case_images: PMC3350304_01
case_images: Preoperative view showing an enlarging mass in the third web space.
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case_images: fig1
case_images: On examination, there was a firm, round mass measuring 9 x 7 cm in the third web space (Figure 1).
case_images: Preoperative positron emission tomography. (a) Abnormal uptake involving the affected foot. (b) No abnormal uptake was observed except left inguinal region.
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case_images: fig2
case_images: Radiological examination including fluorodeoxyglucose positron emission tomography showed no evidence of definite distant metastases except left inguinal region (Figures 2(a) and 2(b)).
case_images: Intraoperative views of ablative surgery and secondary reconstructive surgery. (a) Ipsilateral inguinal dissection at the first operation. (b) Wide excision of the primary lesion with a 30 mm surgical margin. (c) Free latissimus dorsi musculocutaneous flap transfer to the amputated stump.
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case_images: fig3
case_images: Left inguinal dissection was carried out (Figure 3(a)), and an adequately wide excision of the primary tumor with a 30 mm surgical margin (i.e., transmetatarsal amputation) was performed (Figure 3(b)). One week postoperatively, the stump was resurfaced with a free latissimus dorsi musculocutaneous flap with a split-thickness skin graft following histological confirmation of adequate surgical margins (Figure 3(c)).
case_images: Histological findings. (a) Proliferation of spindle cells with abnormal mitotic activities reminiscent of conventional malignant schwannoma (hematoxylin-eosin, x400). (b), (c) Epithelioid features of round-to-polygonal or rhabdoid cells with cellular atypia resembling malignant melanoma (hematoxylin-eosin, x400). (d) Immunohistochemical staining demonstrating strongly positive for S-100 protein.
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case_images: fig4
case_images: Histologically, the lesion consisted of two components: proliferation of spindle cells with some differentiation to nerve cells, reminiscent of conventional malignant schwannoma (Figure 4(a)), and epithelioid proliferation of round-to-polygonal or rhabdoid cells with hyperchromatic nuclei, reminiscent of malignant melanoma (Figures 4(b) and 4(c)). Tumor cells stained positive for S-100 protein and negative for HMB45 (Figure 4(d)).
case_images: Ten weeks after the first operation. (a), (b) Development of multiple lung metastases (M1, M2, M3).
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case_images: fig5
case_images:  Ten weeks after the first operation, computed tomography demonstrated the development of multiple small bilateral lung nodules (Figures 5(a) and 5(b)).
case_images: After two courses of adjuvant chemotherapy showing good response to all metastases. Note M3 was not recognizable.
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case_images: fig6
case_images: After two courses of the adjuvant therapy, follow-up computed tomography revealed a good response to all abnormal shadows; however, two lesions in segment 8 and one in segment 10 of the left lung field were still observable (Figures 6(a) and 6(b)).
case_images: Twelve months after the first operation. All metastatic lesions were eliminated through the chemotherapy and thoracic surgery.
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case_images: fig7
case_images: At the 12-month followup after radical surgery of the primary tumor, during which time four courses of adjuvant chemotherapy and a thoracic surgery were added, no signs of local recurrence or metastasis were observed (Figures 7(a) and 7(b)).
case_images: Clinical view at 12 month postoperatively.
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case_images: fig8
case_images: The patient maintained ambulation without a brace (Figure 8).