PMC4898217_01
Female child with Sotos syndrome and soft-tissue sarcoma. Axial MR images obtained at initial presentation show an ill-defined mass (arrows) in the vastus lateralis muscle. Axial T1-weighted MR image (a) shows the mass to be predominantly isointense to muscle with peripheral areas of high signal, potentially due to fat or hemorrhage. Axial STIR MR image (b) shows the mass to have heterogeneously high signal. Axial T1-weighted, fat-suppressed MR image post IV gadolinium (c) shows the mass to have intense heterogeneous enhancement.
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The patient underwent an MRI during initial evaluation that showed an ill-defined, intensely enhancing mass in the vastus lateralis muscle (Figure 2, Figure 3).
Female child with Sotos syndrome and soft-tissue sarcoma. Sagittal MR images obtained at initial presentation show an ill-defined soft tissue mass (arrows). Sagittal T1-weighted MR image (a) shows the mass to be predominantly isointense to muscle with peripheral areas of high signal (white arrowheads). Sagittal STIR MR image (b) shows the mass to be heterogeneously high in signal with a rounded low signal focus (black arrowhead). Sagittal T1-weighted, fat-suppressed MR image post IV gadolinium (c) again demonstrates heterogeneous enhancement.
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The patient underwent an MRI during initial evaluation that showed an ill-defined, intensely enhancing mass in the vastus lateralis muscle (Figure 2, Figure 3).
Female child with Sotos syndrome and soft-tissue sarcoma. Hematoxylin- and eosin-stained section of tissue from the initial surgical excision at low magnification shows a high-grade spindle-cell sarcoma with nuclear pleomorphism.
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Histological evaluation revealed high-grade spindle-cell sarcoma (Figure 4A, Figure 4B, Figure 4C).
Female child with Sotos syndrome and soft-tissue sarcoma. Hematoxylin- and eosin-stained section of tissue from the initial surgical excision at high magnification shows a high-grade spindle-cell sarcoma with nuclear pleomorphism.
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Radiographs at the time of orthopaedic evaluation showed a large, nonspecific soft-tissue mass in the distal thigh with a small area of calcification (Fig. 5).
Female child with Sotos syndrome and soft-tissue sarcoma. Immunostain for smooth muscle actin is positive, indicating myofibroblastic differentiation.
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MR imaging demonstrated a heterogeneous, hemorrhagic seroma in the surgical bed with irregular peripheral enhancement suggesting residual tumor (Fig. 6).
Female child with Sotos syndrome and soft-tissue sarcoma. AP (a) and lateral (b) radiographs of the knee obtained after the initial, incomplete excision demonstrate a nonspecific soft-tissue mass (arrow) in the distal thigh with a small area of calcification or periosteal reaction (arrowhead).
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The MRI also showed fluid in the surgical site to be contiguous with the suprapatellar bursa and knee-joint space (Fig. 7).
Female child with Sotos syndrome and soft-tissue sarcoma. Axial MR images obtained after the initial excision show a complex, predominantly fluid signal mass (arrows) in the operative bed. Axial T1-weighted MR image (a) shows the mass to be hypointense to muscle with peripheral, mildly increased signal. Axial STIR MR image (b) shows hyperintense fluid centrally with irregular, peripheral, intermediate signal intensity. Axial T1-weighted, fat-suppressed MR image post IV gadolinium (c) shows irregular peripheral enhancement suggesting that residual tumor may be present.
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Additional imaging performed for staging demonstrated ipsilateral enlarged iliac and inguinal lymph nodes (Fig. 8) and an indeterminant 4-mm pulmonary nodule (Fig. 9).
Female child with Sotos syndrome and soft-tissue sarcoma. Coronal T2-weighted, fat-suppressed MR image through the low pelvis shows enlarged left internal iliac and inguinal lymph nodes (arrows).
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The patient subsequently underwent the amputation for definitive treatment (Fig. 10).
Female child with Sotos syndrome and soft-tissue sarcoma. Axial unenhanced CT of the lungs shows an indeterminant 4-mm nodule (arrow) in the left lower lobe. This study is degraded by patient motion.
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Histologic examination revealed a small area of residual tumor in a background of cystic necrosis (Figure 11A, Figure 11B).