Background: Percutaneous ethanol injection (PEI) is used to treat cystic or mixed benign thyroid nodules. This treatment can result in rare complications, and three cases of Graves' disease (GD) without Graves' ophthalmopathy (GO) have been reported after PEI treatment of toxic thyroid adenomas. Here we present a 55-year-old male patient who developed GD and severe GO after PEI treatment of a mixed cystic-solid, nontoxic thyroid nodule.
Patient findings: Six months after PEI, the nodule volume had decreased from 8.9 to 3.0 mL, but we observed severe hyperthyroidism with elevated serum free triiodothyronine, free thyroxine, and thyrotropin receptor antibody levels. We also observed ophthalmopathy with symmetrical orbit and soft tissue involvement (grade b/c) and a clinical activity score of 4/7. The diagnosis of GO was confirmed by bilateral corneal damage, increased intraocular pressure on upgaze, and inconstant diplopia. A computed tomography scan showed that the inferior, medial, and superior extraocular muscles were bilaterally enlarged, the perineural space at the orbital cone was slightly reduced and the ophthalmic vein was congested.
Summary: A cause-effect relationship between PEI and GD/GO was likely in this patient because of the temporal sequence. Although the mechanism was unknown, we speculated that the thyroid tissue damage caused by PEI released a large amount of antigenic materials from follicular thyroid cells, including thyrotropin receptor protein, which triggered the autoimmune inflammatory response against the thyroid itself and the orbital soft tissues. The patient did not have any risk factors for either GD or GO.
Conclusions: This observation raises the concern, therefore, that unpredictable and severe complications, such as GD and GO, may occur in a few patients treated with PEI.