Blastomycosis of long bones.

The presentation of blastomycosis clinically and radiographically is nonspecific and often mistaken for a neoplasm. Delay in diagnosis is common. Patients with osseous blastomycosis present with pain and swelling. Radiographs usually show an eccentric lucency in the distal ends of long bones. These patients frequently are referred for a neoplastic workup and a diagnosis is made only after biopsy. We review the cases of five patients diagnosed with a bone tumor who had blastomycosis osteomyelitis. The time to diagnosis from original symptoms was 4.7 months (range, 3-8 months). The average age of the patients was 45.6 years (range, 20-59 years). A Musculoskeletal Tumor Society functional assessment was done. Early radiographs of the current patients ranged from normal to showing faint osteopenia in the involved location. As the disease progressed, the area of lucency appeared with either diffuse or well-marginated borders. Treatment included surgical debridement with antifungals. The mean functional score was 93.3%. All patients are disease-free. Blastomycosis, similar to tuberculosis, often is mistaken for a neoplasm. Blastomycosis osteomyelitis can be treated with excellent results. The key is diagnosis and including endemic fungal infections in the differential diagnosis of bone tumors. In addition, every potential neoplasm should include cultures of specimens obtained at biopsy.