PMC4891620_01
Sonographic images of the right kidney. A. Transverse image revealed a markedly hypoechoic mass with lobulation and septations. [Powerpoint Slide] B. Calipers measure a separate renal cyst. Arrows designate hypoechoic mass. [Powerpoint Slide]
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This revealed what appeared sonographically as a markedly hypoechoic mass with lobulation and septations, thought to be a complex cyst (Bosniak 4) (Figure 1).
Benign renal schwannoma. A. Precontrast CT demonstrates a lobulated right renal mass (40 HU) with a small amount of calcification. [Powerpoint Slide] B. Contrast enhanced CT demonstrates enhancement of the right renal mass (66 HU), which remains hypodense to surrounding renal parenchyma. [Powerpoint Slide]
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The mass showed enhancement after contrast administration (66 HU); however, the tumor was hypodense to renal parenchyma on nephrographic phase images (Figure 2).
Follow-up contrast enhanced CT demonstrates slight interval enlargement of enhancing lobulated right renal mass. [Powerpoint Slide]
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CT evaluation 9 months from the initial CT revealed an increase in the size of the right renal mass, which now measured 4.5 x 5.8 cm (Figure 3).
Hemisected nephrectomy specimen reveals a yellow-tan lobulated intrarenal mass, similar to the appearance suggested by CT. [Powerpoint Slide]
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Gross pathological evaluation of the right nephrectomy specimen revealed a well-circumscribed, white-tan to yellow multilobulated mass measuring 7.0 cm in maximal dimension (Figure 4).
Hematoxylin and eosin stained tissue sections of the tumor demonstrate spindle cells in a palisading arrangement consistent with Antoni A pattern of a schwannoma (100x). [Powerpoint Slide]
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Microscopic evaluation revealed a spindle cell neoplasm with two cellular patterns consisting of areas of tightly packed cells (Antoni A pattern) and areas of loosely arranged cells (Antoni B pattern) consistent with schwannoma (Figure 5).
Photomicrograph shows tumor cells are diffusely immunoreactive for S-100 protein. (100x). [Powerpoint Slide]
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