Congenital thymic cysts in children--mostly misdiagnosed

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.

Excision of rare adult cervical thymic cyst

Cervical thymic cysts (CTCs) represent 1% of all cervical cystic masses. A review of the literature found that CTCs are typically asymptomatic, with a propensity to be left sided. CTCs often require histological evaluation for diagnosis. A 27-year-old male patient presented to an outpatient otolaryngology clinic with worsening bilateral jaw and neck pain and an incidental right-sided neck mass found on cervical MRI. Preoperative differential diagnosis included venolymphatic malformation versus branchial cleft cyst. Histological examination of the excised specimen provided diagnosis of a CTC. Postoperatively, the patient reported improvement in cervical pain. CTCs are a rare cause of lateral neck mass in young adults. Typical presentation included neck enlargement with no symptoms or in some cases compressive symptoms. It is important to consider CTCs when formulating a differential for a lateral neck mass.

A Rare Case of a Cervical Thymic Cyst Presenting in Adulthood

The cervical thymic cyst (CTC) is a rare, benign neck mass that most commonly presents in the pediatric population. These entities can occur anywhere along the normal path of descent of the thymus from the mandible to the sternal notch, and extension into the mediastinum has been observed. The presentation of these masses is often characterized by a painless, enlarging neck mass in a child during the first decade of life. Although most patients are asymptomatic, abutment of the cyst against local structures has led to a variety of presentations including respiratory distress. These rare lesions are noted to have a male predominance and most commonly present on the left side of the neck. We present the rare case of a 19-year-old male who presented with a left-sided painless, cystic neck mass. He underwent a computed tomography scan of the neck which showed a large cystic mass in the left neck deep to the sternocleidomastoid muscle. Preoperatively, the diagnosis of an infected third branchial cyst was favored. The lesion was completely excised in the operating room. Final pathology was consistent with a CTC. The CTC is an uncommon benign process that often presents as an asymptomatic cystic neck mass. Knowledge of the clinical presentation, diagnostic process, and treatment of these rare lesions is essential for the Otolaryngologist.

Congenital Thymic Cyst: Antenatal Diagnosis and Postnatal Management

Thymic cyst is regarded as a rare anomaly, accounting for about 3% of all anterior mediastinal masses. It can be either congenital or acquired. Congenital thymic cysts are usually asymptomatic, with about 50% found incidentally in childhood or adolescence. We report a case of 1-month 23-day-old male baby who was antenatally diagnosed at 32 weeks' gestation. Spontaneous resolution did not take place in the antenatal or neonatal period; instead, there was an increase in size on follow-up imaging. The baby was successfully managed by surgical excision.

Thymic Cyst Popping Up in a Patient With Congenital Heart Disease

The unusual case of a thymic cyst emerging and rapidly expanding, mimicking hence a right atrial aneurysm in an asymptomatic patient with congenital heart disease is presented.

An adolescent with Graves' disease and thymic hyperplasia

A 14-year-old female presented to our hospital for a second opinion regarding a recent diagnosis of Graves' disease and a mediastinal mass. Four months prior to presentation, the patient developed difficulty with concentration. Historically she had been an A/B student; however, her school performance worsened suddenly, and she almost failed the eighth grade. One month later, she began complaining of increased sweating, diarrhea, difficulty with balance, jitteriness, and difficulty sitting still. During the previous 2 months, she had an increased appetite along with a 10-lb weight gain, increased hair loss, fatigue, and dry skin. Two weeks prior to her presentation, her mother noted that she had a "large neck mass." At that time, the patient complained of dysphagia and tenderness of the anterior neck on palpation, but she had no respiratory difficulties. In addition, she had no symptoms of fever or night sweats.

A case report of cervical thymic cyst and review of literature

We are reporting a case of 10-year-old female child with an asymptomatic left sided cystic neck mass who underwent surgical excision. She was diagnosed as having a cervical thymic cyst based on histopathologic findings. The review of available literature on thymic cyst has shown that cervical thymic cyst is a rare occurrence, but should always be thought of in the differential diagnosis of cystic masses in the neck especially presenting in children.

A pediatric case of life-threatening airway obstruction caused by a cervicomediastinal thymic cyst

Most patients with thymic cysts complain of a slowly enlarging, asymptomatic cervical mass. Only 6-10% suffer dysphagia, dyspnoea, stridor, cervical pain or vocal paralysis. In some rare cases sudden onset of severe dyspnoea or asphyxia is the first symptom, especially in neonates and small infants. We report a unique case of a 20-month-old child, who required emergency tracheal intubation due to asphyxia. Cervicomediastinal thymic cyst might need to be included in causes of life-threatening airway obstruction in young children.

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.

Acute respiratory failure revealing a multilocular thymic cyst in an infant: a case report

Introduction

Multilocular thymic cysts are rare benign lesions of the neck and mediastinum that can occur at any age. In children, multilocular thymic cysts are usually symptomatic after the age of 2 years and produce few symptoms. We present an unusual case of a multilocular thymic cyst diagnosed in a 3-month-old girl and causing severe respiratory failure.

