PMC3737620_01
Adult mesoblastic nephroma in a 47-year-old woman. Magnetic resonance imaging showed a complex but predominantly solid heterogeneous left renal mass. (A) T2WI demonstrated a heterogeneous predominantly hypointense mass with interspersed stellate-like hyperintensity, measuring 5.5 cm in diameter. (B) The mass showed isointensity with intratumoral hypointensity stripes on T1WI. Corticomedullary phase (C), nephrographic phase (D), and pyelographic phase arterial phase (E) multiphasic contrast-enhanced MRI scans demonstrated the progressive enhancement feature of the tumor. (F) Photomicrograph (original magnification, x100; hematoxylin-eosin stain) showed complex tumors composed of large cysts, microcysts, tubules, and spindle cells
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F1
T2-weighted imaging (T2WI) demonstrated a heterogeneous predominantly hypointense mass with interspersed stellate-like hyperintensity [Figure 1A]. T1-WI with areas of low signal intensity [Figure 1B]. The lesion presented mild patchy enhancement on the corticomedullary phase (CMP) [Figure 1C] and progressive heterogeneous enhancement on the nephrographic phase (NP) and pyelographic phase (PP) [Figure 1D and E, respectively]. The pathologic diagnosis was an MN [Figure 1F].
PMC3737620_02
MEST in a 46-year-old man with a history of intermittent gross hematuria. Axial CT scan (A-C) showed a complex but predominantly solid right renal mass, herniating into the renal pelvis. The well-defined mass demonstrated marked delayed contrast enhancement. (D) Photomicrograph (original magnification, x100; hematoxylin-eosin stain) showed that the tumor was composed mainly of proliferating spindle cells, with dilating epithelial tubular cells scattered amidst the spindle cells
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F2
A CT scan revealed a well-defined, solid and cystic, mixed attenuation renal mass bulging into the renal pelvis [Figure 2A]. The mass was ovoid and mainly solid, showing heterogeneous attenuation with moderate prolonged enhancement on CMP and NP [Figure 2B and 2C, respectively]. On histological examination, the tumor was composed mainly of proliferating spindle cells, which stained strongly with smooth muscle actin, with variable cellularity and epithelial tubular cells scattered amid the spindle cells [Figure 2D].