Radical nephrectomy for retroperitoneal fibrosis: Case report

Abstract

Introduction and importance

Retroperitoneal fibrosis is a proliferative disease of fibroblasts with a still unclear appearance and low incidence. The clinical manifestations are nonspecific and appear late, pain is the most common symptom present. Elevated serum IgG4 levels are observed in up to 60 % of the patients and the main goal of treating this condition is to preserve kidney function.

Case presentation

We present a case of an asymptomatic 34-year-old man. A poorly defined mass in the pre-aortic, pre-caval and right rim regions with possible malignancy was observed. After 3 biopsies, it was treated as low-grade follicular lymphoma with chemotherapy. With new growth after 1 year, right radical nephrectomy was performed to resect the lesion. Pathology showed that it was advanced retroperitoneal fibrosis with negative IgG4.

Clinical discussion

RPF usually presents as an irregular mass of periaortic tissue that frequently has malignancy as a risk factor and may be associated with high levels of IgG4. Most of the time, the disease is asymptomatic. When the patient presents symptoms, pain is the most common, although late. Its diagnosis is made by imaging and histopathological exams. Treatment varies according to the progression of the disease, but aims to try to preserve renal function.

Conclusion

RPF is a disease characterized by the accumulation of fibroblasts in the abdominal region with an etiology that has not yet been fully discovered, which can present in several ways, generally identified by imaging exams and can be treated individually depending on the invasiveness of the disease.

Highlights

• •Retroperitoneal fibrosis is characterized by the accumulation of fibroblasts in abdominal region
• •The main goal of treating RPF is to preserve kidney function
• •The clinical manifestations of RPF are nonspecific and appear late. Pain is the most common symptom
• •Our case presents an asymptomatic mass, that after 3 biopsies was treated as lymphoma with chemotherapy. With new growth after 1 year, the lesion was removed by radical nephrectomy.

1. Introduction

Retroperitoneal fibrosis (RPF) is a rare disease described by a fibrotic and inflammatory tissue involving the aorta and its main branches, also referred to as periaortitis/periarteritis, an expansile mass of soft tissue in the renal pelvic wall and/or around the ureter, and placoid lesions in the pelvis and paravertebral area [1].

The annual incidence of idiopathic RPF is estimated at 0.1/100,000 people per year. The main risk factors are exposure to asbestos or tobacco, which almost quadruples the risk of developing the disease. Furthermore, HLA-DRB3 may have a potential pathogenetic involvement in susceptibility to RPF [2].

Sometimes, this fibrotic mass may contain areas of fibrinoid necrosis, lymphocytic infiltrations (B and T lymphocytes), epithelial structures or giant cells, which suggest sarcoidosis [3], demonstrating the complexity in making the diagnosis.

The goal of medical therapy is to control local expansion of fibrotic tissue and resolve ureteral obstruction, if present. In this case, the first-line approach involves the use of an intraureteral stent or nephrostomy [1]. The work has been reported in line with the SCARE criteria [4].

2. Case

A 34-year-old male, black, CrossFit athlete, asymptomatic, user of anabolic steroids, when undergoing routine exams to maintain health and prepare for a competition, it was revealed on ultrasound and later on computed tomography, a poorly delimited tissue in the pre-caval and pre-aortic regions and in focal areas of the right kidney with possible malignancy. Then, 3 biopsies were performed by core biopsy technique in the anterior right kidney across polar line, with immunohistochemistry, which showed dense fibrosis and small cell infiltrate with a lymphoid pattern, predominantly made up of B cells, with positive expression of CD 3, 10, 20 and 23, Bcl-2 and Bcl-6. and negative for CD 34 and IgG4, favoring the diagnosis of low-grade follicular lymphoma.

As a result, chemotherapy was performed in R-CHOP regimen in 3 cycles with PET-CT monitoring every 3 months, progressing with regression of the lesions and leaving only a residual mass in the right kidney. However, one year later, the examination demonstrated a progressive and invasive growth of this mass in the kidney, right adrenal and retroperitoneum, suggesting lymphoproliferative neoplasm activity (Fig. 1, Fig. 2).

Fig. 1.

PET CT.

The arrow indicates amorphous, slightly hyperattenuating tissue partially occupying the sinus and right hilum in continuity with the retroperitoneum.

Fig. 2.

PET CT.

Signs of right nephropathy (arrow). Left renal parenchyma without alterations.

So, with the recurrence of the mass, the patient underwent right radical nephrectomy, finding a retroperitoneal lesion of undetermined cellularity, adherent to the cava and aorta, which was successfully resected, with no postoperative complaints. In the anatomopathological examination, the specimen measuring 9.4 × 6.9 × 4.2 cm showed extensively hyalinized hypocellular fibrosis affecting the renal parenchyma, collecting system, hilar vessels, ureter, perirenal fat and right adrenal, with foci of discrete lymphoplasmacytic inflammatory infiltrate, extensively destroying the renal parenchyma and involving the ureter, promoting marked stenosis, without malignancy, being considered the diagnosis of retroperitoneal fibrosis in an advanced phase of dense fibrosis, with negative immunohistochemistry for CGA-7, B catenin, IgG4, Ki- 67 and S-100 (Fig. 3, Fig. 4). The patient remained asymptomatic, was discharged on the 2nd postoperative day, without pain, walking, urinating normally, without complaints and without relapses to date, with good recovery.

