PMC4533366_01
Sagittal (A) and axial (B) T1-weighted magnetic resonance (MR) images with gadolinium demonstrating an intramedullary tumor with homogeneous enhancement between T4 and T5 level mimicking an ependymoma.
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F1
After gadolinium injection, homogeneous enhancement of the intramedullary lesion was visualized (Fig. 1A, B).
Intraoperative photographs. A: Intraoperative photograph after opening dura showing swollen spinal cord with thick arachnoid membrane. B: Intraoperative photograph after midline myelotomy showing an intramedullary tumor.
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F2
Following dural opening, we found spinal cord swelling with a thick arachnoid membrane and thin pia mater (Fig. 2A). A midline myelotomy was carried out and a grayish tumor immediately appeared (Fig. 2B).
Histological examination of an intramedullary tumor. A: Photomicrograph showing interlacing bundles of fibroblast-like cells with abundant collagen. HE stain, magnification x200. B: Photomicrograph showing high cellularity with spindle-shaped cells. HE stain, magnification x200. C: Immunohistochemical staining for S-100 protein showing that the tumor cells were partially positive; however most of fibrous areas with fibroblast-like cells were negative. Magnification x200. D: Immunohistochemical staining for CD34 showing that most tumor cells were diffusely positive. Magnification x200. E: Neurofilament staining showing a few axons in the tumor tissues. Magnification x200. F: Epithelial membrane antigen (EMA) staining showing that most tumor cells were negative except limited numbers of EMA positive cells. Magnification x200.
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F3
Microscopically, in some parts of the tumor, tumor cells were composed of interlacing bundles of fibroblast-like cells with abundant collagen (Fig. 3A). In other parts of the tumor, the tumor was characterized by high cellularity with spindle-shaped cells (Fig. 3B). Immunohistochemical staining for S-100 protein showed that the tumor cells were partially positive; however, most of fibrous areas with fibroblast-like cells were negative (Fig. 3C). Immunohistochemical staining for CD34 showed that most of the tumor cells were diffusely positive and, especially, fibrous areas with fibroblast-like cells were strongly positive (Fig. 3D). Neurofilament staining showed a few axons in the tumor tissues (Fig. 3E). Most tumor cells were negative for epithelial membrane antigen (EMA) except only limited numbers of EMA-positive cells that was considered to be residual perineurium (Fig. 3F).