Figure Legends
Figure 1: Initial imaging, (A) axial chest CT, (B) coronal chest CT, (C) F-18 FDG PET/CT, (D) ultrasound showing mass from lower neck to posterior upper mediastinum
Figure 2: (A) The lesion was fatty tissue-like yellowsish mass on gross examination. (B) Polygonal cells resembling brown fat with multivacuolated cytoplasm were admixed with mature adipocytes in the background of myxoid stroma. (C) Small, delicate, branching capillaries were noted. (D) No significant nuclear atypism was seen. (E) CD31 immunostaining highlighted hibernoma cells and capillary endothelial cells. (F) The recurred tumor at supraclavicular area had similar histologic features with more pronounced myxoid stroma.
Figure 3: neck CT showing recurred tumor at left supraclavicular area (red arrow), (A) axial view, (B) coronal view
Figure 4: Intraoperational photo of left supraclavicular recurred hibernoma, (A) hibernoma was well circumscribed with capsule, and delicate dissection was performed to save nearby structures, (B) anterior plane of removed hibernoma, (C) posterior plane of removed hibernoma