Respiratory complications in cervical thymic cysts

Thymic cysts are considered uncommon lesions in the differential diagnosis of pediatric neck masses. They have been described as asymptomatic and of little clinical consequence. Recent reports have stressed the possibility of respiratory compromise associated with these lesions. We reviewed our experience with cervical thymic cysts with emphasis on respiratory problems. Ten pediatric patients underwent surgery and were found to have cervical thymic cysts. Ages ranged from newborn to 14 years. There were four boys and six girls. Two were found to have the thymic cysts at time of neck exploration for Grave's disease and hyperparathyroidism. Of the remaining eight patients, all had mobile cystic masses, located anterior to but extending beneath the lower third of the sternocleidomastoid muscle. The size of the mass ranged from 3.0 to 8.5 cm. Preoperative diagnosis included cystic hygroma/branchial cleft cyst (five), lymphoma (one), teratoma (one), and thymic cyst (one). All had a history of rapidly developing neck mass. Seven of the eight gave a history of upper respiratory tract infection (URI) prior to the development of the mass. Five had imaging studies that showed tracheal compression. Three of these required airway management in the early postoperative period. All were excised through a neck incision, with two requiring sternal extension. Histology showed cholesterol crystals, Hassall's corpuscles, and giant cell reaction diagnosis of thymic cysts. There has been no recurrence and no permanent respiratory sequela in the ten patients. Cervical thymic cysts are benign lesions that may be more common than literature suggests. This diagnosis should be entertained with neck masses that are located anterior to but with extension below the lower third of the sternocleidomastoid muscle. Respiratory compromise can indeed occur in these patients, especially with preoperative studies that demonstrate tracheal compression. In those children with tracheal compression, close postoperative respiratory monitoring is essential.