A 41 year old female was admitted to the hospital with the chief complaint of having been diagnosed with stage 5 chronic kidney disease on hemodialysis for nearly 2 years, and having discovered a space occupying lesion in the anterior mediastinum and a nodule in the upper lobe of the right lung for more than 1 year. The patient has been undergoing regular hemodialysis treatment in our hospital for stage 5 of chronic kidney disease in the past 2 years. A year and 9 months ago, Chest CT scan shows a space occupying lesion in the anterior superior mediastinum, measuring 6.0 × 3.5x4.9 cm in size, with a mixed cystic solid pattern and smooth edges (Fig. 1A a, b, c), At the same time, a ground glass nodule was found in the upper lobe of the right lung. We suggested that the patient should undergo surgical treatment, but the patient refused the surgery due to concerns about her poor physical condition. During follow-up, this pulmonary nodule increased in size from 9 × 7 mm 1 year and 9 months ago to 11mmx9mm before surgery (Fig. 1B a, b). The patient did not have symptoms of myasthenia gravis, but had a history of hypertension. After admission, physical examination, blood test, biochemical test, and tumor marker test were conducted, and the results are shown in Table 1. The results of lung function and heart function tests were both normal. The admission diagnosis of this patient is (1) Chronic kidney disease (stage 5); (2) Anterior mediastinal mass; (3) Right upper lobe nodule; (4) Hypertension (grade 3).

A Space occupying lesion in the anterior superior mediastinum, mixed cystic solid type (arrow), a horizontal plane, b coronal plane, c sagittal plane. B A nodule in the upper lobe of the right lung (indicated by the arrow), (a) shows 1 year and 9 months ago, and (b) shows 1 year and 9 months later

Preoperative evaluation showed that the patient's anterior mediastinal lesions and pulmonary nodules could be surgically removed, and this patient also required surgical treatment. Considering that the patient has uremia and poor tolerance to mediastinal and pulmonary surgery, multiple surgeries are not recommended, and the surgical time should not be too long. Therefore, we decided to perform CO2 inflation thoracoscopy via the subxiphoid process approach for thymectomy and right upper lobe wedge resection simultaneously at the same incision. We have made the following preoperative preparations: (1) The patient underwent routine hemodialysis treatment one day before surgery; (2) Localization of nodules in the upper lobe of the right lung before the start of surgery on the day of surgery. We adopted a localization method that the localization point of the lung can be observed both in imaging and thoracoscopy, and the operation steps are as follows: Firstly, cut a soluble medical absorbable haemostatic material into pieces and dissolve it in 10 ml of 50% glucose solution (Fig. 2a, b), Add 1 ml of 1% methylene blue solution and mix well to prepare a liquid with a certain concentration and blue color, and 5 ml of this liquid will be injected into the lung for localization of pulmonary nodule (Fig. 2c); Then, based on the location of the nodule in the right upper lobe of the lung on CT, we selected the puncture point at the third intercostal space of the right clavicle midline (Fig. 2e), because the level here is located about 3 cm below the level of the nodule in the right upper lobe of the lung. The depth of puncture is determined by measuring the thickness of the chest wall (Fig. 2d), and the depth of the puncture needle entering the lungs is approximately 0.5-1 cm. After successful puncture, the liquid we prepared was quickly injected into the lung tissue, followed by immediate chest CT examination. On chest CT, a nodular shadow similar to soft tissue density appears at the puncture site (Fig. 3a–c), which is located about 3 cm below the apical segment of the right lung nodule. This nodular shadow is the reference mark for determining the resection range of the right lung lesion during surgery, and due to its blue surface, it is easy to find under thoracoscopy during surgery (Fig. 3d).

a Absorbable hemostatic materials, b the absorbable hemostatic material was cut into small pieces and dissolved in glucose solution, c that methylene blue solution was added and mix well, d the measurement of puncture depth of the puncture needle from CT images, e the selection of puncture points

a–c The localized nodule in the upper lobe of the right lung on chest CT (indicated by arrows), while d shows the localization marker on the upper lobe of the right lung under thoracoscopy (indicated by arrows)

