Case Report: Giant esophageal duplication cyst mimicking cardiac compression in an adult

Abstract

Background

Esophageal duplication cysts (EDCs) are rare congenital foregut malformations, accounting for only 0.5 to 2.5% of all esophageal masses. Although typically diagnosed during childhood, adult presentations are uncommon and frequently characterized by asymptomatic progression or non-specific clinical features. We report the case of a 58-year-old male presenting with atypical chest pain and anxiety. Multimodal imaging (CT and MRI) revealed a massive posterior mediastinal mass measuring 12 × 11 cm that exerted significant mechanical compression on the left atrium. The patient underwent a successful right posterolateral thoracotomy for surgical resection. Histopathological examination confirmed the diagnosis of an esophageal duplication cyst. The postoperative course was uneventful, with complete resolution of symptoms. Giant EDCs should be considered in the differential diagnosis of mediastinal masses in adults, even when presenting with atypical cardiovascular symptoms. Surgical resection remains the definitive treatment of choice to prevent long-term complications and establish a formal histological diagnosis.

Highlights

• What is the main finding? A giant (12 cm, 1,250 cc) esophageal duplication cyst in a 58-year-old male causing mechanical compression of the left atrium and mimicking cardiovascular disease.

• What does it add to the literature? This case documents an exceptionally large congenital duplication cyst presenting in late adulthood. It highlights the utility of multimodal imaging (CT, MRI, and echocardiography) in diagnosing rare mediastinal masses that cause extrinsic cardiac compression.

• What is the clinical implication? Giant mediastinal cysts should be considered in the differential diagnosis of atypical chest pain and cardiac symptoms in adults. Early surgical resection via thoracotomy is effective for symptomatic relief, prevention of complications, and definitive histopathological confirmation.

1. Introduction

Esophageal duplication cysts are rare congenital malformations of the foregut, with the earliest historical description attributed to Blasius in 1711 (1). These lesions represent between 0.5 and 2.5% of all esophageal masses (2) and are typically classified as either simple epithelial-lined cysts or true duplication cysts (3). While their exact etiology remains a subject of debate, they are generally associated with failures in the vacuolization process of the primitive esophagus during embryonic development (4, 5). Clinically, these malformations are most frequently diagnosed in pediatric patients; however, in adults, they often remain asymptomatic or present with vague symptoms that vary depending on the size and anatomical location of the mass (6, 7). For symptomatic cases, surgical resection is the gold standard of treatment to prevent complications such as infection, hemorrhage, or compression of adjacent vital structures (8, 9). Given the low incidence of giant cysts in adulthood and the inherent complexity of the mediastinal differential diagnosis (10), we present the case of a 58-year-old patient with a mass of exceptional dimensions.

2. Case presentation

2.1. Patient information and initial findings

A 58-year-old male farmer presented with a clinical history significant for recently diagnosed systemic arterial hypertension under pharmacological management. The patient reported past tobacco and alcohol use, both discontinued prior to evaluation, and denied any history of surgery, allergies, or blood transfusions. The current illness began with an onset of anxiety, upper extremity paresis, and atypical chest pain. Initial cardiovascular evaluation found the patient in stable general condition, adequately hydrated, with a blood pressure of 130/90 mmHg and oxygen saturation of 93%. Physical examination of the chest and abdomen revealed no pathological findings. Laboratory results were within normal limits, though the electrocardiogram demonstrated sinus rhythm with an incomplete right bundle branch block.

2.2. Diagnostic assessment

Coronary CT angiography was performed, which ruled out ischemic heart disease but identified a massive posterior mediastinal mass measuring approximately 12×11 cm (1,250 cc) (Figure 1A); this finding was subsequently confirmed by MRI (Figure 1B). A complementary echocardiogram documented a 67% ejection fraction and revealed that the mass exerted extrinsic mechanical compression on the left atrium.

Figure 1.

Preoperative radiologic evaluation of the giant esophageal duplication cyst. (A) Three-dimensional CT reconstruction identifying a massive posterior mediastinal mass measuring 12 × 11 cm (1,250 cc) and its anatomical relationship with adjacent cardiovascular structures. (B) Axial T2-weighted magnetic resonance imaging (MRI) confirming a large, well-circumscribed cystic lesion with high signal intensity, exerting extrinsic mechanical compression on the left atrium.

