Pyomyositis mimicking osteomyelitis detected by SPET/CT

Area of Science:

• Nuclear Medicine
• Radiology
• Infectious Diseases

Background:

• Pyomyositis is a rare bacterial muscle infection often misdiagnosed due to nonspecific symptoms, particularly in diabetic patients.
• Delayed diagnosis of pyomyositis can lead to severe complications or fatality.
• Prompt diagnosis and treatment are crucial for managing pyomyositis.

Observation:

• A diabetic patient initially suspected of osteomyelitis showed false-positive bone scan results.
• Single photon emission computed tomography/computed tomography (SPET/CT) revealed muscle uptake and lesions, not bone involvement.
• Magnetic resonance imaging (MRI) confirmed intramuscular abscesses, aiding in the pyomyositis diagnosis.

Findings:

• SPET/CT effectively differentiated pyomyositis from osteomyelitis by localizing abnormal uptake to the calf muscles.
• MRI provided detailed visualization of inter- and intra-muscular collections consistent with abscesses.
• Combined imaging modalities were essential for establishing the correct diagnosis of pyomyositis.

Implications:

• SPET/CT is a valuable tool for the early and accurate detection of pyomyositis.
• Integrating SPET/CT into diagnostic pathways can improve management of challenging pyomyositis cases.
• This case highlights the importance of advanced imaging in diagnosing atypical presentations of infection in diabetic patients.