Unusual Presentation of Herpes Zoster Infection Mimicking Soft Tissue Metastases of Breast Cancer on 18F-FDG PET/CT Imaging.

Herpes zoster infection caused by reactivation of dormant varicella zoster virus results in painful vesicular rash in corresponding dermatome. We report a case of a 56-year-old woman with breast cancer who was referred to PET/CT scan for adjuvant chemotherapy response assessment. Her scan showed multiple FDG-avid skin lesions. Blinded to the patient's clinical information, these skin lesions initially looked suspicious for soft tissue metastases. However, the patient history revealed that she had been experiencing herpes zoster infection during the scan, and these lesions with FDG uptake were eventually confirmed to be caused by herpes zoster infection by physical examination.