A Diagnostic Dilemma of Esophageal Duplication Cyst in a Patient With Rectal Cancer: A Case Report

ABSTRACT

Mediastinal masses include a diverse group of entities arising from the different structures within or close to the mediastinum. We report a 60‐year‐old female with a history of rectal bleeding who was diagnosed with rectal cancer. During the staging computed tomography scan, a round hypodense mass was seen in the left upper lobe region in close contact with the superior mediastinum, with differential diagnoses of metastatic lesions and duplication cysts. In order to clarify the nature of the referred lesion, an ultrasonography‐guided fine‐needle aspiration was performed, and the cytology was negative for malignancy. The patient underwent posterolateral thoracotomy, and pathologic evaluation of the resected mass showed epithelial squamous cells and smooth muscle layers in the cyst wall compatible with esophageal duplication cyst (EDC). Our study aimed to alert physicians to take EDCs into account for the differential diagnosis of mediastinal masses. A comprehensive understanding of the clinical characteristics, diagnostic techniques, and therapeutic options of duplication cysts is crucial for early detection and appropriate management in the adult population.

Summary.

• Gastrointestinal duplication cysts are uncommon congenital anomalies that are often asymptomatic and diagnosed accidentally in adulthood. It should be noted that many benign conditions including duplication cysts can mimic other pathologic entities, including malignant lesions, especially in oncologic patients.

1. Introduction

Tumors of the mediastinum include a diverse group of entities arising from the different structures within or close to the mediastinum. Of all mediastinal lesions, two‐thirds are benign, half of them being located in the anterior mediastinum and the others distributed between the middle and posterior mediastinum [1]. Mediastinal cystic masses represent fluid‐filled, round, well‐marginated lesions that are lined by epithelium. They comprise a range of entities with different prognoses and overlapping radiological manifestations. They can occur in any compartment of the mediastinum [2]. Most of these lesions are asymptomatic and benign. Large cysts may result in symptoms due to compression of nearby structures. Foregut duplication and pericardial cysts are the most common mediastinal cystic lesions [3]. Foregut duplication cysts are often diagnosed on imaging as incidental mediastinal masses, accounting for 6%–15% of the primary mediastinal lesions [4]. Depending on their embryological origin, they are classified as bronchogenic, esophageal, and neuroenteric cysts. The majority of these are esophageal duplication cysts (EDC) (50%–70%), followed by bronchogenic cysts (7%–15%), and the remaining are neuroenteric cysts [5]. In this article, we present a 60‐year‐old female with rectal cancer who had a mediastinal mass that was diagnosed in the preoperative staging computed tomography (CT) scan.

2. Case Presentation

2.1. Case History/Examination

We report a 60‐year‐old female with a history of rectal bleeding who underwent colonoscopy, and an ulcerative lesion was seen at 5 cm from the anal verge. Biopsy showed moderately differentiated invasive adenocarcinoma of the rectum. A thoracoabdominopelvic CT scan was performed for the preoperative staging (T₃N_1b). During the staging, a round hypodense mass measuring 70 × 75 mm in size was seen in the left upper lobe region in close contact with the superior mediastinum (Figure 1).

FIGURE 1.

(A) Plain radiography of the chest showed a well‐defined soft tissue density in close contact with the mediastinum, causing tracheal deviation. (B) Thorax computed tomography scan showed a round hypodense lesion measuring 70 × 75 mm in size (arrow) in the left upper lobe region in close contact with the superior mediastinum and esophagus (asterisk).

2.2. Methods (Differential Diagnosis, Investigations, and Treatment)

The probable diagnoses were metastatic lesions and foregut duplication cysts. The patient had a past medical history of hypertension, diabetes mellitus, and hypothyroidism. She had no remarkable gastrointestinal or respiratory symptoms other than an occasional mild cough. In order to clarify the nature of the referred lesion, an ultrasonography‐guided fine‐needle aspiration (FNA) by an experienced interventional radiologist was performed. A hyperviscous turbid fluid was aspirated. The microscopic investigation revealed eosinophilic discharge and a few inflammatory cells. The microbiology culture was negative, and the cytology was negative for malignancy. The case was discussed with a multidisciplinary team, and the patient underwent posterolateral thoracotomy, and the mentioned cyst was resected (Figure 2). The patient was discharged from the hospital without any postoperative complications.

FIGURE 2.

(A) Intraoperative finding; the insertion of the cyst (white arrow) was under the aortic arc in the aortopulmonary window (asterisk). (B) The resected cyst.

2.3. Conclusion and Results (Treatment and Follow‐Up)

Pathologic evaluation showed epithelial squamous cells and smooth muscle layers in the cyst wall compatible with EDC (Figure 3). For the management of rectal cancer, she underwent total neoadjuvant therapy and then abdominoperineal resection. The pathologic evaluation showed moderately differentiated invasive adenocarcinoma without lymphovascular and perineural invasion. All resection margins were free of tumor. The pathologic stage was ypT₂N₀. She did not have any complications after surgery. She did not receive adjuvant therapy, and at the time of writing, she was undergoing postoperative surveillance without any problems.

