Tongue Root Cyst as a Manifestation of the Variant m.3243A>G.

There are indications that the frequency of cyst formation is increased in mitochondrial disorders (MIDs). Cysts can be found in various organs of MID patients but tongue root cysts have not been reported as a manifestation of a MID. In a 56-year-old male with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) manifesting with recurrent stroke-like episodes, seizures, cognitive impairment, ataxia, psychiatric abnormalities, bilateral visual impairment, bilateral hypoacusis, pre-diabetes, hyperlipidemia, myopathy, and lactic acidosis, an asymptomatic, pre-epiglottic cyst with 1 cm in diameter and protein-rich content in the right tongue root was accidentally detected on ultrasound and confirmed by MRI at the age of 50 years. The patient did not complain about dysarthria or dysphagia but had a mild cerebellar speech. The cyst was confirmed on an MRI six years later, without having changed in diameter, extension, or symptomatology. Due to the atypical location, a branchiogenic cyst was excluded. In conclusion, tongue root cysts may be a manifestation of the m.3243A>G variant.