Fig. 3.

Macroscopic examination.

Right radical nephrectomy product measuring 9.4 × 6.9 × 4.2 cm showing a large, firm, whitish area, compromising the renal parenchyma, hilum and peri-renal tissue (arrow).

Fig. 4.

Microscopic examination.

Arrows show extensively hyalinized fibrosis replacing renal tissue from the hilum, associated with parenchymal atrophy.

3. Discussion

Although the emergence of retroperitoneal fibrosis is still unclear, malignancy is often listed as a risk factor or a secondary form of RPF. Its pathogenesis is a metastatic disease in the retroperitoneal space, producing a surrounding inflammatory and fibrotic reaction. The most common cancers found in the retroperitoneal space are lymphomas and cancers of the urinary tract [5]. In the present case, a poorly delimited tissue was documented with a favorable diagnosis of low-grade follicular lymphoma in the pre-caval and pre-aortic region, suggesting the pathogenesis of this case.

Regarding location, the typical presentation is an irregular mass of periaortic tissue that extends from the level of the renal arteries to the iliac vessels, progressing to the retroperitoneum and involving the ureters and inferior vena cava [5]. The patient in question had a mass equivalent to the typical appearance of RPF, with lesions adhered to the cava and aorta, destroying the renal parenchyma and involving the ureter, causing stenosis.

The clinical manifestations of RPF are nonspecific and appear late. Pain is the most common symptom present and is described as deep in the abdomen, affecting one or more flanks and radiating to the inguinal region. Physical fatigue, weight loss, and digestive discomfort may also be noted. In this clinical context, the diagnosis is established through imaging: ultrasound is a signpost, while computed tomography and magnetic resonance establish the initial/presumptive diagnosis [3,5]. Therefore, the patient did not present any symptoms at first, discovering this lesion in the pre-caval and pre-aortic region at random through routine examinations. The lesion was so large that it suggested a neoplastic process.

In recent years, there has been a focus on the IgG4-associated RPF theory. Furthermore, elevated serum IgG4 levels are observed in up to 60 % of patients with RPF. Likewise, another study emphasized the fact that the symptoms of patients with and without positive histology do not differ and that the IgG4/total IgG ratio is the method of choice with greater sensitivity in contrast to histology [6]. Though, in the case exposed, immunohistochemistry revealed a negative IgG4 marker, but with anatomopathological examination, extensive fibrosis, affecting the retroperitoneal region. Regarding biopsy techniques, core biopsy is used in most cases and facilitates diagnostic resolution.

The main goal of treating RPF is to preserve kidney function. Lesions without urinary tract obstruction or renal failure can be treated only with medical therapy, with glucocorticoids being the clinical therapy of first choice. Patients with acute renal failure, or at least moderate obstructive uropathy on imaging, require ureteral drainage using ureteral stents or nephrostomies. Surgery can be used in refractory cases, when there is hydronephrosis or obstructions or in those with reduced renal parenchyma [1]. As in this case there was a progressive and invasive growth of the mass towards the right kidney, with destruction of the renal parenchyma, a robotic-assisted right radical nephrectomy was chosen, with good postoperative evolution of the patient without complaints or recurrences of this condition.

4. Conclusion

Retroperitoneal fibrosis is an entity characterized by the accumulation of fibroblasts in the abdominal region, which may or not be related to malignancy. It can be asymptomatic, with pain or obstructions. Its diagnosis is made through imaging tests and treatment varies according to the invasiveness of the disease, from corticosteroids to surgical approaches.

Consent

Written informed consent was obtained from the patient for publication and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

Ethical approval for this study was provided by the Ethical Committee on July, 28th 2023. A copy of this approval is available for review by the Editor-in-Chief of this journal on request.

Guarantor

Fernando Oliveira dos Santos.

Research registration number

This case report is not a first time of reporting, new device or surgical technique. So it would not need a Research Registry Unique identifying number (UIN).

Funding

There are no sources of funding.

Author contribution

Matheus Miranda Paiva: Conceptualization; Supervision; Validation; Writing – review & editing.

Eloi Guilherme Provinciali Moccelli: Writing – review & editing.

Alessandro Vengjer: Supervision; Writing – review & editing.

Guilherme Henrique Silveira Stiirmer: Conceptulization; Data curation; Investigation; Writing – review & editing.

Fernando Oliveira dos Santos: Conceptualization, Investigation; Writing – original draft.

Paulo Peixoto do Nascimento: Investigation; Writing – original draft.

Conflict of interest statement

The authors declare that they have no competing interests.