Clinical Images: Marked edema of the left lower leg caused by IgG4 ‐related retroperitoneal fibrosis accompanied by double inferior vena cava

The patient, a 75-year-old Japanese man with edema of the left lower leg, was admitted to our hospital (A). Physical examination revealed no abnormal findings other than edema of the left lower leg. Laboratory test results showed a significant elevation in IgG4 (441 mg/dL). Contrast-enhanced computed tomography (CT) revealed perivascular opacities, retroperitoneal soft tissue lesions, and a double inferior vena cava (DIVC) (B). Additional evaluation using 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography–CT revealed 18F-FDG accumulation in the arteries, retroperitoneal soft tissue, lymph nodes, and pleura (C). Lymphoscintigraphy suggested lymphostasis at the left waist (D). Vascular ultrasonography revealed constriction of the left common iliac vein with increased maximum velocity (2.4 m/s) (E). Based on these findings, coexistence of IgG4-related retroperitoneal fibrosis and DIVC was suspected. We conclude that anatomic characteristics of DIVC exacerbated the left lower leg edema by amplifying venous compression caused by IgG4-related retroperitoneal fibrosis. After initiation of prednisolone (initial dose: 30 mg daily), maximum velocity of the left common iliac vein decreased from 2.4 to 0.4 m/s, and edema in the left lower leg improved (F). Leg edema associated with IgG4-related retroperitoneal fibrosis has been previously reported.1, 2 On the other hand, DIVC is a rare, but well-recognized anomaly.3 Our case highlights that anatomic variations such as DIVC may significantly modify the clinical presentation of IgG4-related retroperitoneal fibrosis. Clinicians should recognize the importance of assessing individual vascular anatomy in detail when diagnosing and treating IgG4-related retroperitoneal fibrosis. Written informed consent was obtained from the patient for publication of this report. Disclosure form. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.