A case of immunoglobulin G4-related inflammatory pseudotumor mimicking renal cell carcinoma

Journal Article · Mon Apr 01 04:00:00 EDT 2019 · Abdominal Radiology (Online)

DOI:https://doi.org/10.1007/S00261-018-01885-1· OSTI ID:22923050

Watanabe, Hiroshi ^[1]; Tanaka, Hajime; Fujii, Yasuhisa ^[2]; Kodama, Makoto; Akashi, Takumi ^[3]; Fujioka, Tomoyuki; Kubota, Kazunori; Saida, Yukihisa; Tateishi, Ukihide ^[1]

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1. Tokyo Medical and Dental University, Department of Diagnostic Radiology (Japan)
2. Tokyo Medical and Dental University, Department of Urology (Japan)
3. Tokyo Medical and Dental University, Department of Comprehensive Pathology (Japan)

In a 69-year-old woman with a history of Mikulicz’s disease, a hypoechoic solitary renal mass was identified on routine ultrasound examination. Based on the findings of computed tomography (CT) and magnetic resonance imaging (MRI), renal cell carcinoma was a possible diagnosis. Subsequent partial nephrectomy revealed a mass characterized by an increased number of blood vessels, internal hemorrhage, and a thick fibrous capsule. Immunohistochemically, the mass comprised of tubulointerstitial nephritis with increased immunoglobulin (Ig)G4-positive plasma cells and fibrosis. Generally, diagnosis of IgG4-related kidney disease (IgG4-RKD) is not difficult when the kidney is involved together with other systemic involvements. However, diagnosis becomes harder when a solitary renal mass appears as a single-organ involvement. On precise review of our imaging findings, MRI signals were markedly affected by hemorrhage, so the mass showed hypointensity on both T1- and T2-weighted imaging, and the signal of in-phase images decreased. Dynamic MRI showed no apparent enhancement of the mass, while CT showed an apparent enhancement effect. Capsule formation was another key finding for IgG4-RKD and was recognized as a gradually enhancing boundary zone surrounding the mass on both CT and MRI. When a solitary renal mass is associated with hemorrhage and thick capsule formation, inflammatory pseudotumor should be considered as differential diagnosis.

• OSTI ID: 22923050
• Journal Information: Abdominal Radiology (Online), Journal Name: Abdominal Radiology (Online) Journal Issue: 4 Vol. 44; ISSN 2366-0058
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BLOOD VESSELS
CAPSULES
CARCINOMAS
COMPUTERIZED TOMOGRAPHY
DIAGNOSIS
HEMORRHAGE
IMMUNOGLOBULINS
KIDNEYS
NEPHRECTOMY
NEPHRITIS
NMR IMAGING
PLASMA CELLS
WOMEN