Cervical thymic cyst in the elderly: a case report

A Cervical Thymic Cyst in an Adult Female; A Case Report and Comprehensive Literature Review

Introduction: Cervical thymic cyst accounts for (0.3-1) % of cervical cysts in children and are usually present during the first decade of life with few reported cases in adults. Herein, we present a 34-year-old female with a cervical thymic cyst. We conducted a review of all the previously reported cases as well. Case presentation: The patient complained of an anterolateral neck swelling that was noticed one year ago. It was a soft, fluctuant, mobile, non-tender swelling in the midline and the right side of the lower neck. Neck ultrasonography revealed a large thin-walled cyst, with no internal septa, echoes, or solid parts. Post-contrast MRI of the neck showed a well-defined, oblong-shaped, lobulated cystic lesion just beneath the strap muscle. The cyst extended caudally to the superior border of the anterior mediastinum at the level of the upper border of the manubrium sterni. The patient underwent excision of the swelling under general anesthesia via Kocher's collar neck incision. Connection with the thymus gland was detected behind the manubrium sterni which was separated. Pathological examination showed prominent thymic tissue confirming the diagnosis of a cervical thymic cyst. Conclusion: Adult cervical thymic cyst is very rare with a few cases reported in the literature. Surgical excision in symptomatic patients is the treatment of choice. Paper's main novel aspects: • A rare presentation of a cervical thymic cyst in an adult. • A comprehensive literature review including all the previously reported cases in one table.

Cervical thymic cyst presenting as a possible cystic nodal metastasis of papillary carcinoma in a 53-year-old man

Cervical thymic cysts are rare embryonic remnants that develop along the course of thymic migration in the neck. They usually occur during infancy and childhood, and they are extremely rare in adults. We report a case of cervical thymic cyst in a 53-year-old man. The patient presented with a small mass of the thyroid gland and a cystic mass at the left level II area of the neck. On histopathology, the thyroid mass was identified as a papillary carcinoma and the left-sided neck mass was diagnosed as a cervical thymic cyst lined with nonkeratinizing, flattened squamous epithelium. The cyst wall contained atrophic thymic tissue composed of lymphoid cells, epithelial cords, and Hassall corpuscles. Although it is rare, cervical thymic cyst should be considered in the differential diagnosis of a lateral cystic neck mass in an adult.

Cervical thymic cysts in adults

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.

Cervical thymic cysts

Thymic cysts are rare embryonic remnants along the course of thymic migration in the neck or the anterior mediastinum which may result in cervical masses in children, often misdiagnosed. We present the experience gained by three European tertiary care medical centers in the treatment of thymic cysts as well as the current data on the embryology, clinical presentation, diagnosis and management of thymic cysts. A retrospective study was carried out in nine patients with thymic cysts during the period 1986-2002 at the departments of Pediatric Surgery of Children's University Hospital "Federico II" and "Santobono" Pediatric Hospital of Naples in Italy and "Aghia Sophia" Children's Hospital of Athens in Greece. All cases were asymptomatic, appearing mainly as masses resembling branchial cyst or lymphatic malformation. Laboratory and imaging investigations were not useful for preoperative diagnosis. In one case the mass extended into the mediastinum. The histological findings of thymic tissue and Hassal's corpuscles in the cystic wall were diagnostic. In all cases, surgery was successful and uneventful. Surgical excision was accomplished by dissection of the cystic masses from the jugular vein, carotid artery and vagus nerve and from the sternocleidomastoid muscle. The presence of a normal thymus in the mediastinum must be documented preoperatively in order to avoid the risk of total thymectomy. If a cervical thymic cyst extends into the normal thymus, attempts should be made to preserve the thymus, especially in younger patients. Thymic cysts should always be included in the differential diagnosis of lateral cervical masses, especially in children.