SHM Converge Scientific Abstract ePoster Gallery-Lymphadenopathy and Extensive Thrombosis as the Initial Presentation of Idiopathic Retroperitoneal Fibrosis

Pdf Summary

This case describes a previously healthy 23-year-old man training for an ultramarathon who presented with acute progressive low back pain, fever, and night sweats. Initial imaging at an outside hospital showed extensive retroperitoneal, mesenteric, and retrocrural lymphadenopathy, a retroperitoneal mass, and bilateral iliac vein deep vein thromboses extending into the inferior vena cava. He was transferred for further evaluation and was also found to have acute bilateral pulmonary emboli.<br /><br />Because the presentation strongly suggested malignancy, he underwent a broad work-up. Infectious, rheumatologic, and oncologic testing was largely negative. PET/CT showed a retroperitoneal mass with only low-level FDG uptake and no clear hypermetabolic disease. Multiple biopsies, including lymph node sampling and diagnostic laparoscopy with biopsy of the retroperitoneal mass and mesenteric nodes, revealed benign fibroinflammatory tissue with granulation tissue and no malignancy or abnormal flow cytometry.<br /><br />With cancer and other causes excluded, the final diagnosis was idiopathic retroperitoneal fibrosis (IRF), an uncommon immune-mediated fibroinflammatory disorder that usually affects the retroperitoneum but rarely presents with major thrombotic complications. The patient was treated with prednisone, rituximab, anticoagulation, and IVC/iliac vein thrombectomy. He later required repeat thrombectomy and bilateral iliac stent placement for persistent venous obstruction and edema. He continues follow-up and intermittent rituximab therapy.<br /><br />The key lesson is that IRF can mimic malignancy by causing B symptoms, lymphadenopathy, and hypercoagulability, making diagnosis challenging and often requiring exclusion of other etiologies through extensive evaluation and biopsy.

Asset Subtitle

Ariel Davydov

Meta Tag

Author List Ariel Davydov, David Chen, Madeline Labor, S. Lindsey Davis

Category Clinical Vignettes

Concept Retroperitoneal Fibrosis

Concept Differential Diagnosis

Concept Malignancy

Concept Diagnosis of Exclusion

Concept Retroperitoneal Mass

Distinguished Non-Finalist

Presenter Organization University of Colorado Anschutz School of Medicine

Presenting Author Ariel Davydov

Track Adult

Keywords

idiopathic retroperitoneal fibrosis

retroperitoneal mass

lymphadenopathy

deep vein thrombosis

pulmonary embolism

fibroinflammatory disorder

malignancy mimic

biopsy

rituximab

anticoagulation

Retroperitoneal Fibrosis

Differential Diagnosis

Malignancy

Diagnosis of Exclusion

Retroperitoneal Mass