Ectopic cervical thymus: Recognising the characteristic 'embroidery yarn' appearance on ultrasound.

Introduction: The thymus normally forms in the neck from the third pharyngeal pouch and descends to its normal position in the mediastinum. Arrest of descent or sequestration of thymic tissue can occur at any point along its path leading to an ectopic thymus which can present as a neck mass, usually in the paediatric age group. Purpose and Case Report: Ultrasound is generally performed in the presence of a neck mass in children. Although a characteristic 'starry sky' appearance of the thymus has been described on ultrasound, it is not considered sufficiently specific and cross-sectional imaging with magnetic resonance imaging is usually performed. On magnetic resonance imaging, the ectopic thymus appears as a homogeneous T1 isointense and T2 hyperintense mass and may actually appear ominous due to the tendency of ectopic thymus to sometimes show diffusion restriction unlike the normal thymus. Subsequent invasive biopsy or surgical removal is usually necessary to rule out a neoplastic lesion. In our observation, the ultrasound appearance of thymus is sufficiently distinctive to be confidently diagnosed as ectopic thymic tissue. This appearance is similar to the high-resolution appearance of an embroidery yarn. The reason most radiologists are not aware of the same is because the normal mediastinal thymus is not usually imaged by ultrasound. Conclusion: An accurate diagnosis on ultrasound would mean avoidance of expensive cross-sectional imaging and invasive biopsy or surgical excision in favour of regular non-invasive follow-up ultrasound scans until the lesion involutes in late childhood.

Adult Cervical Thymic Cysts: A Narrative Review.

OBJECTIVE: Thymic cysts are rare benign neck masses, accounting for less than 1% of all cervical masses. This study aims to discern different presentations, investigations, and treatment options of thymic cysts in adults by reviewing prior published studies from January 2010 to October 2021 to bridge the knowledge gap since the last review by Michalopoulos in 2011. Moreover, we present a case of a 28-year-old male with a left cervical thymic cyst. DATA SOURCES: Data were obtained from a literature search using the ScienceDirect, PubMed, ResearchGate, and Google Scholar databases. METHODS AND RESULTS: This study retrospectively analyzes reported cases of adult cervical thymic cysts by collecting demographic data, patient presentation, duration, location, size, type of imaging, fine-needle aspiration, and surgical approach. Eighteen patients were included. Cysts were seen on the left (n = 9), right (n = 5), and midline (n = 4). The age of the patients ranged from 19 to 64 years. Most patients present with painless left-sided neck swelling. Computed tomography (CT) was the preferred imaging modality in most cases. Moreover, surgical excision was essential for therapeutic and diagnostic purposes. This study did not require institutional review board approval. CONCLUSION: Adult cervical thymic cyst is a rare etiology. Nevertheless, a painless left-sided neck mass with no clear lower border should uphold thymic cyst as a differential diagnosis. MRI and CT scans are the preferred imaging modalities for preoperative planning. Surgical excision is mandatory for treatment and histological confirmation. As of October 2021, around 54 cases of adult thymus cysts had been reported to the best of our knowledge and review.

Solid Ectopic Cervical Thymus: A Case Report.

The thymus gland is a lymphoid organ normally located in the superior anterior mediastinum. It can rarely present abnormally in other sites along the thymopharyngeal canal and it might cause difficulties in breathing and/or feeding. We present a case report of an ectopic cervical thymus of a 10-month-old male infant who was presented to the hospital with a swelling on the left side of his neck for nine months. Investigations raised suspicion about four differential diagnoses and a total surgical excision for histopathological confirmation was deemed mandatory. It is of great importance to consider ectopic cervical thymus in the differential diagnosis of pediatric neck masses to avoid unnecessary procedures and prevent possible complications.

Ectopic Cervical Thymus in an Adult: A Rare Presentation.

Ectopic cervical thymus is an essentially benign condition related to embryological development of the thymus and is exceedingly rare among the adult population. Precise and early diagnosis of the entity on high-resolution ultrasonography may help avoid further investigations and unnecessary surgical intervention. This case report describes the typical sonological appearance of ectopic cervical thymus in a 44-year-old male.

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.

Timo cervical aberrante: masa cervical pediátrica inusual, revisión bibliográfica y reporte de caso / Aberrant cervical thymus: unusual type of pediatric cervical mass, bibliographic review and case report

Las masas cervicales representan un desafío habitual en pediatría, que en su mayoría son de etiología benigna. Una de las causas menos conocidas es el timo cervical aberrante, una entidad clínica resultante de anormalidades en el descenso del timo a lo largo de su ruta habitual (tracto timo-faríngeo). Este es un cuadro frecuentemente mal diagnosticado, del que se desconoce su incidencia real. Actualmente, su incidencia relativa parece ir en aumento en conjunto con la disponibilidad de la ecotomografía. En Chile no hay registro epidemiológico de este cuadro ni existen reportes de caso documentados. En este artículo se presenta una revisión bibliográfica sobre masa cervical pediátrica y un reporte de caso de un paciente chileno.

