PMC4802132_01
Sagittal fat saturated T2-weighted magnetic resonance image. A round, well-circumscribed, T2-heterogeneous signal intensity mass (arrow) displaces the anteroinferior urinary bladder inferiorly.
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Magnetic resonance imaging (MRI) confirmed this mass as a well-circumscribed structure abutting the superolateral urinary bladder, with a thin but preserved intervening fat plane between it and the urinary bladder (Fig. 1).
[18F]-Fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) (A) Maximum intensity projection (MIP) image shows innumerable hypermetabolic foci throughout the lungs, osseous structures, and lymph nodes above and below the diaphragm. (B) CT soft tissue window, Fusion PET-CT, and CT bone window images show the index supravesical lesion with faint FDG uptake (thick arrow). Focal hypermetabolic right iliac bone lesion was also targeted for biopsy revealing sarcomatoid reaction (thin arrow).
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For further staging, [18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) scan was undertaken, demonstrating the index supravesical lesion to be FDG-hypermetabolic, as well as innumerable FDG-hypermetabolic lesions with an osseous, renal, pleural, and lymphatic distribution (Fig. 2).
(A) Histopathology of the suprapubic mass demonstrate a neoplasm composed of cells with clear vacuolated cytoplasm and hyperchromatic small nuclei (H&E, x90). (B) Immunohistochemically, tumor cells show nuclear positivity with PAX8 (IHC stain x150). (C) Immunohistochemically, tumor cells show strong, diffuse positivity with CD10 (IHC stain x150). (D) H&E stained sections of the neddle biopsy from the iliac bone showing granulomatous inflammation (x150).
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Histopathology of the supravesical specimen revealed clear cell RCC (representing delayed isolated omental metastasis) while the osseous specimen was interpreted as sarcomatoid reaction (Fig. 3).
Macroscopic appearance of the omental metastatic deposit. Note its prominent vascular supply and collateral vascular network covering its surface.
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We opted for an open surgery to remove the mass and during exploration it was found to be located within the omentum as a clearly palpable, isolated nodularity (Fig. 4).
Omental tumor has similar histopathologic features with the suprapubic mass, consistent with clear cell renal cell carcinoma (H&E x30).
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Histopathological examination findings in the omental mass were concordant with the tru-cut biopsy result (Fig. 5).