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.