Cervical Thymic Cyst Mimicking Laryngocele

Cervical thymic cysts are nearly 0.3% of all congenital cervical cysts. Thymic cysts are asymptomatic, but they rarely complain of dysphagia or tracheal obstruction symptoms. A soft, mobile, and painless mass increasing with valsalva maneuver directs the diagnosis of laryngocele. There has not been any study in the literature in which thymic cyst presenting like laryngocele. We hereby present a case of thymic cyst mimicking laryngocele that has not been reported so far. 1. Introduction Thymic cysts are rare lesions and may occur anywhere from mandible to mediastinum, along with the migration path of the thymus. However, they are mostly seen in the mediastinum. Thymic cysts are generally misdiagnosed as branchial cyst and cystic hygroma, since they may cause almost similar symptoms to cervical cysts. However, a thymic cyst mimicking a laryngocele is extremely unusual. We herein present a boy with a cervical thymic cyst mimicking laryngocele. To the best of our knowledge, this is the first case in the literature showing that a cervical thymic cyst presenting as a laryngocele in childhood age. 2. Case Report A 7-year-old patient admitted to our clinic with a painless mass on the right side of the neck, which was 2？cm in diameter (Figure 1). The detailed anamnesis revealed that the swelling occurred suddenly a few years ago and progressively increased in size thereafter. The patient did not have any other symptoms except for the sudden swelling. Physical examination disclosed a soft, mobile, and painless mass on the right side of the neck. With valsalva maneuver, it was observed that the mass increased in size and became visible (Figure 2). The patient did not complain of dysphagia, stridor, or dyspnea. Systemic physical examination was within normal limits. A successive computed tomography (CT) scan and magnetic resonance imaging (MRI) was performed which disclosed a cystic mass extending into the right hemithorax. Additionally in MRI, the cyst was in relation to the larynx (Figure 3). Based on the aforementioned clinical and radiological examinations, the patient was operated on with a preoperative diagnosis of a laryngocele. During the surgery, a 6？cm long horizontal skin incision beginning from the 4？cm superior of the right clavicle was performed. The cystic mass was made visible by dissecting the sternocleidomastoid muscle laterally and the platysma. The cervical part of the mass was dissected from the surrounding structures. It was seen that the mass was in very close proximity to the pyriform sinus, jugular vein, and internal carotid artery.