A 31-year-old immunocompetent woman presented with a large sacral mass on the left side, concerning for a neoplastic process. A biopsy specimen demonstrated fungal osteomyelitis. Intraoperatively, the left S1 sacral nerve root was found to be necrotic, consistent with the symptoms of numbness and weakness. The infection was resolved with aggressive surgical debridement and long-term therapy with antifungal medication.
Fungal osteomyelitis of the sacrum is rare, especially in an immunocompetent patient, and untreated infections can cause nerve root necrosis. We recommend aggressive surgical and antifungal management to avoid neurologic compromise.