Malignant giant cell tumor in the left upper arm soft tissue of an adolescent: A case report

Figure 1 Posteroanterior shoulder joint radiograph. A linear low-density shadow at the greater tuberosity of the left humerus and small flakes in the upper medullary cavity of the left humerus with slightly reduced density are seen.

Figure 2 Computed tomography of left shoulder joint reveals a soft tissue mass of the left shoulder. A: Strip-like calcifications in the mass; B: The adjacent bone shows an insect-like zone of destruction; C: Small, rounded solid nodules in the lower lobe of the right lung; D: The adjacent bone shows a needle-like periosteal reaction; E: Invasion of the marrow cavity.

Figure 3 Upper arm magnetic resonance imaging. A and B: Mixed moderate hypointensity and hyperintensity on axial (A) and coronal (B) T1-weighted images; C: mixed hyperintensity on coronal fat-saturated T2-weighted images; D: T1-weighted images with contrast demonstrate heterogeneous enhancement of the lesion.

Figure 4 Whole-body ^99mTc-methylene diphosphonate bone scan imaging. Abnormal distribution of radioactive label concentration and increased activity are seen in the left shoulder joint and proximal humerus.

Figure 5 Histopathological images. A: A giant cell tumor with polygonal mononuclear cells and multinucleated osteoclast-like giant cells (hematoxylin and eosin, × 200); B: Immunohistochemical staining revealed strong CD163 positivity (hematoxylin and eosin, × 200); C: Immunohistochemical staining revealed high CD68 positivity (hematoxylin and eosin, × 200).