Retroperitoneal fibrosis secondary to non-urology carcinomas: a clinical and outcome analysis of 97 cases

New-onset retroperitoneal fibrosis following COVID-19 mRNA vaccination: Coincidental or vaccine-induced phenomenon?

The Pfizer-BioNTech mRNA vaccine is a US Food and Drug Administration-approved coronavirus disease 2019 (COVID-19) vaccine. Although it is reported to be safe and effective, immune dysregulation leading to autoimmunity has become an area of concern. Retroperitoneal fibrosis (RPF) is an immune-mediated fibroinflammatory disease characterized by the deposition of fibrous tissues, primarily around the abdominal aorta and iliac arteries. Herein, we report a case of RPF following Pfizer BioNTech COVID-19 mRNA vaccination. To the best of our knowledge, there have been no published reports on RPF after COVID-19 mRNA vaccination. A 58-year-old woman with no history of autoimmune diseases presented with acute onset of epigastric pain 5 weeks after the second dose of the Pfizer-BioNTech vaccine. She had been diagnosed with stage I breast cancer 9 years ago and was in complete remission on admission. Abdominal computed tomography showed preaortic soft-tissue infiltration around the origin of the superior mesenteric artery but no evidence of breast cancer recurrence. Considering the temporal relationship between current symptoms and vaccination and the absence of other possible causes, she was diagnosed with RPF secondary to Pfizer-BioNTech vaccine-induced autoimmunity. This case may raise awareness of the possibility of RPF development following COVID-19 mRNA vaccination.

Association of retroperitoneal fibrosis with malignancy and its outcomes

INTRODUCTION

Retroperitoneal fibrosis (RPF) is characterized by a highly fibrotic retroperitoneal mass and encompasses the idiopathic form and secondary to malignancies. Because we have limited knowledge whether RPF is associated with malignancy, we aimed to investigate the relationship between RPF and malignancy and to compare the characteristics and prognosis of cancers among patients with RPF.

METHODS

Medical records of 111 patients diagnosed as having RPF were reviewed and 38 cases of cancer, confirmed by biopsy, were identified. Standardized incidence ratios (SIRs) were calculated for cancers and stratified according to cancer type and RPF-cancer diagnosis interval. Cancer characteristics and outcomes were compared between RPF-cancer diagnosis intervals.

RESULTS

The average age at RPF diagnosis was 59.2 ± 15.0 years, and 69.4% of the patients were male. The cancer SIRs in patients with RPF relative to age- and sex-matched individuals in the general population was 2.2 (1.6-3.1). SIRs of renal pelvis cancer and multiple myeloma were significantly higher than in the general population. When stratified by RPF-cancer intervals, the SIR for cancer was 9.9 within 1 year of RPF diagnosis, while no significant increase in the SIR was found after 1 year from RPF diagnosis. Cancer stage was more advanced at the time of diagnosis in patients within a 1-year interval for RPF than those with cancer within a >5-year interval, with a correspondingly increased mortality in the former patients.

CONCLUSIONS

RPF was significantly associated with malignancy, particularly those diagnosed within 1 year of RPF diagnosis. Cancer stages at diagnosis were more advanced and the mortality rate was higher in patients within a 1-year interval between RPF and cancer diagnosis than in those with a >5-year interval between diagnoses.

Current approach to diagnosis and management of retroperitoneal fibrosis

Retroperitoneal fibrosis is characterized by fibrotic lesions around the abdominal aorta and common ileac artery causing ureteral obstruction. Secondary retroperitoneal fibrosis is associated with malignant disease, drugs, exposure to radiation and surgery. In contrast, the majority of retroperitoneal fibrosis is classified into idiopathic retroperitoneal fibrosis, for which immunological etiology has been suggested. Recently, idiopathic retroperitoneal fibrosis has been considered to be a spectrum of immunoglobulin G4-related disease, a systemic inflammatory disease, the concept of which has been developed during the past decade. In the management of retroperitoneal fibrosis, assessment of systemic lesions associated with immunoglobulin G4-related disease and the exclusion of secondary retroperitoneal fibrosis is mandatory. Histological examination of retroperitoneal lesions is desired for accurate diagnosis and management. Laparoscopic or open biopsy is often beneficial, although it is more invasive than needle biopsy. Treatment for idiopathic retroperitoneal fibrosis consists of meticulous glucocorticoid therapy based on that for immunoglobulin G4-related disease, which is expected to be highly effective. Ureteral obstruction is usually managed with conservative procedures, such as ureteral stenting or percutaneous nephrostomy. The goal of treatment for retroperitoneal fibrosis should be freedom from the stent/nephrostomy with withdrawal of the glucocorticoid in addition to salvage of renal function; however, conservative management does not always provide favorable outcomes. In contrast, aggressive surgical treatment, such as ureterolysis, can achieve the goal; however, the procedure is associated with high morbidity. Establishment of a consensus about treatment for idiopathic retroperitoneal fibrosis, including the optimal indications for the invasive surgical procedure and conservative management, is desired.