Retroperitoneal fibrosis

Case contributed by Dr Sherif Mohsen

Presentation

Known familial Mediterranean fever, complaining of abdominal and back pain.

Patient Data

Age: 45 years
Gender: Male
CT

A large amalgamated retroperitoneal periaortic soft tissue mass/sheet-like lesion. It is seen encasing the aorta and both common iliac arteries, associated with mild compression, yet no evidence of significant stenosis.

Nuclear medicine

FDG-PET confirms the mass lesion, showing a large metabolically active amalgamated retroperitoneal para-aortic soft tissue mass/sheet-like lesion, with maximum SUV 11.7.

Case Discussion

A known case of familial Mediterranean fever, presented with retroperitoneal periaortic soft tissue mass/sheet-like lesion, that was found to be retroperitoneal fibrosis. 

There are two types: 

  • primary (idiopathic): 2/3 of cases
    • a manifestation of systemic autoimmune or inflammatory diseases
  • secondary: 1/3 of cases
    • most commonly due to medications, neoplasms

FDG PET-CT

  • not useful as a primary diagnostic tool due to low specificity
  • allows detection of remote sites of disease
  • may help guide biopsy and assess treatment response

Top differential diagnoses

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