This patient had had a thyroid malignancy treated with surgical excision and radioactive iodine. This scan was obtained as followup. Note the innumerable miliary metastases scattered throughout both lungs. Thyroid cancer is a classical cause of miliary metastases, with other common primaries being pancreatic cancer, breast cancer and melanoma.

Differential diagnosis includes sarcoidosis, miliary TB and silicosis.

1. Primer of diagnostic imaging – Weissleder

Credit: Dr Frank Gaillard