Mohammed CS Saheed MS DNB; Department of Urology, Amrita Institute of Medical Sciences, Elamakkara PO, Kochi 682026, Kerala, India. Email: email@example.com
Abstract Idiopathic retroperitoneal fibrosis (RPF) is one of the causes of obstructive uropathy. This disease, ever since its original description in 1948, has undergone much trial and error in its management. We present a case of a rare type of idiopathic RPF causing obstructive uropathy, which is perirenal and different from the classical RPF seen around the great vessels. To our knowledge, such a type of RPF has not been described. We treated the patient by a combined surgical approach in the form of ureterolysis and omentoplasty, followed by medical management with steroids and tamoxifen. The combined regimen yielded excellent results, and the patient is doing well at 9 months of follow up. The rarity of the presentation, with predominant bilateral perirenal fibrosis, and response of perirenal RPF to steroids and tamoxifen, is highlighted in this case presentation.
Obstructive uropathy due to idiopathic retroperitoneal fibrosis is a common presentation in urologic practice. The disease has been recognized since 1948 and various treatment modalities have been described over the years.1,2 In this report, we have highlighted a very rare presentation and a novel management strategy in a case of primary retroperitoneal fibrosis.
A 47-year-old, hypertensive male was referred to our center with history of acute renal failure and symptoms of recurrent dull backache, loss of weight and loss of appetite for 3 months. He had undergone two sessions of hemodialysis after a failed DJ stenting for obstructive uropathy. There was no past history of trauma, loin pain, tuberculosis, irradiation or medication for chronic illness. Physical examination was unremarkable except for pallor and bilateral pedal edema. Contrast-enhanced computed tomography (CT) scan revealed a bilateral perirenal nonenhancing mass encasing the kidneys circumferentially and extending across the midline great vessels (Fig. 1a,b). The right kidney was hydronephrotic with minimal handling of contrast. His hematologic and biochemical profile revealed normochromic normocytic anemia, raised erythrocyte sedimentation rate and a serum creatinine of 2.5 mg/dL. Dimercapto succinic acid scan revealed a poorly functioning right kidney with 5% uptake and a suboptimally functioning left kidney. A CT guided biopsy of the mass done elsewhere was reported suspicious of Schwannoma. A CT guided biopsy repeated at our center, and a review of the previous slides from elsewhere revealed histology suggestive of an inflammatory process with fibrosis and without any feature suggestive of malignancy. The antegrade pyelogram revealed left upper ureteral narrowing at the level of L4 transverse process causing obstruction, and the ureter was DJ stented. Considering the possibility of tuberculosis, which is endemic in this part of the world, the patient was empirically started on antituberculous chemotherapy. He was discharged and advised to follow up after 2 months. His renal functions stabilized, but systemic symptoms persisted. We decided to explore and proceed according to frozen section biopsy. On exploratory laparotomy, the classical glistening white, unyielding retroperitoneal fibrosis was encountered. The plaque predominantly encased both kidneys. It extended over the renal pelvis and upper ureters on both sides up to the level of aortic bifurcation and encased the great vessels in the midline. The inferior extent of the lesion was typical of classical retroperitoneal fibrosis (RPF). Frozen sections revealed only fibrous tissue with chronic inflammation. Bilateral ureterolysis of the ureters was done, as there was a clear plane definable periadventitally between the ureters and fibrotic mass. After placement of bilateral DJ stents through ureterotomies, pedicled omental wrapping of the ureters was done. The histopathology revealed dense fibrocollagenous tissue with fibroblasts, adipose tissue, vascular proliferation with inflammatory cells, hemosiderin-laden macrophages and lymphoid aggregates, which was consistent with inflammatory phase of retroperitoneal fibrosis (Fig. 2). There was no evidence of malignancy or tuberculosis. The patient was started on prednisolone 60 mg once daily and tamoxifen 20 mg once daily. After 3 months, the stents were replaced and the dose of prednisolone reduced to 10 mg once daily in a tapered manner. The patient was symptom-free and had normal renal functions, with marked reduction in the size of the mass at 9 months (Fig. 3). At 1 year of follow up, DJ stents were removed. Tamoxifen has been stopped and the dose of prednisolone is now 5 mg once daily.
Classical idiopathic retroperitoneal fibrosis, also known as Ormond's disease, was described in 1948.1 The typical retroperitoneal fibrosis is a fibrotic process encasing the abdominal vessels and the ureter with an epicenter at the level of L4–5.2 RPF has an inciting agent in one-third of the cases, while the remaining two-thirds have no known cause.2 RPF mimicking renal malignancy has been reported.3 There has been only one reported case of renal infiltration reported by Paull et al. who described a dense white fibrous mass completely surrounding the kidney and partially the spleen as perinephritis plastica.4 This case, where both kidneys are encased by mass-like fibrous tissue as a component of RPF, has not been described in the literature, thereby resulting in a diagnostic dilemma. The most common form of secondary RPF is drug-induced, especially by methysergide.5 The other possible causes are tumors, infections, trauma and irradiation. Pathologically, RPF is said to have two stages in its evolution: an inflammatory and a quiescent phase. Steroids have been cited to decrease the progression of fibrosis, particularly in the inflammatory phase.2 Tamoxifen has a non-specific effect of reducing the fibrotic mass, akin to its efficacy in desmoid tumor.6 Surgical intervention is needed in cases of established fibrosis with obstructive uropathy. Ureterolysis and omental wrapping is the most preferred procedure.7 A variety of substances like polytetraflouroethylene, dura, and fat have all been used for ureteral protection.8 Our patient did well with the combined approach and is on a maintenance dose of 5 mg prednisolone at the end of 1 year. The duration of medical therapy is debated, and consensus has been lacking in this regard.9 These patients need to be on life-long follow up, and repeated interventions may be needed in a good number of cases.