Cat-Scratch Disease: A Pitfall for Lymphoma Evaluation by FDG-PET/CT

Area of Science:

• Oncology
• Nuclear Medicine
• Infectious Disease

Background:

• Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography (FDG-PET/CT) is crucial for staging and monitoring Hodgkin lymphoma.
• Accurate interpretation is vital due to the significant therapeutic implications of staging and response assessment.

Observation:

• A patient with stage III bulky Hodgkin lymphoma achieved complete metabolic response on interim FDG-PET/CT.
• Following additional chemotherapy, the patient presented with fever and lymphadenopathy.
• Repeat FDG-PET/CT demonstrated increased uptake in inguinal and iliac lymph nodes.

Findings:

• Pathological and serological analyses confirmed a diagnosis of cat-scratch disease.
• The findings indicate that cat-scratch disease can present as FDG-avid lymphadenopathy, mimicking lymphoma progression or relapse.

Implications:

• This case underscores the importance of considering infectious etiologies in FDG-PET/CT findings, especially in lymphoma patients.
• Clinicians should integrate clinical, pathological, and microbiological data to avoid misdiagnosis and inappropriate treatment escalation.
• Recognizing FDG-PET/CT pitfalls is essential for optimizing patient management in Hodgkin lymphoma.