Uvod: Tireoglosalne ciste pripadaju najčešćim kongenitalnim malformacijama vrata. Nastaju zbog nepotpuna sraštavanja tireoglosalnog kanala. Predočavaju se kao otekline u središnjem dijelu vrata od korijena jezika do prsne kosti. Najčešće se dijagnosticiraju u mlađoj životnoj dobi. Lokalizirane su najčešće oko jezične kosti, a većina ih je smještena infrahioidno (65-80 %). Prikaz bolesnice: Žena, u dobi od pedeset šest godina javila se u hitnu otorinolaringološku ambulantu radi bolnosti desne strane vrata posljednjih dvanaest dana. Liječnik obiteljske medicine ordinirao je antibiotik kroz sedam dana, bol je regredirala, da bi se ponovno javila nakon nekoliko dana, te je ordiniran drugi antibiotik uz koji su tegobe perzistirale. Žalila se na oteklinu submentalno i bolno gutanje. U kliničkom statusu uočena je suprahioidna bolna oteklina, veličine 3 cm, uz bolno otvaranje usta. Učinjena je višeslojna kompjuterizirana tomografija vrata kojom je prikazana cistična tvorba iznad milohioidnog mišića. Upalni parametri su bili povišeni. Bili su prisutni i znaci okolnog celulitisa subkutanog tkiva submandibularne regije. Bolesnica je hospitalizirana, te je ordinirana parenteralna antibiotska terapija, na što je došlo do pada upalnih parametara i poboljšanja općeg stanja, te je peti dan hospitalizacije operirana. U općoj anesteziji učinjena je ekstirpacija medijalne suprahioidne ciste postupkom po Sistrunku. Bolesnica je nakon dva dana otpuštena na kućno liječenje uz peroralnu terapiju klindamicinom. Patohistološki nalaz upućivao je na upalno promijenjenu tireoglosalnu cistu. Na redovnim kontrolama otorinolaringologa, tri mjeseca nakon operacijskog zahvata, nije bilo znakova recidiva bolesti. Zaključak: Tireoglosalna cista dna usne šupljine je rijetka, osobito kod odrasle osobe u dobi od pedestšest godina. Potrebno je učiniti temeljiti klinički pregled, te diferencijalno dijagnostički razmišljati o tireoglosalnoj cisti kod bolesnika s oteklinom u području dna usne šupljine, a dijagnozu je potrebno potkrijepiti odgovarajućim dijagnostičkim metodama. Liječenje je kirurško uz empirijsku antimikrobnu terapiju. Pojava recidiva je rijetkost ukoliko je operacijski postupak proveden prema pravilima struke. Introduction: Thyroglossal cysts (TC) are most common congential neck malformations. They areresulting after incomplete thyroglossal duct obliteration. A TC presents as a neck swelling in medial linewhich connects the base of the tongue to the thyroid gland. They are most often diagnosed at childhood andare usually located around hyoid bone, mostly in the infrahyoid region (65-80 %).Case report: A fifty-six-years-old woman comes to the emergency ear nose and throat clinic because ofpain on the right side of the neck for the past twelve days. According to the family physician, an antibioticwas prescribed for seven days, the pain regressed and reapppeared after a few days, azythromycin wasprescribed, with which the complaints persisted. She had submental swelling and painful swallowing.Clinical examination found painful suprahyoid swelling, about 3 cm in size, with painful opening of the mouth. An MSCT of the neck was performed which showed a cystic formation located above the mylohyoidmuscle, in the medial line, with intense peripheral imbibition, measuring 3.3 × 1.5 cm. The formationoccupies the area of the middle and posterior third of the floor of the oral cavity and reached the hyoid boneat the back. Inflammatory parameters were elevated. There are also signs of surrounding cellulitis of thesubcutaneus tissue of the submandibular region. The patient was hospitalized with parenteral antibiotictherapy, after the decrease in inflammatory parameters and improvement of the general condition, she wasoperated on the fifth day of hospitalization. Extirpation of the medial suprahyoid cyst according toSistrunk's procedure was performed under general anesthesia. After two days, the patient was dischargedto home treatment with oral climycin therapy. The received pathohistological finding indicate aninflammatory TC. There have been no signs of recurrence at postoperatively follow-up.Conclusion: The TC of the floor of the mouth is a rare condition. It is necessary to take a thoroughclinical examination and think about a TC as a differential diagnosis in patients with swelling in the area ofthe floor of the oral cavity, which need to be proven by appropirate diagnostic methods. Treatment issurgical with empiric antimicrobial therapy. Recurrence is rare if the surgical procedure was performedaccording to surgical rules.