Cervical masses constitute a frequent challenge in pediatric care, mostly which are of benign nature. One of the lesser known causes is the aberrant cervical thymus, which results from embryological abnormalities during the thymus descent through its normal route (thymo-pharyngeal duct). This is a frequently misdiagnosed syndrome, for which its real incidence remains unknown. Nowadays, its relative incidence is on the rise along with ultrasound availability. There is no epidemiological record or documented case reports of this entity in Chile. In this article we present a bibliographic revision on cervical mass and a case report from a Chilean patient.

Predicted miRNA-mRNA-mediated posttranscriptional control associated with differences in cervical and thoracic thymus function.

A secondary cervical thymus (CT) is present in the neck region in about 50% of human and mice. CT in mice is an independent and functional organ, which can be colonized by T lymphocyte progenitors and generate thymocytes that are selected by the T cell receptor repertoire following the positive and negative selection. However, CT and the main thoracic thymus (TT) have been shown in mice to have significant functional differences. In this study, we use transcriptional profiling to compare mRNA or miRNAs expression patterns in murine CT and TT. We used these data to perform functional enrichment of the expression signatures and reconstruction of posttranscriptional miRNA-mRNA interaction networks. For this purpose, we compared the transcriptome profiling of paired RNA samples of whole CTs, TTs and parathyroid gland (PT), which was used as an external group, from Foxn1-GFP;Pth-Cre;R26dTomato transgenic mice that differentially label CT and TT. As expected, CT and TT featured comprehensive transcriptome similarity and this suggests that these organs are subjected to correlated transcriptional control. Nevertheless, significant differences were also observed between TT and CT, characterized by 107 differentially expressed (DE) mRNAs, and in 13 DE miRNAs, that in turn established interactions. These results suggest that functional similarity between TT and CT is reflected in their transcriptional activity and that CT functional uniqueness might be under posttranscriptional control.

Bilateral ectopic cervical thymus presenting as a neck mass: Ultrasound and magnetic resonance imaging.

Ectopic cervical thymus (ECT) is a rare cause of neck mass in the pediatric age group. It is extremely uncommon in infants. Overall more than 100 cases have been reported in the literature, though fewer than 10% involved infants. Furthermore, ECT is usually unilateral and more frequently seen in men than in women. Ultrasound (US) is the preferred initial imaging modality, especially in pediatric neck masses given its wide availability, low cost and lack of radiation exposure. US can show the location, extension, and echotexture of the ECT. Magnetic resonance imaging (MRI) can be performed to verify the diagnosis and confirm communication between the ECT and the mediastinal thymus. Diffusion restriction can aid diagnosis when seen in a neck mass similar to that in the mediastinal thymus. Herein is described a case of bilateral ECT in a 2-month-old boy with associated US and MRI findings.

Ectopic cervical thymus: a clinicopathological study of consecutive, unselected infant autopsies.

OBJECTIVES: An ectopic cervical thymus (ECT) is regarded as a rare congenital anomaly; therefore, the optimal diagnostic and therapeutic strategy remains a debatable matter. We designed a study to elucidate the clinicopathological characteristics of ECTs in consecutive, unselected infant autopsies, to help guide case management. METHODS: We searched for ECTs in all of the 21 consecutive, unselected infant autopsy cases performed at our institution over a period of 3 years, and all ECT consensus diagnoses were confirmed by histological examination. The following clinical characteristics were evaluated in cases with ECTs: age, gender, birth week and weight, clinical symptoms due to the ECT(s), position on discovery of death, cause of death, ECT contribution to the cause of death, and concomitant congenital disorders. The anatomical features evaluated included the location, number, size, color, shape, and margins of the ECTs, and the presence of a mediastinal thymus. Histological findings of the ECT(s) and the mediastinal thymus were compared within each individual. Fusion of the parathyroid and the ECT was also investigated histologically. Spearman's rank correlation coefficient (ρ) and the corresponding P value were calculated to determine if there was an association between ECT diameter and age. RESULTS: We detected 10 ECT lesions in seven cases (33%) among the 21 infant autopsy cases. The ECT cases involved five boys and two girls, with ages ranging from 1 day to 4 months. There were no reports of a positive family history of sudden death or antemortem clinical symptoms due to ECT in any of the cases. The ECTs were considered incidental regarding the cause of death, with the exception of one case that was extremely rare. Most ECTs were localized to the inferior thyroid, ranging from 0.4 to 1.9 cm in size. Size demonstrated a significant negative correlation with age (ρ=-0.75 and P=0.034). CONCLUSIONS: This study revealed that ECT is an essentially benign anomaly that occurs frequently during the development of the thymus, and may disappear over the first few years of life. These results suggest a conservative approach to the management of ECTs would be appropriate.

Ectopic cervical thymus associated with infant death: 2 case reports and literature review.

An ectopic cervical thymus is a rare congenital anomaly that can be located anywhere along the developmental pathway of thymic descent. Most lesions manifest as a cystic mass and have an indolent course. Two fatal cases associated with ectopic cervical thymus in the form of a solid mass are presented in conjunction with a review of the clinicopathological characteristics of the solid form. This report emphasizes the importance of considering a diagnosis of ectopic cervical thymus in infants with neck masses, with or without obstructive symptoms, to prevent possibly fatal outcomes.