Discordance of sialography and scintigraphy in unilateral chronic sialadenitis

A Tc-99m pertechnetate salivary gland scintigraphy, digital subtraction sialography (DSS) and cytological findings of a 48-year-old female who received I-131 therapy for the treatment of follicular carcinoma of thyroid are presented. Post radioiodine therapy sialoscintigraphy showed increased blood flow and uptake with decreased secretion in the left parotid gland suggesting acute inflammation. In contrast, DSS and fine needle aspiration biopsy (FNAB) findings were consistent with chronic sialoadenitis. Follow-up scintigraphy one month later showed normal blood flow and decreased uptake and confirmed the diagnosis of chronic sialoadenitis. In right of this case, we conclude that since management of sialoadenitis depends on the stage of inflammation scintigraphic findings should be interpreted together with radiology and FNAB findings if necessary. When chronic sialoadenitis is followed by acute exacerbations, diagnosis based exclusively on sialoscintigraphic findings may result in inadequate patient management.