Scar sarcoidosis on 18F-FDG PET/CT

Abstract

18F-labeled fluoro-2-deoxyglucose positron emission tomography/ computed tomography (18F-FDG PET/CT) is an important imaging modality in the clinical workup of patients with chronic inflammatory disorders which present quite often with a fever of unknown origin. Sarcoidosis is a multisystem chronic inflammatory disorder with a wide clinical spectrum that can involve different organs. The diagnosis of sarcoidosis is usually based on the observation of noncaseating granulomas in biopsy specimens and exclusion of other granulomatous diseases. Skin involvement can occur in 20-25% of sarcoidosis cases. However, scar involvement in sarcoidosis is a rare condition. Herein, we present a case of multisystem sarcoidosis in a 45-year-old woman, who was previously treated with steroids and was in remission for 8 months. The patient presented with multiple skin nodules on the chest and back, a history of intermittent fever, headache, and mild itching at the abdominal scar site for 3 months. Blood investigations revealed elevated serum angiotensin-converting enzyme levels. The 18F-FDG PET/CT revealed a metabolically active involvement of the cutaneous tissue (posthysterectomy scar), apart from other sites of involvement. Biopsy of the scar site revealed multiple epithelioid cell granulomas with giant cells surrounding the collagenous fibers of the scar tissue