PMC8426085_01
Computerized tomography urography scan showing two tumors in the midportion of the right kidney with distinct radiologic appearances: the external mass (white arrow) is a fat-containing tumor suggesting AML. The internal tumor (black arrow) is solid demonstrating a heterogeneous enhancement pattern.
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Computed tomography (CT) urography (Figure 1) showed two masses in the midportion of the right kidney with distinct radiologic appearances.
Gross examination revealing two different renal masses: the largest mass (black arrow) was encapsulated and firm composed of golden yellow soft areas with hemorrhagic changes. The smaller mass (white arrow) was well defined and had yellowish, glistening cut surface.
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On gross examination (Figure 2), the kidney was slightly enlarged weighing 280 g and measuring 130 x 70 x 65 mm.
Hematoxylin and eosin staining demonstrating as follows. (a) CCRCC composed of nests of cells with clear cytoplasm, surrounded by a network of abundant thin-walled blood vessels. (b) AML composed of aggregates of thick-walled blood vessels, admixed with mature adipose tissue and smooth muscle cells.
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The cells were mainly arranged in sheets and compact nests surrounded by a regular network of thin-walled blood vessels (Figure 3).
Immunohistochemical study of the AML showing the positivity of (a) Melan A, (b) HMB45, (c) H-Caldesmon, and (d) smooth muscle actin.
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