A Case Report and Literature Review of Metastatic Small Cell Carcinoma in Parotid Gland

Small cell lung cancer usually presents as a progressive disease in over 70% of patients. Common organs of metastasis include the liver, adrenal glands, bones, and brain. However, metastasis to the parotid gland is uncommon, as it has been discussed only in case reports. Among all parotid tumors, small cell cancer is rare, seen in only 1.7%.A 60-year-old man presented with a slow-growing, painless tumor of the left parotid gland and peripheral facial paralysis. Neck ultrasound identified a solid mass in the left parotid gland with enlarged lymph nodes in the parotid gland and ipsilateral neck lymphadenopathies with pathologic features in levels 2 and 3. Chest computed tomography (CT) demonstrated subsegmental collapse in the lingula with peribronchial cuffing in this lobe and mild cylindrical bronchiectatic changes in the left lower lobe. CT also showed multiple mediastinal lymphadenopa thies in prevascular, paraaortic, and paratracheal spaces. Core needle biopsy was done, and initial analysis revealed small cell carcinoma in the left parotid gland. Immunohistochemical analysis of the specimen demonstrated and confirmed the diagnosis. The patient was then referred to the radiation oncology unit for treatment. Chemotherapy was initiated with a combination of cisplatin and etoposide. No complications of the chemotherapy were observed after three cycles; treatment and follow-up are ongoing. No irradiation was performed after evaluation by the radiation oncology department. Due to the advanced stage of his disease, treatment is set for palliative purposes only. Small cell lung cancer diagnosed from solitary metastasis to the parotid gland is very rare. Physicians should keep pulmonary origin in mind when faced with a parotid tumor, as without careful examination, the primary focus may be overlooked, negatively impacting survival rates and the prognosis of the patient. Overall, this finding carries a poor prognosis, but the mainstay of treatment is palliation with systemic chemotherapy and possibly irradiation to control symptoms