2.3. Therapeutic intervention

Based on these findings, the patient was referred to cardiothoracic surgery for a scheduled right posterolateral thoracotomy for lesion excision; an open technique was prioritized to ensure the integrity of the giant mass and prevent intraoperative rupture given its volume (1,250 cc), which was completed without complications. Intraoperative analysis was requested, cytological smears stained with H&E revealed cohesive clusters of benign ciliated columnar epithelial cells; these cells displayed distinct apical terminal bars with fine cilia and eccentric, normochromatic nuclei with elongated cytoplasmic tails, characteristic of respiratory-type epithelium (Figure 2A), no evidence of cytological atypia or malignant features was identified, supporting the intraoperative findings and reported as “negative for malignancy.” The surgical specimen was then submitted to the pathology department for formal analysis.

Figure 2.

Pathological and cytological characterization of the esophageal duplication cyst. (A) Intraoperative cytological smear (H&E) showing cohesive clusters of benign ciliated columnar epithelial cells; note the distinct apical terminal bars with fine cilia and eccentric nuclei, characteristic of respiratory-type epithelium. (B) Macroscopic appearance of cystic specimen; the internal surface exhibits a smooth, glistening mucosal lining with a gastric-like appearance, devoid of nodules. (C,D) Photomicrograph (H&E) demonstrating the cyst wall architecture, composed of two well-defined concentric layers of smooth muscle mimicking the muscularis propria of the esophagus. High-power view (H&E) of the epithelial lining revealing ciliated pseudostratified columnar epithelium of respiratory type with interspersed goblet cells and absence of cytological atypia.

Macroscopic examination revealed an ovoid cystic structure labeled “posterior mediastinal tumor” measuring 12.3 × 12 × 11.7 cm. The external surface was smooth, greyish-white, and had a firm-elastic consistency. Upon sectioning, a unilocular cystic cavity was identified with a 0.8 cm thick wall and a smooth, glistening internal lining; the contents consisted of a dense, transparent mucinous fluid. The internal aspect of the wall exhibited a mucosal surface with a gastric-like appearance, devoid of ulcerations or nodules (Figure 2B). Histological sections showed a cystic structure lined by ciliated pseudostratified columnar epithelium of respiratory type, containing interspersed goblet cells. The subepithelial loose connective tissue was sparse, showing an abrupt transition toward a wall composed of smooth muscle organized into two concentric layers, mimicking the muscular architecture of the esophagus (Figures 2C,D). No accessory structures, such as cartilage or glands, were identified, and there was no evidence of communication with the adjacent esophageal mucosa. To further characterize the epithelial lining and confirm its embryological lineage, immunohistochemical (IHC) profiling was performed. The epithelial cells demonstrated robust and diffuse nuclear expression of both SOX2 and TTF1 (Figures 3A,B). Additionally, strong cytoplasmic reactivity for CK7 was observed (Figure 3C), while MUC5Ac staining specifically highlighted the mucin-secreting goblet cells (Figure 3D). These IHC findings support a foregut-derived respiratory-type phenotype. The analysis ruled out atypia, dysplasia, or signs of malignancy; the final diagnosis was unruptured esophageal duplication cyst, completely resected. The patient demonstrated a satisfactory postoperative recovery and remained asymptomatic at 6 months follow-up, with no evidence of recurrence on control imaging.

Figure 3.

Immunohistochemical (IHC) profiling of the epithelial lining. Photomicrograph showing robust and diffuse nuclear expression of SOX2 (A) and TTF1 (B) in the ciliated columnar epithelium, confirming the foregut-derived respiratory phenotype; strong and diffuse cytoplasmic reactivity for CK7 throughout the epithelial layer (C) and MUC5Ac staining, selectively highlighting mucin-secreting goblet cells within the respiratory-type lining (D).

2.4. Patient perspective

“The onset of my illness was a sudden and deeply alarming experience; when I unexpectedly developed severe anxiety, weakness in my arm, and an unusual chest pain, I was absolutely convinced that my heart was failing due to my high blood pressure. It was a massive emotional shock when the doctors performed the scans and showed me that the true culprit was actually a giant cyst with a volume of over 1 l inside my chest. Although the prospect of undergoing major thoracic surgery was frightening, the moment the procedure was over, I felt an immediate relief, as if a physical weight had finally been lifted from my chest. Today, I am completely recovered, asymptomatic, and profoundly grateful to have regained my health and peace of mind.”

