PMC4727053_01
Axial precontrast computed tomography images demonstrating a large mass with heterogeneous density, measuring 13x12x11 cm in size, which was located at the lower pole of the right kidney. In addition, an enlarged lymph node of 3 cm in diameter, was also noted (white arrow).
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In addition, several enlarged lymph nodes were noticed in the retroperitoneal space, with the biggest node measuring ~3 cm in diameter (Fig. 1).
Postcontrast computed tomography images revealed moderately heterogeneous enhancement. The mass exhibited low density and irregular patchy attenuation, suggestive of necrosis (white arrow).
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Scattered necrosis and calcification were occasionally observed, and the lesion exhibited moderate heterogeneous enhancement during enhanced scanning (Fig. 2).
Microscopically, the tumor was composed of large polygonal epithelioid cells with markedly bizarre atypical mitotic nuclei, while adipose tissue was scarcely observed (hematoxylin and eosin stain; magnification, x200).
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The tumor was composed of large polygonal epithelioid cells with abundant eosinophilic cytoplasm and markedly bizarre atypical nuclei, which were different from conventional AML (Fig. 3).
Immunohistochemical staining demonstrated that the epithelioid cells and spindle smooth muscle cells focally expressed human melanoma black-45 (magnification, x200).
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Inc., Princeton, NJ, USA), anti-desmin (no. ab919901; Abcam, Cambridge, UK) and anti-melan-A (ab187369; Abcam) and counterstained with hematoxylin and eosin (Abcam). Immunohistochemical staining confirmed that the epithelioid cells focally expressed HMB-45 (Fig. 4), and were moderately positive for melan-A and desmin.