Recurrent giant cell tumor of foot detected by F18-FDG PET/CT
A 48-year-old female patient diagnosed to have GCT of right foot was subjected to excision, curettage and arthrodesis of ankle joint. Six months post-surgery she presented with increasing pain in right foot and recurrence was suspected. MRI could not be carried out due to surgical implant in situ. Total body F-18 FDG PET/CT acquired 60 min after intravenous injection of 10.2 mCi of F18-FDG was performed for detection of recurrence. Diagnostic quality CT images were acquired as part of the study. It showed intense uptake of FDG in soft-tissues in right hind foot along the anterior and medial surface of the right ankle joint. FDG uptake was also seen to involve the inferior surface of talus, cuboid, lateral and intermediate cuneiform, navicular, talus and calcaneum bones of the foot []. However, exact soft-tissue delineation was not possible due to surgical implant in situ leading to artefacts on CT. Later patient underwent biopsy from the suspected area, which confirmed recurrence. Patient was subsequently subjected to below knee amputation due to involvement of talar bone. Histopathologically the amputated specimen showed giant cell tumor of intermediate grade with involvement of inferior surface of talus, cuboid, lateral and intermediate cuneiform bones, navicular, and calcaneum correlating exactly with the F18-FDG PET/CT findings.