PMC9942222_01
Contrast-enhanced CT scan of the abdomen, axial (a) and coronal (b) sections, showing the large enhancing right renal mass with internal vascularity, replacing almost the entire renal parenchyma
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F1
The contrast-enhanced computed tomography (CECT) scan of the abdomen and thorax revealed a heterogeneously enhancing soft tissue density mass lesion of size 12.6 cm x 13.2 cm x 15.4 cm arising from the right kidney, pushing and compressing the renal cortex, with extension into the right retroperitoneal space displacing the ascending and the transverse colon anteriorly and the small bowel loops and the stomach toward the left side [Figure 1], with suspicious soft-tissue deposits along the left thoracic paravertebral space and in the pericardium along the right atrium.
Right radical nephrectomy specimen (a) Cut Section (b) showing a large tan brown tumor with a thin rim of remaining parenchyma at the upper pole
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F2
The tumor was limited to the Gerota's fascia and the renal vein was free [Figure 2].
Microscopic examination (a) H and E, x40 showing large collections of histiocytes with an enlarged round to oval nuclei and abundant pale staining cytoplasm. These histiocytes are exhibiting emperipolesis (arrow). (b) Immunohistochemistry staining with S-100 at x10, showing positive tumor cells in a background of normal renal tubules
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F3
These histiocytes were exhibiting emperipolesis [Figure 3].