Lupus Panniculitis Lesions Detected by FDG-PET Scan

K.S.M. van der Geest, R.V. Moerman, K.P. Koopmans, N.D. Holman, W.M.T. Janssen

Woensdag 20 april 2016

15:40 - 15:50u in Auditorium 2

Categorie├źn: Parallelsessie

Parallel sessie: Parallelsessie 2: Case reports/research

Introduction: Redness and necrosis of skin with elevated inflammatory markers usually raises suspicion of a bacterial skin infection. We describe a patient that presented with these symptoms, but had a rare autoimmune disease instead. Interestingly, a FDG-PET/CT scan provided the vital clue for the diagnosis.

Case: A 54-year old woman presented with warm, erythematous lesions on her right foot and left hand. Fever was absent, but her CRP was markedly elevated. A bacterial skin infection was suspected and antibiotic treatment was initiated. Blood cultures revealed a Staphyloccus aureus sensitive to the treatment. Although the CRP initially decreased, it rose again while new skin lesions developed. Some even became necrotic and required surgical debridement. A FDG-PET/CT scan was performed to find a source for bacterial dissemination. Unexpectedly, intense FDG uptake was observed in subcutaneous fat layers of the thighs and hands, but also at sites appearing normal on physical examination (e.g. abdomen, thorax). Histopathology of a skin biopsy, including subcutaneous fat, revealed lobular panniculitis with predominance of lymphocytes and plasma cells. Additional immunohistochemistry excluded a subcutaneous panniculitis-like T-cell lymphoma. Therefore, a diagnosis of lupus panniculitis was made. Antinuclear antibody testing was negative. Treatment with high dose corticosteroids resulted in gradual regression of her skin lesions.

Conclusion: Lupus panniculitis is a rare form of cutaneous lupus erythematosus, which may mimic bacterial skin infections, especially if a secondary skin infection is present. Although a skin biopsy is required to confirm the diagnosis, a FDG-PET/CT scan may provide the first clue towards this diagnosis.