Osteomyelitis and septic arthritis after Mycobacterium Bovis BCG Therapy for Urinary Bladder Cancer

Abstract Mycobacterium bovis (M. bovis) Bacillus Calmette-Guerin (BCG) – an attenuated strain of M. bovis – is closely related to Mycobacterium tuberculosis and may be used as a vaccine against tuberculosis as well as a treatment for urinary bladder cancer. Complications of M. bovis BCG administration, while rare, can occur. While a few cases of vertebral osteomyelitis secondary to BCG therapy exist in the literature, and while there are case reports of osteomyelitis and septic arthritis from BCG vaccination (Chen et al., 2017; Huang et al., 2019; Lin et al., 2015 [ [1] , [2] , [3] ]), there are no reported cases of osteomyelitis and septic arthritis involving the foot from BCG therapy for urinary bladder cancer. We present an unusual presentation of osteomyelitis and septic arthritis of the tarsometatarsal joints after M. bovis BCG therapy for urinary bladder cancer. We will describe MRI and ultrasound findings in our case of M. bovis BCG osteomyelitis and septic arthritis.