Aneurysmal bone cysts of the sacrum

Background. Aneurysmal bone cysts, first described by Jaffe and Lichtenstein in 1942, are benign lesions that may easily be mistaken for a malignant tumor both radiographically and pathologically. These diagnostic problems are due to their rapid growth, extensive destruction of bone, wide extraosseous tumor masses, and marked cellular exuberance. The differential diagnosis of aneurysmal bone cysts including giant cell tumor, calcified solitary bone cysts, low-grade osteosarcoma, and teleangiectatic osteosarcoma becomes even more complicated when the lesion arises at sites other than the long bones and presents with extensive extraosseous, soft-tissue tumor masses. The latter cases—especially when they occur as sacral or presacral tumors—present challenges with respect to successful treatment, which should combine surgical removal of the entire lesion following oncological criteria to prevent recurrences and osteosynthesis to guarantee the biomechanical stability of the spinal-pelvic junction. Here we report on the clinical case of a female patient with an aneurysmal bone cyst of the sacrum and extensive extraosseous tumor masses. The report includes the diagnostic challenges, the surgical options of sacral and/or presacral tumors, the histopathological findings, and long-term clinical and radiographic surveillance.

Methods. The patient was treated by a combination of preoperative adjuvant selective arterial embolization, radical surgical excision through an anterior approach followed by subsequent osteosynthesis and stabilization through a posterior approach.

Results. Clinical and radiographic follow-up for 2 years was uneventful, and the patient is still free of recurrence or any complaints.

Conclusion. The current report documents the diagnostic and surgical challenge of a gigantic aneurysmal bone cyst of the sacrum and its successful management.