Fourth Branchial Cleft Cyst: An Important Differential Diagnosis in Lateral Neck Masses.

Branchial anomalies are a result of abnormal development during embryogenesis and are a rare cause of lateral neck masses of congenital origin. The second branchial cleft is the most common site of origin, with abnormalities arising from the first, third, and fourth clefts being rarer. Although cysts originating from branchial clefts are infrequent, it is important to consider this pathology in the differential diagnosis of neck masses, particularly those located laterally. This article discusses a rare case of a 49-year-old female patient who presented with the sudden appearance of a lateral neck mass after sports practice. The patient underwent extensive diagnostic studies, including radiological studies, which were compatible with a fourth branchial cleft cyst. The patient remains asymptomatic, and possible surgical treatment is being evaluated by the head and neck surgery service. This clinical case highlights the importance of prompt diagnosis and appropriate management of rare pathologies such as branchial cleft cysts.