case_images: PMC7758561_01
case_images: [18F]FDG-PET/CT scan series of a patient with very severe aplastic anemia and
  mediastinal tumor. The patient was referred for evaluation of a mediastinal mass that
  showed a moderate [18F]FDG uptake (SUVmax: 5.1), suspicious for thymoma (b: fused axial
  PET/CT slice with red arrow pointing at the mass). In addition, multiple, highly
  metabolic bone lesions were detected, predominantly affecting the ribs, as demonstrated
  on MIP-maximum intensity projection (a) and fused axial slice (c, green arrows). After
  withdrawal of the ongoing G-CSF therapy a second [18F]FDG-PET/CT was performed 10 days
  after the first scan, showing an unaltered moderate tracer accumulation in the
  mediastinal mass with an SUVmax of 4.6 (e: red arrow). However, the initially highly
  FDG-avid bone lesions almost completely resolved, with only a faint uptake left in some
  residual lesions (d: maximum intensity projection and f: fused axial slice; green arrow
  pointing at residual focal uptake in the scapula with an SUVmax decreasing from 14.7 on
  the first scan to 2.6). The findings are highly suggestive of a G-CSF-induced [18F]FDG
  accumulation in the functionally active hematopoietic bone marrow.
case_images: 10.1177_2040620720977613-fig1.jpg
case_images: PMC7758561_01_10.1177_2040620720977613-fig1.jpg
case_images: fig1-2040620720977613
case_images: Interestingly, besides a moderately hypermetabolic mediastinal lesion, disseminated focal skeletal tracer uptake of high intensity was observed (Figure 1) on [18F]FDG-PET/CT, which was primarily interpreted as highly suspicious of skeletal metastases.