PMC3919912_01
(A) Chest radiography revealied the mediastinal mass on April 23, 2013. (B) Chest computed tomography (CT) revealed a large anterior mediastinal tumor invading the great vessels on April 23, 2013. (C) A percutaneous core cutting needle biopsy of the anterior mediastinal tumor was performed under CT guidance. (D) Chest computed tomography re-examination revealed that the anterior mediastinal tumor was enlarged 1 month after the initial CT scan (May 23, 2013).
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The results of the chest radiograph (Fig. 1A) and enhanced computed tomography (CT) scan (Fig. 1B) revealed a large anterior mediastinal mass, measuring 14.8x12.0x11.5 cm in size and invading the mediastinal great vessels. In addition, a percutaneous core cutting needle biopsy of the anterior mediastinal mass was performed with CT guidance (Fig. 1C). Chest computed tomography re-examination revealed that the anterior mediastinal MTT had enlarged rapidly to 17.0x15.0x12.0 cm on May 23, 2013 (Fig. 1D).
(A) Malignant peripheral nerve sheath tumor (MPNST) cells. Malignant spindle cells with marked pleomorphism and fasciculated architecture were observed (hematoxylin and eosin; magnification, x200). (B) High-powered view of MPNSTs with rhabdomyosarcomatous differentiation. Round cells with eosinophilic cytoplasm were morphologically consistent with rhabdoid differentiation and were identified in a background of classic MPNST (white arrow) (hematoxylin and eosin; magnification, x400). (C) Positive nuclear immunohistochemical staining with S-100 was noted in MPNST (white arrow) (magnification, x400). (D) Positive nuclear immunohistochemical staining with myogenin was noted in rhabdomyoblastic cells (white arrow) (magnification, x400). (E) Positive cytoplasm immunohistochemical staining with desmin was noted in rhabdomyoblastic cells (white arrow) (magnification, x400).
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S-100, and the rhabdomyoblasts were positive for myogenin and desmin, respectively (Fig. 2). Simultaneously, the tumor cells were negative for neuron-specific enolase, B-cell lymphoma 2, cytokeratin 19, cluster of differentiation (CD)57, myogenic regulatory protein, neuronal nuclear antigen and smooth muscle actin.