PMC5514167_01
Initial presentation. T1-weighted enhanced magnetic resonance imaging head scans. (A and B) Preoperative. (C) Postoperative. The green arrows indicate preoperative gross tumor and the red arrow indicates postoperative gross residual disease.
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A magnetic resonance imagining (MRI) head scan revealed an extra-axial mass with an extension into the posterior left orbit and suspected involvement of the left cavernous sinus, superior orbital fissure, and optic nerve (Fig 1A,B). A postoperative MRI scan revealed subtotal resection (Simpson grade 4) with residual tumor adjacent to the left cavernous sinus, measuring 4 mm by 10 mm (transverse by craniocaudal; Fig 1C).
First recurrence after surgical resection. T1-weighted magnetic resonance imaging head scans post-gadolinium. (A) Coronal view. (B) Axial view. Green arrow indicates gross recurrent tumor.
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The patient was asymptomatic with stable imaging until the fourth-year surveillance MRI scan, which revealed growth of the residual tumor to 12 mm by 18 mm (Fig 2).
Recurrence after first course of radiation therapy. Coronal T1 weighted magnetic resonance imaging post gadolinium. Green arrows indicate gross recurrent disease both outside (A) and within (B) the original radiation treatment field.
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The next regularly scheduled surveillance MRI scan 3 months later revealed tumor enlargement with extensions along the floor of the middle cranial fossa and through the foramen ovale and foramen rotundum into the infratemporal fossa (Fig 3).
Recurrent disease after salvage radiation therapy superimposed over the original treatment plan, demonstrating recurrence outside of the original target volumes. Non-contrast computed tomography images. (A-C) Axial, sagittal, and coronal views, respectively. Green is clinical tumor volume from time of first radiation; magenta is clinical tumor volume per Radiation Therapy Oncology Group 0539 recommendations; blue is gross tumor volume for recurrent disease after first radiation; and red is 95% isodose line from the first course of radiation treatment.
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The MRI scan that demonstrated recurrence was fused with the previous treatment plan, which revealed that the GTV was flush against the inner table of the skull base with the regrowth of tumor occurring both within and outside of the previous high-dose volumes (Fig 4).
Non-contrast computed tomography images. Blue is gross tumor volume for the recurrent tumor. (A-C) Retreatment plan for recurrence with the 95% isodose line in red. (D-F) Composite plan that sums the doses for the initial and retreatment plans with the 51 Gy (red) and 90 Gy (green) isodose lines indicated.
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Because of the patient's progressive symptoms, repeat image guided IMRT to a dose of 54 Gy in 1.8 Gy/fraction was offered (Fig 5).
Post-reirradiation. T1-weighted magnetic resonance imaging head scans post-gadolinium. (A) 8-week follow-up; (B) 6-month follow-up. Green arrow indicates new enhancement, possibly due to a radiation-related injury.
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At the initial 8-week follow-up visit, improvement was noted in the patient's left-sided facial numbness and pain and a significant reduction in tumor size was found on MRI scan (Fig 6A). Repeat imaging scans, however, demonstrated ongoing stability of the tumor with new enhancements in the medial temporal lobe consistent with radiation injury (Fig 6B).