Incidental Detection of Sacral Insufficiency Fracture on 68Ga-FAPI PET/MR

A 61-year-old woman with low-set rectal adenocarcinoma (cT4bN1Mx) received radiotherapy and chemotherapy for 4 months, and then she underwent F-18-FDG PET/CT and Ga-68-FAPI PET/MR. Obviously increased Ga-68-FAPI uptake was unexpectedly revealed on both sides of the sacrum with low F-18-FDG uptake, which was diagnosed as insufficiency fracture based on the imaging features, advanced patient age, and radiotherapy history. The possibility of insufficiency fracture should be considered when accidental, symmetrically increased sacral Ga-68-FAPI uptake appears in cancer patients, and differential diagnosis should be carefully made.

Automated summary

In cancer patients, the possibility of insufficiency fracture should be considered when accidentally symmetrically increased sacral Ga-68-FAPI uptake appears. Careful differential diagnosis should be made in such cases.