Diffusely Increased Bone Marrow Uptake on DOTATATE PET/CT Due to PRRT-related Myelodysplasia Syndrome

We report an unusual imaging finding on DOTATATE PET/CT in a patient with prior 177Lu-DOTATATE treatment for metastatic small bowel neuroendocrine tumor. Five years post-treatment follow-up DOTATATE PET/CT for fatigue and back pain showed new diffusely increased bone marrow uptake in addition to focal uptake corresponding to known metastases. Faint/mild bone marrow uptake of DOTATATE can be seen due to the presence of SST-2 receptor on CD-34 hematopoietic progenitor cells in the marrow, but diffusely increased marrow uptake, as in this case, was not deemed physiologic and was concerning for marrow pathology. Subsequent bone marrow biopsy confirmed therapy-related myelodysplastic syndrome (t-MDS).