BACKGROUND: Three types of cervical thymic anomalies have been described: ectopia, thymic cyst, and thymoma. Thymic cysts are very rare causes of benign neck masses in adults and are usually not diagnosed before surgery. Their prevalence is less than 1% of all cervical masses, and they are usually noted in childhood. We systematically reviewed the literature concerning cervical thymic cysts (CTCs) in adults.
SUMMARY: We identified 36 adult patients with a CTC. Our analysis included age, gender, cyst size, location, type, symptoms, time from cyst appearance, treatment, pathology, and follow-up. The male/female ratio was 4/5, the mean age was 36 years. Most of the cysts were asymptomatic masses diagnosed by pathology. In only one case did the differential diagnosis include a thymic cyst. Surgery should be considered the treatment of choice, but the size and location of the lesion and its relationship to nearby vital structures should be defined as clearly as possible preoperatively. Excision can be made via a transverse cervical incision. It may be a demanding procedure because of the close anatomical relationship of the CTCs with the carotid sheath and major nerves of the neck (recurrent laryngeal nerve, glossopharyngeal nerve, hypoglossic nerve, and phrenic nerve), particularly if there is adherence of the CTC with those structures.
CONCLUSIONS: CTCs are uncommon lesions causing neck swelling and are often misdiagnosed preoperatively. Surgical excision and histological examination of the specimen usually makes the diagnosis. The existence of normal thymus gland in the mediastinum should be confirmed intraoperatively, but this is not critical in adult patients. A CTC should be included in the differential diagnosis of cervical cystic masses.