EC Orthopaedics

Aneurysmal bone cyst (ABC) is a benign but locally aggressive primary bone tumor, predominant in children and young adults. It can affect any bone in the body with possible soft tissue involvement, but the metaphysis of the long bones is the preferred location. The systemic approach to make the diagnosis of this lesion consists of simple X-rays, however cross-sectional imaging, especially MRI, allows more details and the exclusion of differential diagnoses, mainly telangiectatic osteosarcoma. We report the case of a 40-year-old man who presented with a painful hip whose radiograph showed a well-defined lytic lesion of the head and neck of the right femur revealed to be an ABC on MRI. We approach through this case the main diagnostic criteria of an ABC and the mimicking situations including the "ABC-like.

Keywords: Aneurysmal Bone Cyst; Extensive Pancephalic; Lesion; MRI; Differential Diagnosis

1. Zehetgruber H., et al. “Prevalence of aneurysmal and solitary bone cysts in young patients”. Clinical Orthopaedics and Related Research 439 (2005): 136‑1
2. Cottalorda J., et al. “Epidemiology of aneurysmal bone cyst in children: a multicenter study and literature review”. Journal of Pediatric Orthopaedics B6 (2004): 389‑394.
3. Bonakdarpour A., et al. “Primary and Secondary Aneurysmal Bone Cyst: A Radiological Study of 75 Cases”. Radiology 1 (1978): 75‑83.
4. Sasaki H., et al. “Diagnosing and discriminating between primary and secondary aneurysmal bone cysts”. Oncology Letters4 (2017): 2290‑2296.
5. Organisation mondiale de la santé, Centre international de recherche sur le cancer, éditeurs. Soft tissue and bone tumours. 5^th Geneva: OMS. (World health organization classification of tumours) (2020).
6. Lichtenstein L. “Aneurysmal bone cyst. A pathological entity commonly mistaken for giant-cell tumor and occasionally for hemangioma and osteogenic sarcoma”. Cancer2 (1950): 279‑289.
7. Agaram NP., et al. “USP6 gene rearrangements occur preferentially in giant cell reparative granulomas of the hands and feet but not in gnathic location”. Human Pathology6 (2014): 1147‑1152.
8. Oliveira AM., et al. “USP6 (Tre2) Fusion Oncogenes in Aneurysmal Bone Cyst”. Cancer Research6 (2004): 1920‑1923.
9. Capanna R., et al. “Aneurysmal cysts of long bones”. Italian Journal of Orthopaedics and Traumatology4 (1985): 409‑417.
10. Mascard E., et al. “Bone cysts: Unicameral and aneurysmal bone cyst”. Orthopaedics and Traumatology: Surgery and Research 1 (2015): S119‑S127.
11. Rapp TB., et al. “Aneurysmal Bone Cyst”. Journal of the American Academy of Orthopaedic Surgeons4 (2012): 233‑241.
12. Zishan US., et al. “The differentiation between aneurysmal bone cyst and telangiectatic osteosarcoma: a clinical, radiographic and MRI study”. Skeletal Radiology9 (2020): 1375‑1386.
13. Mahnken A., et al. “Aneurysmal bone cyst: value of MR imaging and conventional radiography”. European Radiology 5 (2003): 1118‑1124.
14. Rajeswaran G., et al. “The role of needle biopsy for focal bone lesions with complete fluid-fluid levels on magnetic resonance imaging”. Skeletal Radiology 6 (2013): 765‑769.
15. Sasaki H., et al. “Diagnosing and discriminating between primary and secondary aneurysmal bone cysts”. Oncology Letters4 (2017): 2290‑2296.
16. Yin J qiang., et al. “Telangiectatic osteosarcoma: Outcome analyses and a diagnostic model for differentiation from aneurysmal bone cyst”. Journal of Bone Oncology 11 (2018): 10‑1
17. Rosenblatt J and Koder A. “Understanding Unicameral and Aneurysmal Bone Cysts”. Pediatrics in Review 2 (2019): 51‑59.
18. Masthoff M., et al. “Combined Transarterial Embolization and Percutaneous Sclerotherapy as Treatment for Refractory and Nonresectable Aneurysmal Bone Cysts”. Journal of Vascular and Interventional Radiology 10 (2021): 1425-1434.e2.
19. Malghem J., et al. “Spontaneous healing of aneurysmal bone cysts. A report of three cases”. The Journal of Bone and Joint Surgery British Volume4 (1989): 645‑650.