In October 2018, a 64-year-old man presented at the Department of Otolaryngology, Head and Neck Surgery, First Hospital of Jilin University, Changchun, Jilin Province, China with a painless mass below the right ear and complained of peripheral facial paralysis for a month. A physical examination found a 2.0 × 2.0 cm mass, with poor mobility, in the right parotid region. The accompanied peripheral facial paralysis on the right side was classified as House-Brackmann Grade III. Neck ultrasound identified a solid mass in the right parotid gland with enlargement of the lymph nodes in the gland and the right submandibular lymph nodes. Lung computed tomography (CT; ) demonstrated abnormalities in the upper and middle lobes of the right lung and intermediate bronchus, with obstructive pneumonia, as well as enlargement of the right hilar and mediastinal lymph nodes. The patient showed no symptoms of coughing, expectoration or haemoptysis.\nThe patient insisted on confirming the malignancy of the solid mass in the right parotid gland but refused to undergo preoperative needle biopsy. Intraoperative pathology confirmed a malignant tumour with metastatic potential. Thus, the right parotid gland and facial nerve were resected and selective neck dissection performed. Postoperative histopathological analysis demonstrated small cell carcinoma in the right parotid gland () with involvement of the right neck lymph nodes (one of eight). Bronchoscopy was performed and the pathological results were small cell carcinoma (. Immunohistochemical analysis of the postoperative pathological specimen indicated positive staining for pan-cytokeratin, CD56, chromaffin granule protein A, synapsin (Syn) and thyroid transcription factor-1 (TTF-1) (), partial positive staining of Ki-67 and cytokeratin 7, and negative staining for CD99, cytokeratin 5/6 and common leukocyte antigen (LCA). Immunohistochemical analysis of the bronchoscopy pathological specimen demonstrated positivity of pan-cytokeratin, CD56, Syn, TTF-1, partial positivity of Ki-67, but no staining of P40, cytokeratin 20, cytokeratin 5/6, vimentin and LCA, suggesting possible metastasis of small cell lung cancer to the parotid gland. Positron emission tomography (PET)/CT identified a hypermetabolic lesion in the right upper and middle lobes of lung and intermediate bronchus (), suggesting possible central lung cancer with distal obstruction and inflammation. Multiple lymph nodes were involved, and localized peritoneal thickening with hypermetabolism was observed under the right lobe of the liver, suggesting possible liver metastasis. Although hyperplasia, calcification and a hypermetabolic area were observed in the prostate under PET/CT, analysis of prostate-specific antigen in the serum and magnetic resonance imaging (MRI) showed no lesion.\nThe patient recovered well after the surgery and was scored 1 on the Eastern Cooperative Oncology Group performance scale. From postoperative day 15, the patient started to undergo six cycles of adjuvant chemotherapy with a combination of cisplatin + etoposide: days 1–3, 75 mg/m2 cisplatin intravenously + 100 mg/m2 etoposide intravenously; day 4, 100 mg/m2 etoposide intravenously; day 5, 50 mg/m2 etoposide intravenously; and the cycle was repeated every 20 days. Supportive therapy was also provided. No complications of the chemotherapy were observed after three cycles, treatment and follow-up are ongoing. Ethical approval was not required for this case report. The patient provided written informed consent for the publication of their data.
A 79-year-old female patient with a history of appendectomy and cholecystectomy was diagnosed with hypertension and diabetes mellitus. She was referred to an outpatient clinic with a complaint of a 3 × 4 cm mass that had been located in the right parotid region for eight months and recently grew rapidly to cause total facial nerve palsy. The mass was mobile, and the patient did not report pain. The patient's computed tomography (CT) indicated a lobular-contoured, 4 × 2.5 cm solid mass lesion with heterogeneous contrast enhancement in the anterior lobe of the right parotid gland (). A fine needle aspiration biopsy revealed a malignancy of an unknown type. Neither physical and endoscopic examinations nor positron emission tomography-computed tomography (PET-CT) checks succeeded in establishing the primary origin of the malignancy.\nHowever, an elevated skin flap revealed a pigmented lesion that had infiltrated the superficial parotid gland. Following a frozen-section examination, the patient was diagnosed with melanoma. We observed the temporozygomatic and buccal branches of the facial nerve penetrating a 5 × 6 cm mass originating from the superficial lobe of the parotid gland (). We then performed a total parotidectomy operation in which we resected the temporozygomatic and buccal branches and dissected the deep lobe. The results of an immunohistochemical analysis found the melanoma to be HMB-45 positive, S100 positive, Melan-A positive, and PanCK negative. These findings verified the malignant melanoma diagnosis (Figures , , , and ).\nNo primary origin of the melanoma was detected in the head, the neck, or any other region during the patient's postoperative dermatology consultation. Considering the possibility that the primary metastatic malignant melanoma might have regressed, we decided to check the patient's earlier photographs. Upon examination of photographs that were taken five to six years ago, we detected a 3 × 3 cm hyperpigmented lesion in the right facial region (Figures and ). The patient reported that the lesion gradually disappeared spontaneously. We considered the possibility that the metastatic malignant melanoma's primary tumor was likely to have regressed at a later time.