Scar arcoidosis on ¹⁸F-FDG PET/CT

Area of Science:

• Immunology
• Radiology
• Dermatology

Background:

• Sarcoidosis is a multisystem chronic inflammatory disorder.
• Skin involvement is seen in 20-25% of cases, but scar involvement is rare.
• Diagnosis typically relies on biopsy showing noncaseating granulomas and excluding other conditions.

Observation:

• A 45-year-old woman in remission for sarcoidosis presented with skin nodules, fever, and headache.
• Itching at an abdominal scar site was noted.
• Elevated serum angiotensin-converting enzyme levels were detected.

Findings:

• 18F-FDG PET/CT imaging showed metabolically active involvement of the posthysterectomy scar.
• Biopsy of the scar revealed noncaseating granulomas with epithelioid and giant cells.
• Multisystem sarcoidosis was confirmed, with scar involvement as a rare finding.

Implications:

• This case underscores the utility of 18F-FDG PET/CT in diagnosing rare sarcoidosis presentations.
• It expands the understanding of sarcoidosis's potential to affect scar tissue.
• Highlights the importance of considering scar sites in the workup of recurrent sarcoidosis.