Bone Echinococcosis Mimicking Malignancy on FDG PET.

Area of Science:

• Medical Imaging
• Parasitology
• Oncology

Background:

• Alveolar echinococcosis is a severe parasitic disease caused by Echinococcus multilocularis.
• Bone involvement is an uncommon but significant manifestation of alveolar echinococcosis.
• Differential diagnosis of bone lesions often includes malignancy, necessitating accurate identification.

Observation:

• A 40-year-old woman presented with back pain and a thoracic vertebral lesion on MRI.
• CT scans revealed additional splenic and pulmonary masses, suggesting disseminated disease.
• 18F-FDG PET/CT demonstrated increased uptake in the vertebral lesion's periphery, characteristic of active inflammation or infection.

Findings:

• Immunological confirmation identified the cause as alveolar echinococcosis.
• The vertebral lesion exhibited compression fractures, indicating significant bone destruction.
• Coexisting splenic and pulmonary lesions were also noted, consistent with systemic parasitic spread.

Implications:

• This case underscores the necessity of including parasitic infections like alveolar echinococcosis in the differential diagnosis of bone lesions.
• Accurate diagnosis is crucial for appropriate treatment and to avoid misclassification as malignancy.
• Advanced imaging techniques like PET/CT can aid in characterizing the metabolic activity of such lesions.