Large Peri-Renal Fluid Collection Involving Gerotaʼs Fascia After Acute Pancreatitis

Abstract

A 19-year-old male presented with third episode of recurrent idiopathic acute pancreatitis. Upon presentation, a CT scan of the abdomen was notable for acute fluid collection formation at the tail of the pancreas (figure 1). The patient was medically managed with aggressive hydration and pain control and was discharged in good health. He presented again after 4 weeks with left flank pain, nausea and vomiting. A repeat CT scan of the abdomen demonstrated a peri-renal fluid collection beneath the Gerota's fascia of the left kidney. The patient was afebrile with stable vital signs. Urinanalysis was unremarkable. Complete blood counts and basic metabolic profile were normal. Urology consultation was obtained for concern for renal compromise from compression effects given the size of the fluid collection, and possible hemorrhage into the peri-renal space from an undetected renal angiolipoma. The patient denied any history of trauma. Urology deemed the fluid not consistent with the kidney origin given no trauma history and no visible tumor on the imaging. MRI of the abdomen performed after four days revealed increasing size of the encapsulated renal fluid collection measuring 17 cm x 12 cm x 12 cm (figure 3). A CT guided drainage of the fluid collection was performed and one liter of dark green non-turbid fluid was drained (figure 4). Investigation of the fluid demonstrated white blood cell count of 4070, amylase of >13000, and lipase of >30000 consistent with pancreatic fluid. Acute and chronic pancreatitis are known to have complications which include the development of a pseudocyst. Pseudocysts occur weeks after the onset of pancreatitis and account for an incidence rate of nearly 5-15%.However, Pseudocysts which have involved the Gerota's fascia of the magnitude seen in our case have very rarely been reported in English literature.In majority of the cases, ultrasonographic or CT guided aspirations were the main stay of therapy which demonstrated definitive resolution. It is postulated that the autolytic nature of pancreatic enzymes allows the fluids to dissect through fascial planes leading to distant pseudocyst formation. Pancreatic pseudocysts with atypical locations such as the peri-renal space are radiologically challenging to diagnose as they often mimic an underlying malignant process or traumatic history. These atypical locations pose and therapeutic challenges which may encompass surgical, percutaneous, or transgastric intervention.1314_A.tif Figure 1: A computed tomography (CT) coronal view image of the abdomen was notable for acute fluid collection “phlegmon” formation at the tail of the pancreas1314_B.tif Figure 2: A computed tomography (CT) abdomen axial image revealing development of peri-renal subcapsular fluid accumulation1314_C.tif Figure 3: Magnetic resonance cholangiopancreatography image demonstrating peri-renal fluid collection involving the Gerota's fascia of the left kidney and measured 17 cm x 12 cm x 12 cm.