PMC10105323_01
a Patient's appearance at the initial visit with marked left buccal swelling. b After the first course of QUAD SHOT and chemotherapy (day 41 after hospitalization, just before the second QUAD SHOT). Tumor necrosis with skin defects was noticeable. c After parotidectomy, followed by reconstruction with femoral skin valve.
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F1
She was hospitalized due to deterioration of her general condition, caused by local inflammation and severe hypercalcemia (Fig. 1a). Since the adhesion of the primary tumor was reduced and a safe margin of resection and reconstruction could be achieved (Fig. 1b), the patient's treatment plan was promptly changed to resection of the primary lesion. Parotidectomy and reconstruction with a femoral skin valve were completed on day 73 (Fig. 1c).
Upper row: axial CT images of the primary tumor in chronological order. a Pre-treatment; bulky mass including internal necrosis (asterisk) and swollen lymph node (arrow). b After the second course of QUAD SHOT (day 55 after hospitalization), the lymph node metastasis vanished. c Post-parotidectomy. Lower row: axial CT images of lung metastasis. d-f correspond to (a-c), respectively. Tumor volume decreased over time, and the surrounding pneumonia disappeared. CT, computed tomography.
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F2
Computed tomography showed a large primary tumor in the left parotid gland with a maximum diameter of 10 cm, lymph node metastases in the ipsilateral neck, and metastasis in the lower lobe of the right lung (Fig. 2a, d). Although resection of the bulky primary lesion was initially envisaged, it was deemed that there was no surgical indication for the following reasons: (i) it was not radical due to the presence of pulmonary metastasis; (ii) the tumor appeared to have invaded the masseter muscle (Fig. 2a), requiring a lengthy reconstructive surgery; and (iii) systemic inflammation caused by infection of the necrotic lesion, worsening of liver function, and low nutritional status (Table 1) made prolonged anesthesia extremely difficult. Evaluation computed tomography at the end of two courses showed the disappearance of the lymph node swelling and volume reduction of the lung metastasis (Fig. 2b, e). The patient has since continued a fifth course of FP-pembrolizumab chemotherapy, which has further reduced the lung metastasis (Fig. 2c, f).
Irradiated field and dose distribution of the first QUAD SHOT. a CTV, clinical target volume (yellow); PTV, planning target volume (cyan). b Target tumor was enclosed in the 95% area relative to the prescribed dose of 3.5 Gy.
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F3
Due to poor bleeding control at the biopsy puncture site and the need for early treatment with hemostasis, the first QUAD SHOT of 14 Gy in four fractions twice daily was administered with palliative intent on days 17 and 18 after admission (Fig. 3).