Buttock pain in a 78-year-old woman
History
78-year-old woman with 5 weeks of low back and buttock pain, worse on standing, after no trauma. Endometrial cancer treated with hysterectomy and pelvic external-beam radiotherapy 2 years ago; osteoporosis on DXA, not on treatment. Pelvic radiographs are unremarkable. Request: 'Bone metastases?'
Step 1 · Whole-body bone scan
The delayed images show vertical bands of uptake in both sacral alae joined by a horizontal band across the sacral body, with a focus at the left parasymphyseal pubis and a horizontal band at the L1 endplate. What is the sacral pattern, and what does it suggest?