Osteoradionecrosis after three-dimensional conformal radiotherapy for recurrent cervical cancer presenting as a progressive osteolytic lesion.

Osteoradionecrosis (ORN) of the pelvic bone presenting as a progressive osteolytic lesion, following three-dimensional conformal radiotherapy (3DCRT) with concurrent chemotherapy, is a clinical diagnostic challenge that must be differentiated from an osseous metastasis. We report on a case with an unusual presentation of ORN mimicking bony metastasis that should be taken note of by physicians. A 46-year-old woman who had recurrent cervical cancer in the right pelvic sidewall underwent concurrent salvage chemoradiotherapy. She received 63 Gy 3DCRT. At 22 months, post-RT, an asymptomatic but enlarging osseous defect in the right ilium, located within the area covered by a 95% isodose line, was demonstrated on pelvic computed tomography (CT). ORN was confirmed by whole-body [18F] fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography (PET) CT scan and CT-guided bone biopsy. A localized, growing ORN of pelvic bone after high-dose 3DCRT is an uncommon late complication. Differential diagnosis between ORN and bony metastasis may be possible with low FDG uptake of ORN on PET-CT scans.