Inflammatory pseudotumor of the kidney with renal artery penetration

Abstract

Inflammatory pseudotumor (IPT) is a quasineoplastic lesion that most commonly involves the lung and the orbit; kidney involvement is rare. We report a case of inflammatory pseudotumor of the kidney. The patient was a 61-year-old man who presented with no symptoms. Nonenhanced computed tomography (CT) demonstrated an ill-defined, isodensity mass measuring 3.5 cm in the lower portion of the left kidney. Contrast-enhanced CT showed that branches of the renal artery without encasement penetrated the tumor; there was a little enhancement in the mass on the arterial phase and homogeneous enhancement on the venous phase. On magnetic resonance imaging the mass showed intermediate signal intensity on T1-weighted images (T1WIs) and low signal intensity on T2WIs. Most IPTs of the kidney appear as an ill-defined, hypovascular, homogeneous tumor on CT images, with variable signal intensity on MRI T1WIs and low signal intensity on T2WIs. Our case had the same imaging findings, with branches of the renal artery penetrating the tumor. If the renal tumor has these radiological findings, the tumor may be IPT.

Inflammatory Myofibroblastic Tumor of the Kidney and Bilateral Lung Nodules in a Child Mimicking Wilms Tumor With Lung Metastases

“…2,6,7 The clinical findings of renal IMT include flank pain, hematuria, fever, growth retardation, weight loss, microcytic hypochromic anemia, and thrombocytosis. However, it may be asymptomatic without any signs.…”

Mass in failed renal allograft: Answers

“…Although we did not proceed with magnetic resonance imaging (MRI), this modality is similar to contrast-enhanced CT. IMTs typically appear as low signal intensity on T2-weighted images and highly variable on T1-weighted images [10]. This modality is less attractive in the setting of any renal dysfunction given the gadolinium-associated nephrogenic systemic fibrosis [11].…”

Bilateral renal inflammatory pseudotumour effectively treated with corticosteroid

“…US of IPT in other locations has demonstrated a variable pattern of echogenicity with illdefined or well-circumscribed margins. On CT scanning, renal IPT can appear as a mass showing low attenuation, and delayed enhancement has been observed, probably because of the accumulation of extravascular contrast media in the fibrotic component of the lesion [21]. However, there is considerable heterogeneity in the CT appearance of these lesions.…”

“…However, there is considerable heterogeneity in the CT appearance of these lesions. Renal IPT on MRI usually displays itself as a variable signal intensity lesion on T1-weighted images and low signal intensity on T2-weighted images [21]. The preoperative recognition of renal IPT is important to avoid unnecessary nephrectomy especially in the setting of bilateral involvement where nephrectomies would render the patient anephric and dialysis dependent.…”

“…Differential diagnosis of renal IPT may include renal cell carcinoma (RCC), transitional cell carcinoma of the renal pelvis, malignant lymphoma, xanthogranulomatous pyelonephritis and angiomyolipoma with minimal fat [21]. Current radiological modalities will detect a mass lesion or an enlarged kidney but have limited utility in differentiating between IPT and other malignant tumours.…”