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Acute-Onset Neck Swelling Following PET/CT
This case features a patient presenting with acute-onset neck swelling following PET/CT, ultimately diagnosed with contrast-induced acute sialadenitis, also known as iodine mumps.
Imaging overview:
Axial contrast-enhanced PET/CT demonstrates normal submandibular glands prior to contrast administration. Axial and sagittal contrast-enhanced CT obtained one day later shows interval development of bilaterally enlarged, edematous, and avidly enhancing submandibular glands with indistinct margins and infiltration of the surrounding fat, confirming the new onset of sialadenitis in direct temporal relation to iodinated contrast administration.
Clinical insight:
Contrast-induced acute sialadenitis, colloquially termed iodine mumps, is a rare adverse reaction to iodinated contrast media characterized by painless acute swelling of the salivary glands. The submandibular glands are most commonly affected. Key imaging features include bilateral glandular enlargement with avid enhancement and perilandular fat infiltration, with findings absent on any prior imaging. The underlying pathophysiology is poorly understood and any association with renal insufficiency remains unclear. Symptoms are typically self-limiting and resolve within 24 hours with supportive care. Recognizing this entity is important to avoid unnecessary workup for other causes of acute neck swelling in the post-contrast setting.
Case courtesy of Adam Doedtman, MD, and Brian Graner, MD, Indiana University School of Medicine.