Case presentation

A 3 month-old-girl, with a medical history of dyspnea and wheezing since the age of 20 days, presented in our pediatric intensive care unit for acute respiratory failure requiring mechanical ventilation. The chest radiograph showed thoracic distension without any other abnormalities. The diagnosis of severe asthma was initially suspected and the patient was treated by intravenous corticosteroids and continuous perfusion of salbutamol without any improvement. A chest tomography scan was performed and demonstrated an anterior mediastinal multiseptated cystic mass extending from the inferior face of the thyroid gland to the left cardiophrenic angle. Sternotomy and excision biopsy were planned urgently. The cystic mass was excised completely. The histopathological examination confirmed the diagnosis of a multilocular thymic cyst.

Conclusion

The particularities of our observation are the occurrence of a multilocular thymic cyst in a young infant and its presentation by a severe acute respiratory failure mimicking asthma.

Inspiratory stridor and dysphagia in two newborn infants caused by ectopic thymus tissue

We report two cases of ectopic cervical thymus, a solid thymic lesion, and a thymus cyst causing inspiratory stridor and mild dysphagia in the neonatal period. Because of the rarity of thymic dystopia, the two masses were initially misdiagnosed as more common entities, namely, lymph node enlargement and lymphangioma, respectively. The correct diagnosis was made only after surgical excision and histopathological examination. This case report is completed by a short review of embryogenic development, diagnostic procedures with differential diagnoses, and therapeutic outcome of ectopic thymus.

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.

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.

Cervicomediastinal Thymic Cyst: Report of a Case

Congenital thymic cysts are rare. Consequently, they are often misdiagnosed and not included in the preoperative differential diagnosis of neck masses. We report the case of a 7-year-old boy with a large cervicomediastinal thymic cyst to increase the awareness of this unusual entity. We discuss the clinical features, presentation, and pathogenesis of thymic cysts.

Efficacy of OK-432 local injection for the treatment of a neonatal branchial cleft cyst: a case report

We herein present a case of a neonatal cervical cyst, which was diagnosed prenatally, and markedly decreased in size and disappeared after a local injection therapy of OK-432. A 0-day-old boy had an abnormal prenatal ultrasonography scan suggestive of rt. cervical cyst, measuring about 25 mm in diameter at 29 weeks' gestation. At birth, an elastic soft mass, measuring about 30 mm in diameter, was found on the right side of his neck. Computed tomography (CT) scans showed a giant cyst, which extended from the upper level of epipharynx to the upper mediastinum, and the contents were air and fluid. At 20 days of age, ultrasonography (US)-guided needle aspiration was performed. The aspirated fluid contained no epithelial cells, but many lymphocytes and neutrophils based on a cytological analysis. After the local injection of OK-432 had been performed four times, the right neck cyst had almost completely disappeared on US scans. During the local injection therapy, we analyzed the other sample of the second aspiration fluid of the neck cyst. Several clusters of epithelial cells, columnar epithelium, squamous cells, and ciliated epithelium were thus cytologically observed. Therefore, a final diagnosis of a branchial cleft cyst was made. The local injection of OK-432 was thus found to be an effective treatment for branchial cleft cysts.

Imaging Evaluation of Pediatric Mediastinal Masses

Mediastinal masses in children are a heterogeneous group of asymptomatic to potentially life-threatening congenital, infectious, or neoplastic lesions that can present complex diagnostic and therapeutic dilemmas. This article presents the imaging features of the common mediastinal masses seen in the pediatric population. Classification of the masses is performed according to the traditional mediastinal compartment model, consisting of the anterior, middle, and posterior mediastinum. This scheme facilitates differentiation of the variety of disorders.

Familial thymic cyst

Thymic cysts are rare lesions of the anterior mediastinum or neck. The majority are asymptomatic, and the remainder are associated mainly with symptoms of dysphagia or dyspnea. Diagnosis is difficult before surgery. Cervical thymic cysts are relatively rare; age at presentation ranges from the neonatal period to adulthood, and the most frequent presenting sign is a lateral neck mass. Mediastinal thymic cysts are more common and account for 1% of all mediastinal masses. They tend to occur in the older age group and are usually detected incidentally on chest X-ray film or computed tomography scans. Dysphagia and dyspnea are the main symptoms. We describe two brothers, aged 5 and 8 years, with mediastinal thymic cysts that presented as low cervical masses and review the embryology, diagnosis and management of thymic cysts.

Multilocular cervical thymic cyst: an unusual neck mass in children

Thymic cysts are usually considered uncommon lesions in the differential diagnosis of neck masses. Approximately 100 cases have been reported to date and most of these cases have occurred asymptomatically. Herein, the authors report a 4-year-old boy with cervical thymic cyst, which was misdiagnosed preoperatively as conglomerated lymph nodes. The correct diagnosis was made after surgical excision and through determination of specific histopathological findings of the thymic cyst. The etiologic theories, differential diagnosis and the treatment of thymic cysts are discussed.

