Case Report: Mucoepidermoid Carcinoma of the Parotid Gland after Radioiodine Therapy for Thyroid Cancer

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 429-448-Thyroid Neoplasia & Case Reports
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-437
Maria Brito*1 and Jessie Block-Galarza2

Background: Mucoepidermoid carcinomas are malignant epithelial neoplasms that usually originate in the salivary glands. Several articles have been published about the risk of multiple secondary primary malignancies associated with radioactive iodine but it is important to note that the radiation dose received by the salivary glands in patients who have already had a thyroidectomy is usually about 10 times greater than that of other organs. Three cases have been described in the literature of mucoepidermoid carcinomas of the salivary glands after radioiodine treatment. Here, we describe the 4th report of a patient developing mucoepidermoid carcinoma of the salivary gland following radioactive iodine treatment for thyroid cancer.

Patient Findings and Summary: A 46 year-old woman who previously underwent total thyroidectomy and ablative treatment with 150 mCi of I131 for papillary thyroid carcinoma presented 8 years later with a 1.0 cm firm palpable mass posterior to the right ear. After initial treatment for PTC, her serum thyroglobulin and thyroglobulin antibodies remained undetectable, thyrogen-stimulated whole body scans and surveillance ultrasounds revealed no evidence of residual thyroid tissue or evidence of metastatic disease. The palpable mass was further evaluated with an MRI, which revealed a 1.2 cm x 1 cm mass in the lateral lobe of the right parotid gland, considered to be most likely a node, but could represent a parotid tumor. The patient proceeded to have surgical excision of this mass and the pathology was reported as a low-grade mucoepidermoid carcinoma of the parotid gland measuring 0.9 cm in its largest dimension.

Conclusion: There is increasing evidence that I131 is not as innocuous as the scientific community previously believed, and that there may be a significant and increasing risk of secondary primary malignancies associated with radioiodine treatment. Although some of these associations have been controversial in the literature, we continue to see a relevant number of cases appearing in the field.

Nothing to Disclose: MB, JB

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