Low grade mucoepidermoid tumor of Parotid gland presenting as focal asymmetry in the follow-up Radioiodine scan in a patient of differentiated papillary carcinoma of thyroid

Abstract

Low grade mucoepidermoid tumor of the right parotid gland presenting as focal uptake in the follow-up whole body iodine scan in a patient of differentiated papillary carcinoma of thyroid 1 year after successful ablation is presented in this report. Following surgical excision, the histopathology was proven. The illustrated case represents false positive focal accumulation of ¹³¹I in low grade mucoepidermoid carcinoma of the salivary gland that arose early in the follow-up course in differentiated thyroid carcinoma post-radioiodine (RAI). However, the latency period until salivary gland tumor development seemed somewhat short is a factor that doubts the causal relationship with RAI treatment. Salivary gland tumours induced by radiation has been reported primarily in the setting of external radiotherapy. In large volume of cases of thyroid carcinoma treated with radioiodine till date in several centres across the world, such occurrence is rare.