title: Widespread lytic lesions-A metastatic or vasculitic process?
abstract: BACKGROUND
  This case highlights the complexities in the initial diagnosis and investigations of widespread lytic lesions initially perceived to be a widespread metastatic process and the consideration of alternative diagnosis.
  
  
  METHODS
  A 57 year-old man with a background of psoriatic arthritis presented to the rheumatology department with lumbar back pain and sensory disturbance over L4/5. Magnetic resonance imaging (MRI) and bone scan identified lesions consistent with bony metastases at L5. The patient previously had a raised prostate specific antigen (PSA) of 10.8μg/L (normal<4) but prostate biopsy was benign. Multiple metastatic deposits in the liver and kidneys (confirmed necrotic tissue on biopsy) were identified through further investigations. The initial diagnosis of malignancy was challenged after a positron emission tomography (PET) scan showed lesions highly suggestive of polyarteritis nodosa (PAN) and subsequent magnetic resonance angiogram (MRA) revealed stenosis and aneurysm in the renal artery in keeping with PAN. Therefore what was initially thought to be a widespread metastatic disease process was in fact the manifestation of a systemic vasculitic disease.
  
  
  CONCLUSIONS
  PAN is a vasculitis that predominantly involves small to medium-sized vessels. The disease can affect any site in the body, but holds a predisposition for organs such as kidneys, heart and the gastrointestinal tract. Differential diagnosis of PAN should be considered in patients with widespread lytic lesions.
  
  
  CONCLUSIONS
  Due to the pathological nature of PAN and its variable clinical manifestations that add to the challenges of its diagnosis, one must hold a high clinical suspicion, even in urological conditions.
authors.affiliation: Department of Urology, Darenth Wood Road, Dartford, DA2 8DA, United Kingdom. Electronic address: fahdkhan@doctors.org.uk.
authors.forename: Fahd
authors.initials: F
authors.lastname: Khan
authors.affiliation: Department of Rheumatology, Darent Valley Hospital, Darenth Wood Road, Dartford, DA2 8DA, United Kingdom.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Srirangan
authors.affiliation: Department of Rheumatology, Darent Valley Hospital, Darenth Wood Road, Dartford, DA2 8DA, United Kingdom.
authors.forename: Yasser
authors.initials: Y
authors.lastname: El-Miedany
authors.affiliation: Department of Urology, Darenth Wood Road, Dartford, DA2 8DA, United Kingdom.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Madaan