BACKGROUND: Melkersson-Rosenthal syndrome (MRS) is a rare disorder of unknown 
cause. The classical triad of MRS is orofacial edema, recurrent facial 
paralysis, and a fissured tongue.
PATIENT: We present a 9-year-old girl with a recurrent peripheral facial 
paralysis. She experienced the first episode of a peripheral facial paralysis on 
the same side without orofacial swelling and lingua plicata 1 year ago. She was 
diagnosed with Hashimoto thyroiditis 9 months earlier, as confirmed by an 
endocrinologic investigation.
RESULTS: While the patient was hospitalized with recurrent facial paralysis, we 
found that serum levels of free thyroxine (1.3 ng/dL) and thyrotropin (0.4 
uIU/mL) were within normal range, but the level of antithyroperoxidase 
antibodies (772.0 IU/mL) was very increased. She had been taking an oral 
prednisolone orally for 2 weeks. At the 1-month follow-up, the patient's 
symptoms had completely disappeared.
DISCUSSION: The possible correlation between MRS and autoimmune disorders has 
been documented in only one report, which described an adult with autoimmune 
thyroiditis (Hashimoto thyroiditis) and MRS. We suggest that the co-occurrence 
of MRS and Hashimoto thyroiditis is not coincidental but linked to autoimmunity.