Timeline of the patient’s evaluation, intervention, and outcomes.

Date	Clinical event/episode of care	Key findings/interventions
2025-05-29	Initial clinical presentation	Onset of atypical chest pain, upper extremity paresis, and anxiety.
2025-06-03	Cardiovascular evaluation	BP: 130/90 mmHg, O2 Sat: 93%. Physical examination: normal. Electrocardiogram: sinus rhythm with incomplete right bundle branch block. Echocardiogram: 67% LVEF with extrinsic mechanical compression on the left atrium.
2025-06-05	Multimodal imaging	Coronary CT angiography: ruled out ischemic heart disease; identified a 12×11 cm posterior mediastinal mass (1,250 cc). MRI: confirmed a large, well-circumscribed posterior mediastinal cystic lesion.
2025-06-25	Surgical intervention and intraoperative analysis	Scheduled open right posterolateral thoracotomy for complete lesion excision. Intraoperative cytological smear (H&E): cohesive clusters of benign ciliated columnar epithelial cells; reported as “negative for malignancy.”
2025-06-27	Formal histopathology and IHC profiling	Gross and microscopic analysis: unilocular cyst lined by ciliated pseudostratified columnar epithelium with two smooth muscle layers. IHC: robust nuclear co-expression of SOX2/TTF1 and cytoplasmic CK7/MUC5Ac. Final Diagnosis: Esophageal Duplication Cyst (EDC).
2025-12-09	Long-term Follow-up (6 Months)	Complete resolution of symptoms (atypical chest pain and anxiety). Control imaging showed no evidence of recurrence.

3. Discussion

The pathogenesis of esophageal duplication cysts is linked to embryologic vacuolization failure between the 4th and 8th weeks of gestation (2, 5). Although approximately 60% of these lesions are located in the lower third of the esophagus, their presentation as a giant mass in an adult is an exceptional finding that poses significant diagnostic challenges. According to Shields’ classification of mediastinal compartments, esophageal lesions are typically located in the posterior (paravertebral) mediastinum, a location consistent with the anatomical origin of this mass (2, 4, 7). The clinical novelty of this case is defined by the triad of a substantial volume (1,250 cc), the mechanical mimicry of acute cardiovascular disease through left atrial compression, and a robust immunohistochemical confirmation of its foregut origin.

In adult patients, symptomatology is highly variable and strictly dependent on the lesion’s size and location. While cysts in the upper and middle thirds often present with respiratory symptoms, those in the lower third frequently cause compressive dysphagia (6, 8, 11). A distinguishing feature of this case was the presentation of atypical chest pain and anxiety secondary to extrinsic compression of the left atrium. Consequently, the initial clinical differential diagnosis included acute coronary syndromes and other posterior mediastinal masses, such as neurogenic tumors or lymphomas (1, 9, 10). These solid neoplasms were effectively excluded by multimodal imaging; CT and MRI demonstrated a well-circumscribed, unilocular cystic lesion with fluid density and high T2-signal intensity, lacking solid components or internal contrast enhancement (12, 13). Furthermore, the histopathological identification of a smooth muscle wall, alongside the total absence of atypical lymphoid populations or neural lineage tissue, provided definitive confirmation of the cystic nature over these solid alternatives.

Multimodal imaging is essential. Computed tomography (CT) identifies a cystic structure with fluid density and lack of contrast enhancement, aiding in the exclusion of solid neoplasms or aneurysms (12). Magnetic resonance imaging (MRI) further confirms the cystic nature due to high signal intensity on T2-weighted sequences (13). Endoscopic ultrasound (EUS) is considered the technique of choice for evaluating the cyst wall, allowing for differentiation from bronchogenic cysts (typically paratracheal) and pericardial cysts (usually located in the cardiophrenic angle) (13, 14). However, EUS was not performed in this case due to the urgent clinical need for surgical decompression of the left atrium, prioritizing the patient’s hemodynamic stability over additional diagnostic imaging.

