Primary Sacral Hydatid Cyst Mimicking a Neurogenic Tumor in Chronic Low Back Pain: Case Report and Review of the Literature.

Hydatid disease is caused by infection of Echinococcus granulosus. Bone hydatid cyst presentation without hepatic affectation is infrequent and occurs in 0,5-2% of cases. This rare condition makes clinicians not always aware of the disease, and as a result, misdiagnosis of spinal echinococcosis is common. We present a case of a 48-year-old female patient with primary sacral hydatidosis. Chronic low back pain radiating to the left buttock was the only symptom. The magnetic resonance imaging (MRI) suggested a neurogenic tumor versus giant cell tumor. Biopsy and pathological study revealed a hydatid cyst. Anthelmintic and surgical treatment was performed. At 12 months after surgery, the patient is free of recurrence. In patients with chronic low back pain and a MR suggestive of neurogenic tumor, spinal hydatid cyst should be considered in the differential diagnosis. It is recommended the assistance of an anesthesiologist during biopsy to avoid an anaphylactic shock.