PMC10176195_01
Pelvic and lumbosacral spine XRs at current presentation to the emergency department (a) and 7 years prior for an unrelated complaint (b), showing new bony destruction of the right aspect of the sacrum (indicated by asterisk).
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F1
Pelvic X-rays performed in the Emergency Department noted bony destruction of the sacrum, which was not present on prior spine X-rays performed several years ago for an unrelated hospital visit (shown in Fig. 1).
Representative cross-sectional images of the sacrococcygeal chordoma. Axial and sagittal CT (a, b); axial T1 (c) and T2 FS (d) MRI, showing significant tumour extension through the right sciatic notch and anterior displacement of the right sciatic nerve; and sagittal T2 TIRM (e) images demonstrating mass effect of the tumour on the adjacent rectum, without rectal wall invasion/involvement.
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F2
Subsequent cross-sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) (shown in Fig. 2a-e) confirmed a large sacrococcygeal mass measuring 8.7 x 14.3 x 9.6 cm, with destruction of the S3, S4, and S5 vertebral bodies and the first coccygeal segment (Co1) and tumour extension via the right sciatic notch into the right gluteal region, with no evidence of metastases nor nodal spread beyond the primary sacral tumour.
Dose distribution and dose-volume histogram (DVH) of final VMAT-SBRT plan. Axial view (a) showing colourwash of 95% (33.25 Gy) isodose coverage, sagittal view (b) showing sparing of the rectum with safety margin of 5 mm (rectum_PRV), and DVH (c). VMAT, volumetric modulated arc therapy.
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F3
The dose distribution and dose-volume histogram are shown in Figure 3a-c.
Radiologic response of sacrococcygeal tumour 9 months post-SBRT. MRI at 9 months post-SBRT (a) versus baseline (b) showing decrease in tumour size from 12.6 to 6.6 cm, with decreased extension through the right sciatic notch and relieved mass effect on the right sciatic nerve. Sagittal views at 9 months post-SBRT (c) versus baseline (d) showing significant regression of tumour inferoposteriorly with relief of mass effect on adjacent rectum.
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F4
Timeline of interventions and outcomes. The timeline from admission detailing the diagnostic and therapeutic interventions performed, with respect to the patient's reported pain score and opioid requirements.
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F5
With regards to pain control, the patient's opioid analgesic requirement reduced gradually over time, and he was eventually weaned off completely approximately 21 months after RT (shown in Fig. 5).