PMC4802193_01
T2 abdominal and pelvic MRI with contrast on Feburary 13th, 2015 revealed the previously known pelvic tumor (A) along with newly formed hypervascular mesenteric masses (B).
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Abdominal and pelvic magnetic resonance imaging revealed a 7.0 x 6.5 cm pelvic mass along with previously unknown hypervascular mesenteric masses and the patient was worked-up for exploratory laparotomy (Fig. 1).
Microscopically, the pelvic tumor was composed of spindle cells expressing the neurogenic differentiation marker S100 (A). The pelvic tumor did not show any rhabdomyosarcomatous differentiation as indicated by absent Myogenin expression (C) and had a Ki67-proliferative index of 1-3% (E), in line with a low-grad MPNST. Immunohistochemical stainings of the mesenteric nodules showed spindle cells without expression of S100 (B), however, with focally abundant expression of Myogenin (D) and a Ki67-proliferative index of 70-80% (F).
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Immunohistochemically, the spindle-shaped tumor cells homogenously expressed Protein S100 and p53 without evidence of expression of Desmin, Aktin, Caldesmon, Myogenin or CD34 and a Ki67-proliferative index of 1-3% (Fig. 2). Immunohistochemical stainings were negative for Protein S100, GFAP, Neurofibromin, Synaptophysin, Caldesmon, CD34 and CD57 (Fig. 2).