Nonsurgical treatment of lumbosacral blastomycosis involving L2-S1

Objective. To discuss the diagnosis and treatment of Blastomyces dermatitidis in the spine. Summary of Background Data. Blastomycosis, like other fungal organisms, has a nonspecific appearance on radiographs, and is often mistaken for TB or a neoplasm. Nonsurgical treatment of this infection is possible, however, as seen in this case. The difficulty in diagnosing fungal infections often leads to a delay in treatment. Methods. We report on a 37-year-old Arabian woman who presented initially with progressive low back and anterior thigh pain without precipitating trauma. She was found to have 2 draining fistulas. Computed tomography-guided percutaneous drainage of the paravertebral phlegmon yielded purulent material that was pan cultured. The KOH preparation was consistent with a fungal pathogen, which was later identified as Blastomyces dermatitidis by polymerase chain reaction. Results. Radiologic studies of the lumbar spine and sacrum performed revealed extensive involvements with osseous destruction of L2-S1. The destruction was most severe at L3 with mild boney retropulsion at that level. Throughout the patient's treatment course, she complained of mild-to-moderate lower back pain and had no neurologic symptoms. Therefore, surgery was deferred. Conclusion. There are no pathognomonic findings of blastomycosis on magnetic resonance imaging. Fungal osteomyelitis is rarely identified in this country, and blastomycosis is even less often diagnosed. This case illustrates that fungal osteomyelitis should be considered in the radiographic differential diagnosis until a definitive diagnosis is made through biopsy.