Contrast-induced sialadenitis associated with neuroendovascular aneurysm embolization: Two illustrative cases

Background: Contrast-induced sialadenitis is a rare inflammatory response to iodinated contrast that may present as acute parotid or submandibular swelling. Its mechanism remains poorly defined, making prompt recognition after neuroendovascular procedures essential. Case Description: Two patients developed acute neck swelling after elective endovascular treatment of unruptured intracranial aneurysms with iopamidol. The first underwent flow-diverter placement for a right paraclinoid internal carotid artery aneurysm using 140 mL of contrast and developed right cervical swelling within hours. Computed tomography angiography showed bilateral periparotid and submandibular soft-tissue swelling and stranding, without extravasation or vascular complication. Symptoms resolved with local heat application. The second underwent stent-assisted coil embolization of a left internal carotid artery terminus aneurysm using 175 mL of contrast and developed right-sided neck swelling approximately 12 h later. Contrast-enhanced computed tomography showed acute right submandibular sialadenitis without abscess or vascular abnormality. Warm compress, gentle massage, and sialogogues led to complete resolution by postoperative day 8. Conclusion: Contrast-induced sialadenitis should be considered in acute salivary gland swelling after iodinated contrast exposure during neuroendovascular procedures, including in patients with normal renal function. Imaging helps exclude urgent mimics such as vascular injury, abscess, or edema. After dangerous etiologies are ruled out, conservative treatment is typically effective.