It is the first study comparing these three treatment options using MR scans for the evaluation of the treatment success of instillation therapy and demonstrates the superiority of MRI scans compared to conventional radiographs for cyst volume measurement. The study confirms the efficacy of polidocanol instillations for primary ABCs and justifies it as standard treatment option. However, in this study several instillations were found to be necessary to achieve complete healing or at least stable disease. In a relevant number of cases a conversion to a surgical treatment was necessary. Thus, in this study we relativize the so-far highly positive treatment results reported for instillations in the literature, and rate them skeptically. ABSTRACT: (1) Background: An aneurysmal bone cyst (ABC) is a benign, locally aggressive tumor. Different treatment modalities are described in the literature i.e., en bloc resection, intralesional curettage and percutaneous sclerotherapy. (2) Methods: This single-center study is a review of 74 patients with primary ABCs who underwent a surgical treatment or polidocanol instillation. Cyst volume measurements using MRI and conventional radiographs are compared. (3) Results: The mean pre-interventional MRI-based cyst volume was 44.07 cm(3) and the mean radiographic volume was 27.27 cm(3). The recurrence rate after intralesional curettage with the need for further treatment was 38.2% (13/34). The instillation of polidocanol showed a significant reduction of the initial cyst volume (p < 0.001) but a persistent disease occurred in 29/32 cases (90.6%). In 10 of these 29 cases (34.5%) further treatment was necessary. After en bloc resection (eight cases) a local recurrence occurred in two cases (25%), in one case with the need for further treatment. (4) Conclusions: MRI scans are superior to biplanar radiographs in the examination of ABCs. Sequential percutaneous instillations of polidocanol are equally effective in the therapy of primary ABCs compared to intralesional curettage. However, several instillations have to be expected. In a considerable number of cases, a conversion to intralesional curettage or en bloc resection may be necessary.