Toxoplasmosis lymphadenitis of parotid gland concurrent with papillary thyroid carcinoma: A dilemma in differential diagnosis

We report a case of toxoplasmosis lymphadenitis simulating a parotid mass concurrent with a papillary thyroid carcinoma. A 55-year-old male presented symptomless masses in the left lower neck and right preauricular region for 2 months. Physical examination revealed a 2 cm × 2-cm firm mass in the right parotid region and a 3-cm diameter soft mass in the left lobe of thyroid gland. Computed tomography confirmed a lobulated nodule, embedded in the right parotid gland, and; a left thyroid nodule, which resembled a papillary thyroid carcinoma. Fine-needle aspiration (FNA) of the left thyroid lobe suggested a papillary thyroid carcinoma. A radical thyroidectomy, central neck lymph node dissection, and right superficial parotidectomy were performed. Histopathological examination of the surgical specimen supported the diagnosis of a papillary carcinoma of the left thyroid lobe and toxoplasmosis lymphadenitis in the right parotid gland. Specific serum immunoglobulin tests suggested a current infection with Toxoplasma gondii. The patient was administered pyrimethamine and sulfadiazine for 4 weeks and underwent I-131 ablation for the functional thyroid remnants in the anterior neck. At a 16-month follow-up, the patient was clinically fit and recurrence free. This case highlights the importance of remaining clinically vigilant to differentiate an unusual metastatic carcinoma from inflammation of the parotid gland. A consideration of toxoplasmosis lymphadenitis by thorough history taking, appropriate serologic tests, and selective use of FNA may provide combined preoperative information for differential diagnosis of a parotid mass and help avoid an unnecessary surgical procedure.