PMC3861592_01
Tumor localized on the upper pole of the left kidney that is (A) heterogeneous with a central lower density and (B) showing heterogeneous attenuation with peripheral enhancement and central irregular non-enhancement.
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No invasion was identified of the ambient structures in the upper pole of the left kidney (Fig. 1A). Enhanced CT showed heterogeneous attenuation with peripheral enhancement and central irregular non-enhancement (Fig. 1B).
(A) Gross appearance and (B) histopathological examination of the resected specimen (hematoxylin and eosin; magnification, x100).
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The gross appearance of the resected specimen of the giant mass showed a well-circumscribed, non-encapsulated, grayish-yellow solid tumor with areas of necrosis in black that measured ~20x13x10 cm3 (Fig. 2A). Histologically, the tumor was composed of spindle-shaped myoid cells with a concentric arrangement of cells around numerous variably-sized blood vessels, and the tumor cells were arranged in nests or fascicles (Fig. 2B).
Immunohistochemically, the tumor cells were diffusely positive for (A) smooth muscle actin and (B) CD10, and (C) had a Ki-67 index of <1%, but were negative for (D) S-100 (magnification, x100).
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Immunohistochemically, the tumor cells were diffusely positive for smooth muscle actin (Fig. 3A), cluster of differentiation (CD)10 (Fig. 3B) and had a Ki-67 index of <1% (Fig. 3C). However, staining was negative for CD34, desmin, S-100 protein (Fig. 3D), cytokeratin, human melanoma black (HMB)-45, B-cell lymphoma (Bcl)-2 and CD99.