PMC9938535_01
Imaging of the parotid gland. (a) CT scan before surgery, the red arrow shows a left parotid occupancy (on April 11, 2021). (b) Nuclear magnetic resonance (MRI) scan after surgery and before chemotherapy and radiotherapy (RT) (on May 15, 2021). (c) MRI scan after chemotherapy and RT (on November 11, 2021). (d) MRI scan recently (on December 5, 2022).
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April 11, 2021 suggested a tumor in the left parotid gland, with a size of approximately 3.0 cm x 2.2 cm (Figure 1a). According to the preoperative images, the clinical diagnosis of a benign tumor was considered. We did not find residual tumor in postoperative MRI (Figure 1b), what else, F-18 FDG PET/CT showed no abnormal tumor metabolic uptake. The MRI right after radiotherapy did not find a tumor (Figure 1c). Up to now, no tumor recurrence or metastasis was found (Figure 1d).
Histopathology of the parotid tumor. (a) The spindle-cell neoplastic cells present variable amounts of melanin (hematoxylin-eosin stain, original magnification, x40). (b-d) Immunohistochemical staining of the tumor shows strong immunoreactivity in HMB-45, S-100, and SOX10, respectively (immunohistochemical stain, original magnification, x100).
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In addition, no EWSR1 gene translocation was found, all supported a malignant melanoma of the left inferior parotid gland (Figure 2), but as the patient refused to accept the gene detection, we could not obtain the gene state of BRAF or MEK.