Endocrine Abstracts

Introduction: Thyroid swelling is habitually a thyroid nodule, however sometimes it reveal to be another pathology that we did not expect. We aim through this case and literature revue discuss the diagnostic errance in front of thyroid mass that it correspond to a cyst of the fourth cleft.

Material and method: We report a case of cyst of the 4^th cleft in adults managed in our department that presented as a thyroid nodule.

Case report: This is a 58-year-old man, with no notable pathological history, referred to our department for a right basicervical swelling evolving over two months. There was no signs of infection nor compression. Clinical examination revealed a painless 4 cm-sized mass located in the right basicervical region. It was mobile with swallowing conferred to the diagnosis of thyroid nodule. No other cervical mass was found. The rest of the ENT examination was normal. Cervical ultrasound showed a right laterocervical cystic mass closely to the right thyroid lobe sized 68×42×35 mm. Fine needle aspiration suggested the diagnosis of a branchial cyst. The patient underwent a hypopharyngoscopy that did not show any fistulous orifice of the piriform sinus. A right loboisthmectomy with the cyst excision was then performed. Histopathological examination confirmed the diagnosis of a cyst of the 4th cleft. No recurrence was observed after three years of follow-up.

Discussion/Conclusion: The fourth cleft cyst is a congenital malformation that is a challenging for the pratician. It is habitually revealed at an early age and frequently presented as a thyroid abscess. Endoscopy is necessary to research an eventual internal orifice of the fistula that explained the infection. In our case, the cyst has mimed a thyroid nodule and the absence of history of infection is explained by the absence of the internal orifice. Treatment is surgical, however cauterization of the internal orifice can be an alternative in cases of surinfected cyst when dissection closely to the recurrent nerve seems to be laborious.

Disclosure of interest: none declared