PMC6046177_01
Computed tomography (CT) scans revealing a partially visualized, heterogenous enhancing right inguinal mass (arrows).
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A follow-up computed tomography (CT) scan revealed a partially visualized, heterogenous, and enhancing right inguinal mass, raising the concern for a peripheral nerve sheath tumor or sarcoma of the spermatic cord (Figure 1).
(a) Gross photograph of the tumor. The tumor is well-circumscribed with a thin fibrous membrane. (b) The tumor at low magnification, demonstrating the tumor border (H&E, x40).
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The cut surface of the mass was white and firm and had a whorled texture containing occasional small cysts (Figure 2(a)). The margin is inked green (Figure 2(b)).
Microscopic features and immunohistochemical results. (a) Typical hypo- and hypercellular areas of the tumor (H&E, x40). (b) Vessels containing proliferating myocytes associated with complete mural hyalinization (arrow) (H&E, x100). (c) A vessel with mural myxoid degeneration (H&E, x100). (d) Bland looking neoplastic cells with oval to fusiform nuclei and little cytoplasm around hyalinized small vessels (arrow) (H&E, x400). (e) Numerous hemangiopericytoma-like vascular channels (CD34, x100). (f) STAT6 immunostain showing strong diffuse nuclear positivity in the neoplastic cells. The vascular myocytes are negative (STAT6, x200).
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Microscopically, the tumor had a heterogeneous pattern-less architecture with alternating hypocellular and hypercellular areas, interstitial hyalinization, and intermixed with ropy collagen bands (Figure 3(a)). Numerous small- to medium-sized vessels were present and showed a continuum of changes, ranging from thick-walled vessels showing proliferation of myocytes, to vessels revealing intimal thickening, to vessels with circumferential prominent mural hyalinization (Figure 3(b)). Some of the larger vessels displayed subendothelial mucoid degeneration resembling vascular changes observed during accelerated hypertension (Figure 3(c)). Occasional individual exuberant hemangiopericytoma-like vascular channels were also present (Figure 3(d)). The neoplastic cells were ovoid to spindle-shaped with scanty pale cytoplasm and oval to fusiform nuclei (Figure 3(e)). Actin (SMA) and S100. A STAT6 stain was ordered and revealed nuclear positivity in the tumoral cells but negative staining in the vascular myocytes (Figure 3(f)).