pulmonary small cell carcinoma with thyroid and cerebellum metastases

Pulmonary small cell carcinoma typically metastasizes to lymph nodes, liver, adrenal glands, brain, and pleura; thyroid involvement is exceptionally rare. a 57-yearold woman presented with an eight-month history of progressive dyspnea. clinical examination revealed an enlarged thyroid gland with palpable nodules in both lobes. contrast-enhanced chest ct demonstrated a lobulated right hilar mass extending into the posterior mediastinum. ct-guided biopsy of the hilar lesion confirmed small cell lung carcinoma on histopathology. fine needle aspiration of the thyroid nodules yielded hypercellular smears containing medium-sized round cells with hyperchromatic nuclei. to exclude primary medullary thyroid carcinoma with pulmonary metastasis,serum calcitonin and carcinoembryonic antigen (cea) were measured, revealing levels of 20 pg/ml and 49.91 ng/ml, respectively. integrating these findings, the diagnosis of pulmonary small cell carcinoma with thyroid metastasis was established. this case underscores that, although rare, the thyroid gland can serve as a metastatic site for small cell lung carcinoma. therefore, in patients with a known primary malignancy,the appearance of a new thyroid nodule warrants prompt evaluation for possible metastatic disease.