Presentation and Management of Cervical Thoracic Duct Cyst: A Systematic Review of the Literature

Introduction

The thoracic duct runs 38 to 45 centimeters from the cysterna chyli at L2 vertebral level to the lower cervical spine [1] — show reference 1.  The duct is 2 to 5 millimeters wide, and it carries lymph ingested with fat from the vascular bed of the gastrointestinal system and drains into the central veins of the neck [1,2] — show references 1, 2. Very rarely, a cyst develops from the thoracic duct, also called a lymphocele of the thoracic duct [3] — show reference 3. The pathology is very uncommon, even more so in the cervical segment, since among the limited reported cases, the majority have been documented as either a thoracic or an abdominal thoracic duct cyst [4] — show reference 4. Although not established, theories suggest that congenital thoracic duct weakness and inflammation-mediated degeneration of the duct can predispose to cyst formation [5] — show reference 5. Due to the limited number of cases reported, no gold standard treatment has been established for cervical thoracic duct cysts; however, both surgical and conservative management have been proposed. To our knowledge, this is the first review in the literature about cervical thoracic duct cysts. This study aims to contribute to the literature by summarizing presentations, management, and outcomes of reported cases of cervical thoracic duct cysts.

Methods

Study design

The guideline followed in this systematic review was that of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Any study with a reported case of a cervical thoracic cyst was included, provided that necessary information was given on the patient and the mass.

Data sources and search strategy

EMBASE, CINAHL, PubMed/MEDLINE, Cochrane Library, and Web of Science databases were all screened using the following ("Thoracic duct" AND Cyst OR Cysts AND Neck OR Cervical) keywords.

Eligibility criteria

Any study with a reported case of thoracic duct cyst found within the cervical region and published in English was deemed eligible. Information on the patient, as well as the characteristics of the cyst, was required. To avoid bias, any study published in predatory journals, identified using Kscien’s list, was excluded from this systematic review [6] — show reference 6.

Study selection process

The titles and abstracts of the enrolled studies were screened by two different researchers, attempting to identify papers based on the study's eligibility criteria. A third researcher was recruited to resolve any disagreements that might arise between the initial two researchers.

Data items

Data was collected on mean age, sex, type of study, country of study, presentation, type of symptoms, location of the cyst, size of the cyst, management, and outcome of each management.

Statistical analysis

Microsoft Excel Workbook sheet was used to record the extracted data. The Statistical Package for Social Sciences (SPSS) 26.0 software was used in further quantitative analysis. The data is presented as frequencies and percentages.

Results

Study selection

The systematic search first brought 39 papers. Out of the initial 39, three only-abstract studies were excluded without further screening. The remaining 36 papers had their titles and abstracts screened, which resulted in 25 papers being removed due to irrelevancy. No paper was excluded due to wrong designs. The remaining 11 [4,7-16] — show references 4, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 studies were checked for wrong outcomes and predatory publishing; however, none were found. This left 11 papers at last to be included in this systematic review. The PRISMA flow chart highlights more details (Figure 1).

Characteristics of the included studies

Among the 11 included studies, 10 (91%) were case reports, with only one (9%) study being a case series. The United States, with four (36.3%), and France, with two (18.2%) studies, contributed the most, followed by Greece, China, Finland, Norway, and Canada, each with one study.

Main findings

A total of 16 patients were included in this systematic review. The average age of the patients was 47.8 ± 17.8 years. There were nine (56.3%) females compared to six (37.5%) males, leaving one (6.2%) patient unspecified. Half of the patients were symptomatic, and pain was the sole symptom in four (25%) patients. Details on the baseline observation and follow-up of the cyst were done for six (37.5%) patients, followed by surgical excision in five (31.4%) patients, a low-fat diet for two (12.5%) patients, aspiration performed in one (6.2%) patient, and lastly, one (6.2%) patient who underwent both surgical excision and had also received a low-fat diet modification regimen. All (100%) patients had their mass in the left supraclavicular region. The outcome of 12 (75%) patients was to be discharged without complications, whereas one (6.2%) patient was observed to have a persistent mass, and three (18.8%) patients did not have their outcome mentioned (Tables 2 and 3).

