PMC5494058_01
Computed tomography (CT) scan of the abdomen. (a) Axial section and (b) coronal section showing a well-defined heterogeneous lesion measuring 2 x 1.5 cm located at the posterolateral upper pole of the left kidney, most likely arising from kidney cortex.
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fig1
These findings suggested renal cell carcinoma (Figure 1).
(a) Low-power view of multilobular growth pattern with lobules containing markedly expanded vascular spaces; the lobules are separated by fibrous bands (H&E; x40). (b) Well-demarcated but uncapsulated tumor demonstrating large gaping vascular spaces surrounded by clusters of glomus cells (H&E; x100). (c) Tumor cells exhibiting nodular growth pattern, no necrosis seen (H&E; x100). (d) Sheets and nests of bland cells with oval nuclei with stromal hyalinization (H&E; x200). (e) Focal areas adjacent to the vascular spaces show solid glomus tumor, consisting of nodules of bland small round to oval monotonous cells with low mitosis (H&E; x100). (f) Round to ovoid glomus cells with hypercellularity and distinct cell borders, each containing a single centralized, uniform, round, small "punched out" nucleus (H&E; x400). (g) Glomus tumor forming trabeculae in abundant myxoid areas (H&E; x200). (h) Small, round, uniform, and with pale eosinophilic to amphophilic cytoplasm (H&E; x400).
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Microscopic examination reveals a well-demarcated lesion composed of sheets of cells that were admixed with large, gaping, dilated cavernous-like spaces filled with blood (Figures 2(a) and 2(b)). These cells are monotonous, small, and round to oval, each containing a moderate amount of eosinophilic to amphophilic cytoplasm (Figures 2(e) and 2(f)). There was no evidence of necrosis (Figure 2(c)) or increased mitotic activity of more than 2/50 high-power field (HPF) (Figure 2(d)). High-power examination showed small nuclei with fine chromatin (Figure 2(f)) and smooth nuclear membrane embedded in a myxoid stroma (Figures 2(g) and 2(h)); other adjacent areas revealed hyalinized stromal reaction (Figure 2(d)).
(a) Immunohistochemistry of the tumors cells shows strong and diffuse positivity for alpha smooth muscle actin (alpha-SMA) (H&E; x200). (b) Nicely uniform pericellular positivity for type IV collagen (H&E; x200).
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Tumor cells showed diffuse and strong positivity for smooth muscle actin (alpha-SMA) (Figure 3(a)), vimentin, and pericellular net-like positivity for collagen type IV (Figure 3(b)).