Pathologically Proven Spontaneous Remission of IgG4-related Retroperitoneal Fibrosis

[SIGNIFICANCE OF IgG4 IN IDIOPATHIC RETROPERITONEAL FIBROSIS]

(Objective)Retroperitoneal fibrosis is largely divided into the idiopathic and secondary types. Some idiopathic cases include IgG4-related diseases, which are often similar to malignant diseases, such as lymphoma and sarcoma. The diagnostic criteria for IgG4-related disease are used and pathologic examination is necessary for a definitive diagnosis of IgG4-related retroperitoneal fibrosis. The first choice of treatment for IgG4-related retroperitoneal fibrosis is steroid administration, but no consensus has been established regarding its dose and tapering schedule. We investigated the significance of IgG4 in diagnosis and treatment of idiopathic retroperitoneal fibrosis. (Patients and methods)We examined 14 cases diagnosed as idiopathic retroperitoneal fibrosis between April 2013 and March 2019. Serum IgG4 was measured at the time of diagnosis in 13 cases, and changes over time in serum IgG4 before and after the induction of steroid therapy were measured in 6 cases. Computed tomography-guided biopsy was performed on 4 cases. (Results)Of all cases, 1 patient was diagnosed as IgG4-related retroperitoneal fibrosis and 5 patients were classified as possible group. Ten patients were administered steroid therapy. Percutaneous nephrostomy tube was placed in 3 patients and was removed in 2 of these patients after steroid therapy. The serum high levels of IgG4 were confirmed in all 4 patients who were classified into the possible group and who were treated with steroids. (Conclusion)Although histologic examination is necessary for the diagnosis of retroperitoneal fibrosis, tissue collection by open or laparoscopic surgery is highly invasive. CT-guided biopsy may be useful in high-risk cases, such as elderly patients on anticoagulation. After excluding other diseases in high-risk cases, response to empiric steroid therapy may be diagnostic. In the possible group, changes in serum IgG4 levels may reflect the disease condition and might be useful in determining the maintenance dose of steroids.

Remission of "mistletoe sign" after treatment

We described a 55-year-old man, in whom the first manifestation of retroperitoneal fibrosis (RPF) was only coronary arterial involvement, which had no periaortic or peri-iliac and urinary system retroperitoneum involvement in general and other systemic clinical manifestations. Coronary manifestation was called "mistletoe sign" on the images. Here, we report a case of IgG4-related RPF remission that was only coronary arterial involvement after treatment.

Idiopathic Retroperitoneal Fibrosis Presenting as Low Back Pain

Retroperitoneal fibrosis is a rare condition characterized by the presence of fibrous inflammatory tissue in the retroperitoneal structures, such as the infrarenal great vessels and ureters. We are reporting an atypical case of an alcoholic who presented with chronic back pain and abnormal liver function tests. Abdominal imaging revealed an incidental, ill-defined, abnormal soft tissue mass in the left pelvis and mild to moderate left hydroureteronephrosis. Interventional radiology (IR)-guided core biopsy reported cores of dense fibrous tissue with extensive lymphoplasmacytic infiltrates, consistent with idiopathic retroperitoneal fibrosis (IRF). The patient had a left ureteral stent placed and, subsequently, had robotic surgery for ureteral reimplantation.