Discussion

Apart from the right side of the upper extremity, the right side of the thorax, and the right side of the neck, the thoracic duct drains the lymphatics of the rest of the body [1] — show reference 1. An uncommon phenomenon related to the duct is a thoracic duct cyst, also called a lymphocele of the thoracic duct [3] — show reference 3. Theoretically, the cyst can arise throughout the length of the entire duct; however, it usually arises within either the thorax or the abdomen. A thoracic lymphocele of the cervical region is the rarest form [4] — show reference 4. A cervical thoracic duct cyst will present as a lateral neck mass arising from the supraclavicular fossa. In this systematic review, all 16 patients presented with a mass, either painful or not, within the left supraclavicular fossa. Bhalla et al. reported the youngest patient recorded in the literature with a thoracic duct lymphocele presenting in an 8-month-old boy [12] — show reference 12. According to Abelarado et al., the cyst tends to occur more frequently in females, and the average age among the patients presenting with the cyst is 49.8 years [15] — show reference 15. This is in accordance with the current study’s findings, as the average age was 47.8 ± 17.8 years, and the majority were females. No single factor has been identified as a cause of this pathology; however, inflammation-mediated degeneration of the duct wall and congenital weakness have been suggested, as well as any possible traumas [3] — show reference 3.

As previously mentioned, since the duct drains the left side of the neck, the cyst will present as a left-sided supraclavicular mass. Most patients with a thoracic duct lymphocele are asymptomatic [5] — show reference 5. Half of the patients in this systematic review were symptomatic, and the other half had no complaints. Symptoms are generally due to the compressive effect of the mass on adjacent structures and can include pain, dysphagia, 

cyanosis, and even respiratory distress [7] — show reference 7. In this study, four (25%) patients presented with pain alone, making it the most common symptom. Others, such as migraine headaches, dyspnea, and soreness, were also reported, with one patient suffering from both pain and dyspnea. Lymphoscintigraphy used to be considered the gold standard for diagnosis; however, with the advent of new high-resolution imaging techniques, this tool has become less popular [17] — show reference 17. Confirmation of the diagnosis is usually conducted during surgery, as histological analysis of the specimen can be beneficial. One way this is done is by staining the endothelial cells lining the thoracic duct to verify that the cyst is, in fact, a thoracic duct cyst [4,18] — show references 4, 18. According to Mattila et al., another way to diagnose a thoracic duct cyst is via puncture and subsequence analysis. Following aspiration, the aspirate will manifest as a milky fluid showing excess triglyceride in laboratory investigations and lymphocytes, neutrophils, and macrophages, among others [7] — show reference 7.

Regarding management, no single gold standard has been established. This is attributed to the low number of cases that have been recorded. As previously mentioned, aspiration, although usually performed for diagnosis purposes, can be sufficient to deal with the mass. In this review, only one of the patients had aspiration alone. Surgical excision of the thoracic duct cyst is another common way to manage the mass [7] — show reference 7. This was performed for five (31.4%) patients in this review. Interestingly, in some instances, and especially after deeming the mass nonneoplastic, patients are followed up and observed after they either refuse surgery or the physician doesn’t consider it necessary. This has been highlighted in six (37.5%) patients within this study’s population. Furthermore, patients were managed through diet modification and, more specifically, transitioning to a low-fat diet. This yielded a satisfactory outcome in the two patients who only received diet modification and in the one patient who underwent surgical excision followed by a transition to a low-fat diet. All different management methods yielded satisfactory outcomes, with patients discharged without complications in three-quarters of the cases. This was apart from one patient whose mass persisted since they underwent no management and were observed.

Conclusion

Patients with thoracic duct cervical cysts may be asymptomatic or present with pain. Both surgical excision and conservative management may yield satisfactory outcomes.