FIGURE 3.

Histopathological findings of the resected specimen, showing esophageal squamous epithelium covered by a smooth muscle layer. (stain, hematoxylin and eosin; magnification, ×100).

3. Discussion

3.1. Mediastinal Metastasis of Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer‐related mortality [6]. The most common sites of CRC metastasis are regional lymph nodes, liver, bone, lung, and brain [7]. Mediastinal metastasis in CRC patients typically occurs in individuals with previous lung or liver involvement. A few cases of case reports have reported direct CRC metastasis to the mediastinum without the involvement of other organs [8, 9, 10]. Musallam et al. [9] reported a patient with an enlarged lymph node in the right paratracheal region, which was positive on fluor‐18‐deoxyglucose positron emission tomography scan. The patient subsequently had a mediastinoscopic biopsy, which confirmed metastatic adenocarcinoma. Meanwhile, pulmonary cystic metastases from colon cancer are uncommon. Eguchi et al. [11] reported a patient with metachronous sigmoid and lung cancers, who had a cystic lesion in the left lower lobe that changed to a nodular lesion over time. The video‐assisted thoracoscopic segmentectomy was performed, and the histopathological investigation revealed cystic lung metastasis from sigmoid colon cancer.

Cystic mediastinal lesions have provided a diagnostic challenge, particularly in distinguishing malignant masses [12]. To our knowledge, there is only one previous case report similar to our study. Martins et al. [13] reported a patient with sigmoid cancer, who had a posterior mediastinal hypodense lesion in the staging CT scan, suggestive of metastatic adenopathy. Endoscopic ultrasound (EUS) revealed an intramural homogenous and hypoechoic lesion in the upper esophagus, consistent with EDC. EUS‐FNA was performed to exclude metastatic disease, and the cytologic analysis showed clusters of squamous cells without atypia, supporting the EUS diagnosis. The patient was followed up with EUS as he remained asymptomatic.

3.2. Prevalence, Histopathology, and Clinical Presentations of Esophageal Duplication Cysts

EDCs are the most prevalent foregut duplication cysts and the second most common gastrointestinal (GI) duplication cysts following the ileum [5, 14]. They account for 0.5%–2.5% of all esophageal masses with a male‐to‐female ratio of 2:1 [15]. These rare congenital malformations are caused by aberrations in embryologic development during the 4th–8th gestational weeks [16]. Of these lesions, one‐third are located in the upper and middle portions of the esophagus, and two‐thirds are located in the lower third [5]. Cystic duplications are the most common form of esophageal duplications, followed by tubular duplications. While the majority of cystic duplications are noncommunicating, tubular duplications may sometimes have direct communication with the esophageal lumen [17]. EDCs are histologically characterized by a lining of GI tract epithelium: either nonkeratinizing squamous or ciliated columnar epithelium, accompanied by double layers of surrounding smooth muscle [18]. There have been reports of cases with heterotopic pancreatic, gastric mucosa, and Peyer's patches [15, 19, 20].

Approximately 80% of EDCs are diagnosed during childhood [16]. The remaining cases are diagnosed in adults, as reported in this case. Fewer than 7% of EDCs do not exhibit any symptoms until adulthood [21]. Most of these EDCs are found accidentally during the work‐up for irrelevant conditions [15]. However, size and location may affect the presenting symptoms. EDCs located in the upper esophagus may be associated with respiratory symptoms, including stridor, dyspnea, cough, respiratory distress, retrosternal discomfort, and mass effect. On the other hand, lesions in the lower portion of the esophagus are commonly presented with food impaction, vomiting, esophageal stenosis, and dysphagia. Although rare, in the presence of heterotopic gastric mucosa, hematemesis has also been reported [15]. Moreover, the literature has reported cardiac arrhythmias, bleeding, and rupture associated with complicated mediastinitis [5, 22]. Tomar et al. [23] and Agarwal et al. [24] documented two patients with EDC mimicking postinfectious bronchiectasis and pericarditis, respectively. Moreover, there is a report of an EDC perforating into the thorax, causing a pyothorax, and the final diagnosis was an EDC accompanied by squamous cell carcinoma (SCC) [25]. It is extremely rare for these cysts to undergo malignant transformation, and few cases have been reported. Jacob et al. [26] and Dai et al. [27] reported two 61‐year‐old patients presenting with weight loss and dysphagia who had mass lesions in the upper and lower third of the esophagus, respectively. In the first case, biopsy revealed EDC along with SCC, so chemoradiation was performed with a complete response. In the latter case, a transthoracic surgical resection was performed, yielding the same histopathological diagnosis.

