title: Purulent lupus panniculitis unmasked by FDG-PET/CT scan: A case report.
abstract: BACKGROUND
  Lupus panniculitis (LP) is a unique variant of cutaneous lupus erythematosus. Clinical manifestations are typically mild and include erythema, nodules, and small ulcers. In certain cases, diagnosing LP may be challenging. Skin overlying the typical subcutaneous inflammation may appear normal, and bacterial superinfections of the skin sometimes mask the underlying LP. It has been suggested that a computed tomography (CT) scan may help to identify obscure LP lesions. Here, we report a case of a 54-year-old woman with an unusually severe form of LP, in which the full disease extent was only revealed by a fluorodeoxyglucose positron emission tomography (FDG-PET)/CT scan.
  Our patient initially presented with a bacterial infection of the skin. After initial improvement with antibiotic treatment, new erythematous lesions and sterile subcutaneous pus collections developed. An FDG-PET/CT scan revealed extensive subcutaneous inflammation at sites that had appeared normal during physical examination and on CT scan. As the subcutaneous lesions showed a remarkably linear pattern on FDG-PET/CT scan, the patient was suspected of having LP. After confirmation of this diagnosis by a deep-skin biopsy, our patient was treated with systemic glucocorticoids. Eventually, our patient succumbed to complications of LP and its treatment.
  
  
  CONCLUSIONS
  Our case demonstrates that clinical manifestations of LP are not always mild and that timely diagnosis is needed. Furthermore, we show that obscure LP lesions are more readily identified on an FDG-PET/CT scan than CT scan.
authors.affiliation: Department of Internal Medicine Department of Nuclear Medicine Department of Intensive Care Medicine, Martini Hospital, Groningen, The Netherlands.
authors.forename: Kornelis S M
authors.initials: KSM
authors.lastname: van der Geest
authors.forename: Rada V
authors.initials: RV
authors.lastname: Moerman
authors.forename: Klaas P
authors.initials: KP
authors.lastname: Koopmans
authors.forename: Nicole D
authors.initials: ND
authors.lastname: Holman
authors.forename: Wilbert M T
authors.initials: WMT
authors.lastname: Janssen
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008875:Middle Aged; D015435:Panniculitis, Lupus Erythematosus / Q000000981:diagnostic imaging*; D000072078:Positron Emission Tomography Computed Tomography