Patients with intrathyroidal metastasis may present with previous history of malignancy or they may present with a secondary neoplasm prompting us to search for the primary site. A 32-year-old male presented with a 4-month history of thyroid swelling and abdomen pain. Fine-needle aspiration cytology from the thyroid swelling revealed deposits from the mucinous adenocarcinoma. The further diagnostic and metastatic work-up identified a diffuse carcinoma of the stomach as the primary site with liver as secondary and retroperitoneal lymph nodes having mucinous deposits with associated Peutz-Jeghers polyposis. This is the first report in the English literature of intrathyroidal metastasis from carcinoma of the stomach with Peutz-Jeghers polyposis presenting primarily as a thyroid swelling. Preoperative diagnosis, proper evaluation and high degree of suspicion may avoid unnecessary thyroidectomy and effective palliation can be achieved with chemotherapy in view of disseminated disease.