PMC4822191_01
A 2-year-old girl with left knee pain and a medullary lytic lesion in the proximal tibial metaphysis. (A) Antero-posterior view, (B) Lateral view
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F1
Conventional radiography revealed a 2.5-cm-diameter medullary lytic lesion located centrally in the proximal left tibial metaphysis (Figure 1(Fig. 1)).
Magnetic resonance imaging findings. (A) The T1-weighted image revealed the penumbra sign (white arrow). (B) The fat-suppressed T2-weighted image revealed very high signal intensity of the central part of the lesion. (C) The gadolinium-enhanced fat-suppressed T1-weighted image showed peripheral rim enhancement.
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F2
T1-weighted images (Figure 2A(Fig. 2)), very hyperintense on fat-suppressed T2-weighted images (Figure 2B(Fig. 2)), and not enhanced after gadolinium administration (Figure 2C(Fig. 2)). The rim lining of the cavity was mildly hyperintense on T1-weighted images (Figure 2A(Fig. 2), white arrow), hypointense on fat-suppressed T2-weighted images, and enhanced after gadolinium administration.
Histologic and immunohistological examination. (A) Histologic examination showed multinucleated giant cells and mononuclear histiocytes aggregated with eosinophils and neutrophils (200x). (B) Immunohistologic stains for CD1a confirmed the presence of multinucleated giant cells and mononuclear histiocytes (200x).
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F3
Histologic examination of the specimen showed multinucleated giant cells and mononuclear histiocytes aggregated with eosinophils and neutrophils (Figure 3A(Fig. 3)). Immunohistologic labeling with antibody to CD1a and S100 protein was positive for multinucleated giant cells and mononuclear histiocytes (Figure 3B(Fig. 3)).