A 77-year-old woman with a history of hypertension was admitted to Pusan National University Hospital for an evaluation of progressively worsening shortness of breath, a symptom she had been experiencing for several months. A chest radiograph revealed a large mass at the apex of the thoracic cavity, and initial computed tomography (CT) scan showed a well-defined mass, measuring 6.2 cm, in the right upper hemithorax (Fig. 1A, B). Chest magnetic resonance imaging indicated a relatively well-encapsulated mass with numerous feeding vessels originating from the branches of the right subclavian artery. Based on these findings, a preliminary diagnosis of angioleiomyoma with hemorrhage and cystic changes was made. Surgical resection was subsequently performed for both diagnostic purposes and relief of symptoms.

Figure 1. (A) A mass-like lesion, measuring 6 cm×5 cm, is visible in the apex of the right pleura on a chest X-ray (indicated by arrow). (B) A contrast-enhanced chest computed tomography scan reveals a well- circumscribed hypervascular mass, measuring 6.2 cm×5.4 cm, located in the right upper hemithorax (indicated by the arrow).

In surgical scenarios in which vascular damage may occur, the right subclavian artery should be temporarily clamped. In the present study, to avert ischemic injury to the brain and spinal cord, a preoperative assessment of the blood supply to the brain vessels was conducted. Transfemoral cerebroangiography disclosed dominant flow in the left vertebral artery, suggesting ample collateral flow via the left posterior communicating artery and the vertebrobasilar junction (Fig. 2A–C).

Figure 2. (A) A contrast-enhanced chest computed tomography scan reveals a feeding artery originating from the right subclavian artery, as seen in the axial view (indicated by the circle). (B) The same feeding artery viewed from a coronal perspective (indicated by the circle). (C) Trans-femoral cerebroangiography was performed to assess the blood supply to the brain vessels, which demonstrated adequate collateral flow from the left side.

We planned to perform robotic-assisted thoracoscopic surgery (RATS) under general anesthesia. We also prepared for upper partial sternotomy in the event of visualization issues. However, this procedure was ultimately unnecessary.

To introduce the 4-ports RATS, the patient was positioned in a left semi-prone position. A 12-mm port incision, which served as the camera port, was made at the seventh intercostal space (ICS) along the mid-axillary line. An 8-mm port incision was then created at the eighth ICS, 8 cm anterior to the camera port. Another 8-mm port incision was made within the auscultatory triangle. Finally, a 15-mm assistant port was established between the camera port and the second port.

To facilitate lung collapse and the caudal shift of the diaphragm, carbon dioxide insufflation was employed, with a maximum pressure of 6–10 mm Hg. On the left, a Cadiere grasper was installed, while on the right, a Maryland bipolar forceps was placed.

A 6.2-cm mass was found embedded in the apex of the thoracic cavity. To ensure sufficient visibility for the safe dissection of the feeding vessels, needle aspiration was performed to reduce the tumor’s size. This was followed by a purse-string suture to prevent potential seeding or spillage events (Fig. 3A). Once adequate visualization of the field was achieved, the feeding vessels were ligated without causing damage to the adjacent vessels (Fig. 3B). The mass was then resected and sent for histopathological evaluation (Fig. 3C). The diagnosis confirmed that the mass was a schwannoma with tumor-free resection margins. The aspirated fluid contained several chronic inflammatory cells, but no cells with malignant features were observed. The patient was discharged without complications on the first postoperative day.

Figure 3. (A) Needle aspiration with a purse-string suture was performed to decrease the tumor size and to avert potential seeding or spillage incidents. (B) The feeding vessel was safely ligated without damaging the adjacent vessel. (C) The mass was safely resected and sent for histopathologic evaluation.

Appropriate written informed consent was obtained for the publication of this case report and the accompanying images.

An apicoposterior mediastinal mass, even if benign, necessitates complete surgical resection. This is because it can lead to the onset of symptoms resulting from the compression of peripheral nerves, such as the intercostal or sympathetic nerves [1-3]. Recently, minimally invasive surgery has gained popularity due to its numerous benefits, including reduced mortality and morbidity, improved quality of life, and shorter hospital stays [4-6].

In the present case, a provisional diagnosis was made of angioleiomyoma with hemorrhage and cystic changes. This was based on the presence of numerous feeding vessels originating from the branches of the right subclavian artery, as observed on preoperative CT images. Open surgery was ruled out due to the potential for bleeding and the challenges associated with manipulation in a confined space. In cases involving a large tumor (>6 cm), intraspinal extension, spinal artery involvement, history of thoracic surgery, or apical location in the thoracic cavity, the use of video-assisted thoracic surgery (VATS) could increase the risk of postoperative complications. These complications may include hemiplegia, excessive bleeding, and Horner syndrome [2,7].

RATS enables a minimally invasive approach that addresses the limitations of VATS, as it offers intricate maneuverability of instruments in deep, narrow spaces and provides a magnified 3-dimensional view. The robotic instruments offer a wide range of articulation and movements, and they also eliminate hand tremors, ensuring a reduction in surgical trauma and careful manipulation of the mass [4-6,8]. In cases like this one, in which numerous feeding vessels extend from the branches of the right subclavian and right vertebral arteries, RATS provides the advantage of precise dissection of these arteries. However, if the vessel has a full-thickness tear or is difficult to manipulate, and unexpected blood loss becomes unavoidable, the assistant may need to perform a swift conversion to open surgery.

Although RATS offers a wide range of articulation and motion, the superior aspect of the tumor can often be obscured by the presence of a large, tightly packed cystic mass. This is particularly problematic when dealing with an unidentified cystic mass, which could rupture during manipulation, potentially leading to the seeding or spillage of unexpected malignant cells. Despite the scarcity of reports on the intraoperative spillage of malignant cells during thoracic surgery, studies on early-stage epithelial ovarian cancer have indicated that intraoperative tumor rupture can negatively impact prognosis. Specifically, rupture has been associated with a shorter time to disease recurrence and reduced disease-specific survival following intraoperative capsule rupture [9].

The application of a purse-string suture, followed by sterile aspiration, could effectively prevent the seeding or spillage from the cystic mass. This technique facilitates (1) the softening of the cystic mass, which aids in the dissection of the peritumoral plane, (2) partial reduction through the release of the intratumoral component, and (3) the straightforward dissection of the mass protruding into the apex of the thoracic cavity.

A retrospective review indicated a 3.2% incidence of paraplegia resulting from injury to the vertebral artery during the resection of an apicoposterior mediastinal tumor, even when open surgery is performed [1,2,7]. However, in the present case, the tumor was successfully and completely resected without complications using the RATS approach. RATS is a beneficial surgical method for the removal of an apicoposterior mediastinal tumor, as it allows for precise dissection around the primary vessels. The application of a purse-string suture not only facilitates the partial reduction of the mass by releasing the intratumoral components, thereby easing the dissection of the peritumoral plane, but also effectively prevents seeding or spillage from the cystic mass.

Author contributions

JK participated in the conception of the work, data acquisition, and drafting of the manuscript. HYA and JL participated in the conception of the work and the editing and revision of the manuscript. All authors read and approved the final manuscript.

Conflict of interest

No potential conflict of interest relevant to this article was reported.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.