Background: Radioiodine therapy has long been used in the treatment of hyperthyroid patients. Salivary complications secondary to radioactive iodine (RAI) treatment are well documented, there is little in the literature addressing salivary gland duct obstruction. We present a rare case of salivary gland duct obstruction developed 2 months after RAI treatment. Case Presentation: We describe a 50-year-old male, treated with RAI for hyperthyroidism. He developed pain and swelling in the left submandibular region, 2 months after receiving RAI treatment (25 mCi). His salivary gland scintigraphy was done after injecting 370 MBq (15 mCi) of Tc99m pertechnetate in supine position. It revealed retention of radiotracer in the left submandibular gland with no drainage through the duct system, even on giving lemon stimulus, favoring submandibular gland duct obstruction. Conclusion: We report this rare complication of submandibular gland duct injury occurring after RAI therapy. The occurrence of this complication even after low dose of radioiodine administration may be listed in gamut. All necessary measures must be taken to reduce such potential complications.

Keywords: Radioactive iodine treatment, Submandibular gland, salivary gland scintigraphy, case report