case_images: PMC7133003_01
case_images: X-ray of the forearm showing a soft tissue tumor with areas of calcification (arrows)
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case_images: PMC7133003_01_13569_2020_129_Fig1_HTML.jpg
case_images: Fig1
case_images: An X-ray of the forearm showed a soft tissue mass with irregular calcifications (Fig. 1) and CT scan of the limb confirmed this finding.
case_images: Magnetic Resonance Imaging (MRI) showing a soft tissue mass in the subcutis. The lesion is isointense to muscle in T1-weighted sequence (a), hyperintense on T2-weighted sequence (b), and shows contrast medium enhancement on T1-weighted sequence (c)
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case_images: Fig2
case_images: The mass was isointense to muscle in T1-weighted sequence (Fig. 2a), hyperintense on T2-weighted sequence (Fig. 2b), with contrast medium enhancement on T1-weighted sequence (Fig. 2c) and highly vascular (Fig. 3).
case_images: Low power view showing the two abruptly separated components of the tumor. Well-differentiated leiomyosarcoma is shown in the lower and high-grade osteosarcoma in the upper right (40x)
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case_images: Fig4
case_images: Histologically, the tumor showed two different, abruptly separated components (Fig. 4).
case_images: Well-differentiated leiomyosarcoma consisting of spindle cells arranged in intersecting fascicles (200x)
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case_images: Fig5
case_images: One consisted of a proliferation of atypical spindle or ovoid cells with cigar-shaped nuclei and eosinophilic cytoplasm arranged in long interlacing fascicles, an appearance consistent with leiomyosarcoma (Fig. 5).
case_images: High-grade osteosarcoma consisting of highly atypical cells with osteoid matrix production (a; 200x). In other areas neoplastic cells produced cartilage matrix (b; 100x)
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case_images: Fig6
case_images: The other component consisted of atypical pleomorphic cells producing osteoid matrix in disorganized trabeculae with focal calcification (Fig. 6).
case_images: The leiomyosarcoma component (on the right in a and b) is positive for alpha smooth muscle actin (a, 40x; inset 400x) and desmin (b, 100x), whereas the osteosarcoma component (on the left in a and b) is negative. SATB2 was positive in the nuclei of neoplastic cells in the osteosarcoma component (c, 400x) and negative in the leiomyosarcoma (d, 400x)
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case_images: Fig7
case_images: Immunohistochemically, areas with leiomyosarcomatous appearance were strongly positive for alpha smooth muscle actin (Fig. 7a) and desmin (Fig. 7b), whereas the osteosarcomatous component was negative. S100 protein, CD34 and CD31. SATB2, a marker of osteoblastic differentiation was positive only in the osteosarcomatous component, whereas leiomyosarcoma areas were negative (Fig. 7c, d).