Teaching File: Miliary metastases

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.
References:
1. Primer of diagnostic imaging - Weissleder
2. StatDx.com
Credit: Dr Frank Gaillard
http://www.radpod.org