PMC6243327_01
(a) Coronal half-Fourier acquisition single-shot turbo spin-echo (echo time 81 ms, repetition time 1000 ms) image of a 32-year-old female with Crohn's disease shows the lesion is hypointense compared to normal renal parenchyma, except for a small isointense focus (arrow). (b) Coronal contrast-enhanced T1image (echo time 1.4 ms, repetition time 3.8 ms) shows enhancing septa around the non-enhancing elements, giving a honeycomb-type appearance. (c, d) The mass has high signal on b800 diffusion weighted imaging and low signal on the apparent difffusion coefficient map.
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fig1
T2 half-Fourier acquisition single-shot turbo spin-echo and true fast imaging with steady-state free precession images (Figure 1). The mass was isointense on pre-contrast T1 volumetric interpolated breath-hold examination and following contrast showed a honeycomb-type appearance with irregular enhancing septa around small non-enhancing elements that measured between 1 and 5 mm (Figure 1). The lesion had restricted diffusion and there was no abnormality within the perinephric fat or renal vessels (Figure 1).
Coronal CT scan of a 31-year-old female with Crohn's disease shows the left renal mass is homogeneously hypoenhancing in the arterial phase (a) and demonstrates patchy enhancement in the portal venous phase (b) with some hypodense internal foci.
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fig2
No calcification or adenopathy was seen (Figure 2).
A B-mode longitudinal ultrasound image showing a homogeneous hypoechoic mass (arrow) bulging the renal contour (a) with no appreciable internal flow on Doppler (b).
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fig3
Sonographically, the mass was slightly hypoechoic and had no demonstrable vascularity (Figure 3).
(a) The core of kidney parenchyma shows a few preserved medullary renal tubules (asterisk). The remainder of the core shows a dense mixed chronic inflammatory cell infiltrate with two foci of granulomatous inflammation with focal necrosis (arrows). Haematoxylin and eosin stain, original magnification x40. (b) Higher magnification of the boxed part of image (a) shows some palisaded histiocytes with an area of necrosis (asterisk). No polarizable foreign material is present. Special stains for organisms (periodic acid-Schiff and Ziehl-Neelsen) were negative. Haematoxylin and eosin stain, original magnification x200.
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fig4
Special stains for organisms, including periodic acid-Schiff and Ziehl-Neelsen, were negative and there were no features of malignancy (Figure 4).
Axial CT scan in the portal venous phase shows a small focus of residual scarring in the left renal inferior pole (arrow) 6 months post initiation of prednisilone treatment.
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fig5
A tentative diagnosis of an inflammatory pseudotumour was made and a course of 30 mg daily of prednisolone was commenced, resulting in resolution of the lesion, with only a small focus of scar present on follow-up ultrasound and CT imaging performed in October 2012 (Figure 5).