Isolated Thyroid Metastasis of Small Cell Lung Cancer: A Case Report

Abstract

Metastasis of non-thyroidal malignancies to the thyroid glands is rare and has only been reported in around 1.4%–3% of all surgeries for thyroid malignancy. Among the 4 subtypes of lung cancer, small cell lung carcinoma is the rarest. We report an unusual presentation of small cell lung cancer (SCLC) metastasis to the thyroid in a patient. A 70-year-old female with chronic hepatitis B infection presented with chronic cough lasting 4 months, weight loss, and left scapula pain. SCLC (clinical stage IVA, T4N3M1a) with pleural seeding was diagnosed by bronchial biopsy. The patient underwent palliative chemotherapy consisting of etoposide and cisplatin for 6 months followed by palliative radiation therapy for 2 months and achieved local control of the lung lesion. However, thyroid masses suggesting metastasis from the lung developed during follow-up. The patient underwent total thyroidectomy with bilateral central neck node dissection. Pathologic examination revealed metastatic small cell carcinomas in both thyroid glands with central neck node metastasis. The postoperative course was uneventful without complications. The patient was discharged on postoperative day 2. Until now, she visits the outpatient clinic for regular follow-up. The metastatic pattern presented in this report is very rare. A multidisciplinary approach is necessary to determine if the patient is likely to benefit from thyroidectomy, and to provide optimal clinical management for improved outcomes.