3.3. Radiologic Manifestations of Esophageal Duplication Cysts

As there are no distinct clinical signs, radiographic imaging is required for diagnosis. In a systematic review of adult EDC cases, the most frequently used imaging modality was CT scan, followed by upper GI series, endoscopy, and EUS. Magnetic resonance imaging (MRI) was utilized in just 16% of cases [28]. On plain radiographs, a well‐defined soft tissue density mass may be seen close to the esophagus or causing mediastinum widening [15]. Barium swallow may show an EDC as a mass with a pressure effect on the esophagus [4]. The EUS reveals a periesophageal homogenous hypoechoic mass with a multi‐layered wall. EDCs often have smooth margins, and the muscularis propria of the esophageal wall is in direct contact with their wall [29]. There is controversy over the use of EUS‐FNA in the diagnosis of EDCs. The infection rate following EUS‐FNA has been reported as high as 14% in previous studies [30]. Thus, it should be used for lesions with ambiguous or atypical appearance, and those with suspicion of malignancy [15]. On endoscopy, EDCs manifest as submucosal lesions with intact esophageal mucosa [5]. Non‐contrast CT scan reveals a low attenuation lesion located adjacent to the esophagus, with a different degree of pressure on the esophageal lumen. An increase in attenuation could indicate complications such as pus formation or internal hemorrhage. Contrast‐enhanced CT scan helps differentiate EDC from the abscess or hydatid cyst [4]. The MRI demonstrates cystic characteristics of the lesion as well as a high signal mass on T2‐weighted imaging [15]. The EDC appearance is identical to bronchogenic cysts on CT or MRI, except that its wall may be thicker and in closer proximity to the esophagus. Tc‐99 m radionuclide scanning could be useful since it yields a positive result in 50% of patients with EDCs containing heterotopic gastric mucosa [2].

3.4. Therapeutic Approaches to Esophageal Duplication Cysts

The treatment of EDC depends on the presence of symptoms once the diagnosis has been made. The treatment of asymptomatic EDC is still controversial and lacks established guidelines. The possibility of malignant transformation has led some authors to recommend resection [5]. An asymptomatic EDC was successfully treated by laparoscopic surgery in a 26‐year‐old female who remained symptom‐free after a 3‐year follow‐up [31]. Another therapeutic approach is conservative management in asymptomatic patients. Versleijen et al. [32] reported a 37‐year‐old patient with an asymptomatic EDC with the largest diameter of 4.1 cm who was followed for 13 years without developing any symptoms and no cyst growth on routine EUS. EUS surveillance is advocated over surgery in asymptomatic individuals, although its cost implications also must be considered.

Surgical excision is often the preferred option in symptomatic patients. Open and minimally invasive approaches, including laparoscopic and video‐assisted thoracoscopic surgery (VATS), have been shown to be effective and safe in the complete resection of these lesions [28, 33]. Typically, the cyst does not have any communication with the esophageal wall, so caution must be paid to avoid perforating the esophageal mucosa. Partial cyst excision can be performed in challenging cases [16]. Robotic‐assisted thoracoscopic surgery (RATS) has drawn more attention in recent years, with case studies showing promising results [34, 35]. Moreover, endoscopic submucosal tunnel dissection (ESTD) represents a novel and challenging therapeutic approach [36].

4. Conclusion

In conclusion, this study delineates a rare entity in an adult patient, illustrating the challenges associated with differential diagnoses of mediastinal lesions. It should be noted that many benign conditions, including duplication cysts, can mimic other pathologic entities, including malignant lesions, especially in oncologic patients. A comprehensive understanding of the clinical characteristics, diagnostic techniques, and therapeutic options of duplication cysts is crucial for early detection and appropriate management in the adult population.

Author Contributions

Marzieh Rahimi: writing – original draft, writing – review and editing. Farzaneh Mollanorouzi: resources. Fatemeh Shahabi: writing – original draft. Amir Hossein Jafarian: resources. Davod Alavi: resources. Reza Rezaei: conceptualization, resources, supervision.

Ethics Statement

This case report was composed following the obtaining the patient's informed consent for its publication. No additional diagnostic tests or therapeutic interventions were conducted specifically for this case report.

Consent

Written informed consent was obtained from the patients to publish this case report and any accompanying images. The written consent is available for review by the Editor‐in‐Chief of this journal.

Conflicts of Interest

The authors declare no conflicts of interest.

Rahimi M., Mollanorouzi F., Shahabi F., Jafarian A. H., Alavi D., and Rezaei R., “A Diagnostic Dilemma of Esophageal Duplication Cyst in a Patient With Rectal Cancer: A Case Report,” Clinical Case Reports 13, no. 10 (2025): e70978, 10.1002/ccr3.70978.

Data Availability Statement

The data supporting the findings of this study are available upon reasonable request from the corresponding author.