A 69-year-old white man presented with a 5-week history of gradual onset of progressive abdominal distension. He did not report any other gastrointestinal symptoms and denied night sweats or recent travel abroad. His comorbid history included ischemic heart disease, with a myocardial infarction 11 years before this presentation. He was a former smoker, having quit 11 years ago (smoked 20 cigarettes per day for 35 years) and denied excessive alcohol intake or recreational drug use. His medications included an angiotensin-converting enzyme (ACE) inhibitor, a beta blocker, and a statin, all of which he had been taking for many years. He reported a family history of cancer, with 2 siblings deceased due to cancer of unknown origin. He had no history of previous blood transfusions, tattoos, or intravenous (IV) drug use. He was a farmer 20 years prior to presentation and had no exposure to asbestos. A clinical examination confirmed shifting dullness and the presence of ascites with no organomegaly. He had no peripheral stigmata of chronic liver disease, and the rest of the systemic examination was unremarkable.
He had a normal complete blood count, clotting, liver function tests, liver screen serum ACE level, and urine analysis, and his renal function was moderately impaired (glomerular filtration rate 51 mL/min). Serum electrophoresis was normal, with a mild but not significant elevation in the immunoglobulin G4 (IgG4) subset. Macroscopic examination of the ascitic fluid revealed a milky color with elevated triglyceride levels consistent with chylous ascites. Microscopic analysis showed a cell count of 80% lymphocytes with no evidence of a bacterial peritonitis or tuberculosis. The transudate had a normal cytological examination. Ultrasonography confirmed a large volume of ascites with a normal liver and portal vein. An abdominal and pelvic computed tomography (CT) showed a mildly enhancing soft-tissue mass lesion encasing the mesenteric renal vessels and partly encasing the upper abdominal aorta, and the pancreas was involved as well (Figure 1). There as no overt involvement of the renal areas, but the left kidney appeared slightly enlarged, suggesting a degree of ureteric involvement, although the ureters were noted to be patent. These appearances were reported to be highly suggestive of a lymphoproliferative disorder with mass lesion. A completion CT staging did not reveal any evidence of lymphadenopathy or other pathology.
Histology of a CT-guided biopsy confirmed a diagnosis of idiopathic RPF (Figure 2). Immunohistochemistry was normal and did not support Ig4 disease. The patient developed worsening renal failure during his hospital stay. A renal consult confirmed clinical intravascular fluid depletion, and IV fluids were commenced, resulting in an improvement in renal function. This confirmed a prerenal cause for the acute deterioration. Once his renal function started to improve, the rheumatologists suggested that he might benefit from corticosteroid therapy. This was mainly to prevent further progression of the inflammatory process of RPF and thereby slow or stop the advancement of obstruction and worsening of renal failure. He was given 3 pulsed doses of 500 mg IV methyl prednisolone. He was discharged and started on daily oral steroids, but the ascites rapidly reaccumulated and kidney function did not improve. Steroid therapy was discontinued. While he was on steroids, he was also started on azathioprine; this immunosuppressant was stopped due to intolerance. Since his discharge, large-volume paracentesis has been performed every 2-3 weeks for recurrent ascites. The patient currently awaits placement of an ascitic pump to allow home management.