Thymic cyst in the neck

Diagnosis and management of ectopic cervical thymus in children: Systematic review of the literature

BACKGROUND/PURPOSE

Ectopic cervical thymus (ECT) is a rare cause of neck swelling in children. Our aim was to evaluate the diagnostic and management challenges of this condition.

METHODS

Systematic review of the literature (1997-2020) using PRISMA guidelines.

RESULTS

A total of 192 cases of ECT were identified. Forty-two cases (4 studies) were excluded because of insufficient data resulting in 150 cases (7 bilateral) in a total of 143 patients. ECT presented as a solid mass in 71 cases (10 incidentally found at autopsy, 33 conservatively managed and 28 excised) and as a cystic mass in 79 cases (all excised). A total of 165 imaging studies in 123 patients were performed (65 ultrasound scans (USS), 51 magnetic resonance imaging (MRI) scans and 49 computer tomography (CT) scans). ECT was diagnosed by imaging in 18.7% (23/123) of patients. Fine needle aspiration cytology or incisional/needle biopsy were performed in 16% (23/140) cases; a correct diagnosis of ECT was obtained in 52% (12/23) of those cases. There were no reports of malignancy in 143 specimens analysed. A normal mediastinal thymus was absent in 2.5% (1/40) of patients investigated.

CONCLUSIONS

ECT is a benign and relatively rare condition in children that is seldom diagnosed on imaging before tissue sampling or surgical excision. ECT might be the only active thymus in 2.5% of cases and careful consideration should be taken prior to its excision in young children. We recommend that ECT should be considered in the differential diagnosis of neck masses in children. Conservative management might be appropriate in selected cases and the presence of a normal mediastinal thymus in the thorax should be investigated before planning surgical excision.

Cervical thymic cyst in an adult

Cervical thymic cysts (CTCs) are unusual lesions, representing only 1% of cystic cervical masses. Diagnosis of this condition in adults is even rarer. We report a 34-year-old female who presented with asymptomatic progressively growing left-sided neck swelling. Neck ultrasound (US) showed a large cystic lesion with septation, compressing the ipsilateral vessels. Magnetic resonance imaging (MRI) confirmed the US findings. Surgical excision was performed which subsequently showed findings consistent with CTC. CTC in adult is extremely rare, with few reported cases identified in the literature. Thymic gland anomalies in the neck are the consequences of an arrest in the descent of the gland, sequestration of the thymic tissue, or failure of involution. The diagnosis of this condition is rarely done prior to surgical excision. The clinical presentation, radiologic imaging, surgical findings, and histologic appearance are all essential components to make the correct diagnosis of this very rare differential diagnosis of cystic lateral neck swelling.

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.

Ectopic Thymic Tissue Presenting as a Neck Mass in Children: A Report of 3 Cases

The presentation of ectopic cervical thymic tissue as an anterior neck mass is rare. We report 3 similar cases in 3 boys—2 who had a thymic cyst and 1 who had an ectopic cervical thymus. We discuss the radiographic presentation on ultrasound and magnetic resonance imaging in these cases. We also review the typical histologic picture; histology is the only way of diagnosing this condition.

Cervical ectopic thymus in a 9-month-old girl: diagnostic difficulties

Ectopic cervical location of the thymus is a very rarely diagnosed developmental disorder in children. This anomaly is usually manifested clinically as a neck tumor suggesting lymphadenopathy, which is also differentiated from more frequently occurring cervical cysts, angiomas, or malignant neoplasms. A decisive examination is the histopathologic assessment of the tumor, supported by necessary immunoassays. A diagnostic process is sometimes very difficult and the results are ambiguous; what is more, this process has a decisive impact on the child's future life. Therefore, a histopathologic evaluation performed by 2 independent pathologists should become the standard procedure. We present the case of a 9-month-old girl, in whom, after a difficult diagnostic process, ectopic cervical location of the thymus was diagnosed.

Cervical thymic remnants in children

OBJECTIVE

Define the clinical presentation, diagnostic value of preoperative imaging, surgical management, and outcomes of treatment of congenital cervical thymic remnants in children.

DESIGN

Retrospective cohort.

SETTING

Single tertiary care institution.

PATIENTS

20 children who underwent excision of cervical thymic remnant, 1975-2006.

MAIN OUTCOMES MEASURED

Utility of preoperative imaging to diagnose cervical thymic anomalies; success of surgical treatment of cervical thymic remnants.

RESULTS

A total of 20 children were identified, with an average age of 6.98+/-5.63 years. All ectopic thymus tissue was found in the embryonic distribution area associated with the third branchial pouch. Fourteen patients underwent excision of a cystic ectopic thymus. Four of these patients exhibited lesions isolated to the cervical region, and 10 patients displayed lesions involving cervicomediastinal areas. Six patients underwent excision of solid ectopic cervical thymus, and each of these was an unanticipated mass encountered during surgical dissection for other procedures. 83% of patients with solid ectopic cervical thymus presented at age 3 or younger. Physical exam and preoperative imaging correctly diagnosed thymic remnants in 15% patients. Resection of thymic remnants was successful in all patients, and there were no recurrences.

CONCLUSIONS

Though rare, thymic remnants should be considered in the differential diagnosis of masses presenting in locations associated with derivatives of the third branchial pouch. Though preoperative imaging is helpful in identifying the extent of these lesions, congenital thymic remnants prove difficult to diagnosis radiologically. Surgical excision is the diagnostic and therapeutic treatment of choice in the management of cervical thymic remnants.

Congenital neck masses

Congenital neck lesions reflect abnormal embryogenesis in head and neck development. A thorough knowledge of embryology and anatomy is critical in the diagnosis and treatment of these lesions. The appropriate diagnosis of these lesions is necessary to provide appropriate treatment and long-term follow up, because some of these lesions may undergo malignant transformation or be harbingers of malignant disease.