An intracardiac accessory thyroid gland mimicking cardiac tumor

RATIONALE An accessory thyroid gland (ATG) in the right ventricle is an extremely rare condition. Described herein are histological findings of ATG in the right ventricle found in a patient with a normal cervical thyroid gland. PATIENT CONCERNS A 53-year-old woman was referred to our hospital after experiencing intermittent precordial pain for 2 years. DIAGNOSES The mass in the right ventricle was diagnosed pathologically as ATG. INTERVENTIONS Complete excision was performed because of the patient's intermittent precordial pain and to exclude the possibility of malignancy. OUTCOME The patient's pain was resolved. No recurrence was observed during the 6-month follow-up. LESSONS After review and analysis of the case, we found that plain and contrast-enhanced computed tomography scans showed that the mass had a similar intensity and enhancement to a cervical thyroid gland, which we think may be a useful clue for making a preoperative diagnosis of ATG.