PMC446202_01
Gross photograph of the sliced kidney demonstrates the large renal mass occupying the upper pole of the kidney.
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F1
Haematoxylin and eosin stained slides shows the stromal and multinucleated giant cell components of this neoplasm. The inset figure shows an apoptotic giant cell.
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F2
Both the stromal and the multinucleated giant cells appeared morphologically to be highly reminiscent of giant cell tumor lesions of bone (Figure 2). Mitosis and pleomorphism in the giant cells was not easily observed though apoptotic giant cells were easily observed (Figure 2-inset).
Angiolymphatic invasion with nodules of tumor in the perinephic fat.
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F3
The tumor infiltrated widely through the hilar region into the pelvis of the kidney and extended as nodules into the adjacent cortex abutting onto the renal capsule and was also present in the adjacent perirenal fat (Figure 3) However, the tumor was limited externally by the Gerota's fascia.
Hilar lymph node metastasis.
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F4
Staining with CD68 antibodies was strongly positive in the multinucleated giant cells.
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F5
However, staining with CD68 antibodies was strongly positive in the multinucleated giant cells (Figure 5).
Antibodies to Mac387 highlighted the majority of the stromal mononuclear cell component.
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F6
Majority of the stromal mononuclear cell component was highlighted with antibodies to MAC387 (Figure 6).
Malignant multi-nucleated cell studded with primary and secondary lysosomes. (magnification x 12,0000)
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F7
Examination of the giant cells showed the cytoplasm to be filled with numerous vesicles and vacuoles many of which were consistent with primary or secondary lysosomes (Figure 7).
Pseudomicrovilli at the cell surface. (magnification x 24,000)
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F8
These projections/processes did not qualify as true microvilli as they lacked the filamentous core rootlet and did not possess any evidence of secretory granules at the base of these pseudorootlets (Figure 8).
Simple cell junctions (magnification x 38,400)
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F9
Simple cell matrix junctions were observed but no true desmosomes were identified (Figure 9).
Intracytoplasmic collection of whorled filaments of vimentin (magnification x 30,000)
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F10
Some cells showed the presence of intracytoplasmic accumulation of unusual filaments many of which were in a well-defined curving and somewhat rolled appearance in keeping with vimentin type of intermediate filaments (Figure 10).