The thymus gland

This article reviews the embryology, physiology, and pathophysiology of the thymus. The anatomy of this lymphoid organ, the significance of the presence or absence of the thymus radiographically, and the role of the thymus in immunity are also reviewed. Finally, the pathologic presentation of thymic hypoplasia (DiGeorge syndrome) is discussed. Despite advances in modern science, little was known about the thymus, one of the body's key organs in the immune system, until 1961, when Dr. Jacques Miller performed thymectomies in mice. Then it became evident that the thymus played a key role in the body's defense against infection. Since that time, researchers have continued to examine the role of the thymus from fetal life through adulthood.

The first reported sudden fatality from pulmonary artery compression by a thymic cyst

A 21-year-old previously well female student presented to accident and emergency having woken in the early hours of the morning with severe chest pain. On arrival she appeared, very unwell and breathless. For 1 week she had complained of a severe upper respiratory tract infection associated with chest pain which had been attributed to pleurisy. There was a strong family history of coronary heart disease but no risk factors for venous thrombosis or history of drug abuse. Over the next few minutes she began to look moribund with breathlessness and confusion. During physical examination, which was normal apart from tachypnoea and tachycardia, she had a cardiac arrest.

Advanced cardiopulmonary resuscitation for electromechanical dissociation was commenced and after two cycles the rhythm changed to ventricular fibrillation. Tension pneumothorax was excluded by intercostal fine needle aspiration and an endotracheal tube inserted. After 20 minutes of resuscitation, sinus rhythm was restored with a blood pressure of 100/50 mmHg. Physical examination revealed no rash, normal abdominal examination and no abnormal respiratory signs. She regained consciousness and sat up in an agitated state for about 30 seconds. An arterial blood gas showed pO2 10 KPa, pCO2 4 KPa, pH 6.97, bicarbonate 7.3 mmol/litre. Haemoglobin was 12g/dl, total white cell count 18.2 (neutrophils 5, lymphocytes 10). Electrolytes were normal.

A chest radiograph and electrocardiogram were about to be taken when cardiac output was lost during another electromechanical dissociation arrest. Resuscitation was restarted having established central venous access, which showed a central venous pressure of about +10 cmH20. Over the next 30 minutes cardiac output could not be re-established and nearly an hour after the initial cardiac arrest the patient was pronounced dead.

Post-mortem revealed an 8.0 cm diameter non-communicating cyst in the mediastinum. This was adherent to the left atrium anteroinferiorly and there was external compression of the pulmonary artery anterosuperiorly. It was unilocular, tense, thin-walled and collapsed when punctured revealing a cloudy white serous fluid.

The trachea contained thick secretions consistent with resolving pneumonia and there were multiple pulmonary foci of consolidation. There were bilateral pleural effusions each measuring 300 ml and pulmonary oedema, but no evidence of pulmonary emboli. Otherwise, the heart, pericardium and cardiovascular system were normal apart from a small blood-stained pericardialeffusion.

Histological examination showed that the cyst had a thin fibrous wall and was lined by cuboidal cells. Immunohistochemistry showed that these cells were positive for the specific cellular antibodies CAM 5.2 and AUA 1 indicating an epithelial rather than mesothelial origin. These findings are consistent with tissue of thymic origin.

Imaging of cystic lesions

Cystic neck masses are varied in their histology and embryogenesis. Because neural, vascular, and lipomatous lesions may all appear cystic, a multimodality imaging approach can help identify these potential mimics. Developmental neck cysts include thyroglossal duct, thymic, and branchial cleft cysts, and teratomatous lesions or lymphangiomas. Although laryngoceles are acquired lesions, congenital anomalies (e.g., abnormally long saccules) may play a role in their formation. Lesion location is at least as important a determinant as morphology in formulating the differential diagnosis of a cystic neck mass. Midline cystic lesions are most commonly thyroglossal duct cysts, although dermoid tumors are also frequently midline. Squamous cell carcinoma metastatic to anterior triangle lymph nodes (Fig. 17), and cystic, necrotic schwanommas, can mimic the typical appearance of an infected second branchial cleft cyst. Posterior triangle lymphadenopathy and lipomatous lesions may resemble cystic hygromas. Cystic-appearing masses in the carotid space include neurogenic tumors, vascular thromboses, and carotid chain lymphadenopathy. Neural-based lesions typically occur posterolateral to the carotid artery. Necrotic lymphadenopathy may be suggested by lesion multiplicity, or by the presence of ancillary features, such as systemic symptoms, or the existence of a primary tumor. It must be emphasized that the primary role of the radiologist in head and neck imaging is to help stage disease and guide surgery. Despite clinical and radiographic analysis, the diagnosis of many lesions ultimately depends on image-guided or excisional biopsy.