PMC9713829_01
Lesion as observed using magnetic resonance imaging. (A) Frontal plane and (B) sagittal plane. The images indicate an incidentally revealed pathologic lesion of the left kidney (hollow arrow) containing a small solid component adjacent to its wall (filled arrow). The lesion is well-demarcated and shows high signal intensity on T2-weighted imaging.
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T2-weighted imaging but no contrast enhancement (Fig. 1).
Lesion as observed using multiphase computer tomography scans. The present study confirmed the presence of the lesion in the upper pole of the left kidney (empty arrow). (A) Native phase. The cystic lesion shows low intensity and nonsignificant contrast enhancement in both (B) early and (C) late arterial phases, as well as in (D) delayed phase. There is a small contrast-enhancing tumor visible adjacent to the cystic wall (filled arrow).
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The presence of the lesion was then confirmed on multiphase abdominal computed tomography (CT) scan (Fig. 2). The attenuation of the lesion on native-phase images was 30
Cystic component of the mixed epithelial and stromal tumor. Hematoxylin-eosin staining (magnification, x40).
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Microscopically, appearance of the cystic component of the tumor resembled an adult cystic nephroma (Fig. 3).
Solid component of the mixed epithelial and stromal tumor. Branched glandular structures of smooth-muscle-like bundles covered with cuboidal epithelium. Hematoxylin-eosin staining (magnification, x40).
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The stromal component contained elongated spindle-shaped smooth muscle-like cells with vesicular nuclei surrounded by hypocellular highly collagenized matrix with flattened vessels (Fig. 4).
Sample of tumor. Small, scattered tubular structures, lined with transitional cells with amphiphilic or clear cytoplasm, with eosinophilic secretions inside the tubules. Hematoxylin-eosin staining (magnification, x100).
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Eosinophilic secretions were seen inside the tubules (Fig. 5).
Segment of neoplasm. Tumor pattern (black hollow arrow) and the borders of the tumor (double arrow). Collecting ducts are marked with a black filled arrow. Hematoxylin-eosin staining (magnification, x40; scale bar, 10 microm).
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Some of the tubules were protruding among the papillary ducts (Fig. 6).
Positive staining for estrogen receptors within the mixed epithelial and stromal tumor stroma (magnification, x100).
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The stromal cells were, immunohistochemically, positive for ER [Dako, catalog number IR084 RTU, 30'Ab, room temperature] (Fig. 7), PgR [Dako IR068 RTU, 30'Ab, room temperature], SMA [Dako IR611 RTU, 30'Ab, room temperature] (Fig. 8) and caldesmon.
Positive staining of the mixed epithelial and stromal tumor epithelium with paired box gene 8 antibody (magnification, x100).
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The epithelial component was positive for GATA-3 [Ventana L50-823, 30'Ab, room temperature] and PAX-8 [Cell Marque MRQ-50, 30'Ab, room temperature] (Fig. 9).