From a histopathological standpoint, the diagnosis of an esophageal duplication cyst (EDC) is established based on the classic Smith and Bremer triad: proximity to or communication with the esophagus, a lining of gastrointestinal or respiratory epithelium, and a wall containing two distinct layers of smooth muscle (2, 3). Unlike other cystic lesions, EDCs exhibit a well-defined, concentric muscular organization that replicates the structure of the host organ, a feature clearly identified in the analyzed sections (3, 15). The primary diagnostic challenge is the bronchogenic cyst. Both entities often share a ciliated pseudostratified columnar epithelial lining—a result of metaplasia or their common origin in the primitive foregut—however, the bronchogenic cyst is definitively distinguished by the presence of hyaline cartilage, bronchial submucosal glands, or elastic tissue. These elements were entirely absent in our specimen (15). Furthermore, neuroenteric cysts must be excluded through a rigorous evaluation of the cyst wall and clinical context. Although they may present with ciliated epithelium, their wall structure is typically more disorganized and they are almost invariably associated with vertebral body anomalies or connections to the spinal canal, findings that were ruled out in this patient (16, 17). Complementing the morphological findings, the immunohistochemical profile—specifically the nuclear co-expression of SOX2 and TTF1—served as the fundamental evidence to confirm a foregut-derived respiratory phenotype (15, 18). Although TTF1 positivity could initially suggest a pulmonary lineage typical of a bronchogenic cyst, the robust expression of SOX2, alongside the presence of focal squamous metaplasia, strongly aligns with an esophageal epithelial differentiation. Ultimately, when these immunophenotypic findings are integrated with the definitive histological criteria—namely, the true double-layered muscularis propria and the absolute absence of hyaline cartilage or bronchial glands—the diagnosis is conclusively oriented toward an esophageal duplication cyst (2, 3, 15).

The age of presentation is a critical factor in the clinical suspicion of this pathology. Historically, the vast majority of esophageal duplication cysts are diagnosed during the neonatal period or within the first 2 years of life, typically presenting with respiratory distress or feeding difficulties (1, 17). In contrast, our 58-year-old patient represents an infrequent demographic presentation, as it is estimated that fewer than 30% of these cysts are detected in adulthood, and an even smaller proportion reach dimensions exceeding 10 cm (2, 7, 10). This prolonged clinical latency in adults suggests a slow and silent growth pattern. Unlike the pediatric presentation, where the restricted mediastinal space leads to acute symptoms, in adults, the cyst can expand gradually, reaching massive volumes of over 1,000 cc before the mechanical compression of vital structures—such as the left atrium in this case—prompts medical evaluation (4, 7, 10). Consequently, as highlighted in the systematic review of adult cohorts by Gonzalez-Urquijo et al. (18), the clinical and anatomical presentation in mature patients contrasts sharply with pediatric cases. While pediatric cysts trigger early respiratory or feeding distress within tight boundaries, adult lesions can achieve exceptional dimensions over time; this massive volumetric expansion inevitably distorts traditional anatomical borders, causing adjacent structures to shift and leading to significant diagnostic confusion regarding the mediastinal compartment of origin (18). Documenting such cases in mature patients is essential for thoracic surgeons and pathologists to maintain this entity within their scope of differential diagnoses, thereby avoiding confusion with rapidly growing malignant neoplasms (9, 10).

4. Conclusion

Giant esophageal duplication cysts should be integrated into the differential diagnosis of mediastinal masses in adults, particularly when clinical presentations mimic cardiovascular pathology. The integration of advanced imaging with detailed histopathological analysis is essential for a definitive diagnosis. Complete surgical resection is the treatment of choice, serving to relieve compressive symptoms, prevent long-term complications, and confirm the benign nature of the lesion (7, 9).

Funding Statement

The author(s) declared that financial support was not received for this work and/or its publication.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Ethics statement

Written informed consent was not obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article because the authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the Helsinki Declaration (as revised in 2013). Due to the retrospective nature of this case report, which utilized de-identified archived histopathological materials and electronic records, the requirement for written informed consent was waived by the Institutional Ethics Committee of Hospital Médica Campestre.

Author contributions

EA-G: Conceptualization, Formal analysis, Writing – review & editing. LP-U: Data curation, Investigation, Writing – review & editing. CG-V: Data curation, Investigation, Writing – review & editing. RT-G: Resources, Writing – review & editing. SS-A: Resources, Writing – review & editing. DO-R: Data curation, Investigation, Writing – review & editing. MD-C: Data curation, Investigation, Writing – review & editing. MM-P: Conceptualization, Formal analysis, Project administration, Supervision, Writing – original draft, Writing – review & editing.

Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declared that Generative AI was not used in the creation of this manuscript.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.