Ureter and Nerve Root Compression Secondary to Expansile Fibrous Dysplasia of the Transverse Process

Considering their proximity to abdominal viscera, transverse process lesions may pose a diagnostic challenge. We present a case of fibrous dysplasia of the transverse process, causing urinary retention, frequent urinary tract infections, and thigh numbness. This is the first reported case of a transverse process fibrous dysplasia lesion, causing simultaneous urinary retention and neurologic symptoms. Clinicians may consider lesions of the lumbar transverse processes in patients presenting to orthopedic surgeons with urinary symptoms, especially when combined with neurologic symptoms. In these lesions, fibrous dysplasia should be within the differential diagnosis. We discuss the diagnosis and present a brief review of fibrous dysplasia.