Surgical procedure: The patient was placed in a supine split leg position under general anesthesia with dual lumen tracheal intubation. An incision of about 3 cm was made under the subxiphoid to establish a sternal tunnel. A 10 mm puncture trocar was inserted and the incision was sutured to seal, then a thoracoscope was inserted from this port (Fig. 4A a). A 0.5 cm incision was made under both rib edges, with a 5 mm puncture trocar inserted (Fig. 4A b, c). A laparoscopic forceps was placed on the left side, and an ultrasonic scalpel was placed on the right side (Fig. 4B). The CO2 pressure was 10 mmHg, and the flow rate was 12 L/min. The surgery is divided into two parts: thymectomy and right upper lobe wedge resection.

Incision diagram, a represents the incision under the subxiphoid process, b, c represent the incisions under the rib margins on both sides, and d represents the incision in the 5th intercostal space of the left clavicle midline

The first part is to perform thymectomy. Firstly, fully incise the bilateral mediastinal pleura, free the front of the thymus, free the adipose tissue on both sides of the thymus and its surrounding areas in front of the bilateral phrenic nerves, free the lower pole of the thymus and the isthmus from bottom to top in front of the pericardium, expose the innominate vein, and expose the upper pole of the thymus on both sides above the innominate vein and cut it off. During the operation, we observed a large tumor in the anterior mediastinum that adhered to the left upper lobe of the lung (Fig. 5a). However, the outer membrane of the tumor was intact and did not invade the surrounding tissues (Fig. 5b). We added a 1.5 cm incision in the 5th intercostal space of the left clavicle midline (Fig. 4A d), inserted a 12 mm trocar (Fig. 4C), and placed a laparoscopic forceps from this port to pull the thymus to assist in completing thymectomy (Fig. 5c). The second part is wedge resection of the right upper lobe of the lung. Firstly, the blue stained area of the right upper lobe was discovered under thoracoscopy, which is the preoperative localization point (Fig. 3d). Based on this localization point, the resection range was determined. Subsequently, an endoscopic stapler with a 60 mm blue nail compartment was inserted from the trocar in the left fifth intercostal space, and a wedge resection of the right upper lobe of the lung was performed above the positioning point, with the cutting edge oriented horizontally (Fig. 5d). Finally, the excised thymic, lymph nodes and lung tissue were placed in a specimen bag and taken out from the incision under the subxiphoid process (Fig. 6a, b, c,d). Two closed thoracic drainage tubes with a diameter of 5 mm were inserted into the chest cavity through incisions below the rib edges on both sides, and the surgery was successfully completed. The surgical time is about 150 min, and the intraoperative blood loss is about 20 ml. The patient received bedside hemodialysis treatment on the 1st, 4th, and 7th day after operation. Due to persistent pleural effusion, the thoracic drainage tubes were not removed until the seventh day, and the patient was discharged on the 8th day. The hospital stay was 11 days, and the patient had no serious complications during the perioperative period.

a Adhesion between the mediastinal tumor and the left upper lobe of the lung, b the outer membrane of the tumor was intact and did not invade the surrounding tissues, c a laparoscopic forceps from 12 mm trocar to pull the thymus, d a wedge resection of the right upper lobe of the lung

a Lung tissue placed in a specimen bag, b the mediastinal tumor tissue placed in a specimen bag, c lymph nodes, d shows specimens of anterior mediastinal mass and pulmonary nodule: white arrow represents tumor tissue in the anterior mediastinum, and black arrow represents pulmonary nodule in the upper lobe of the right lung

Pathological diagnosis and follow-up: The pathological diagnosis of the anterior mediastinal mass is thymoma (b1 type), and no lymph node metastasis. The pathological diagnosis of the right upper lobe nodule is invasive lung adenocarcinoma (acinar type). Due to the fact that mediastinal tumor was R0 resected and the pathological type was B1 type thymoma which malignancy was relatively low, postoperative radiotherapy is not recommended. Because the pathological subtype of lung cancer was alveolar adenocarcinoma with low malignancy and low risk of recurrence and metastasis, patients did not receive anti-tumor treatment after surgery. Regular hemodialysis treatment was continued, and there were no signs of tumor recurrence during a follow-up period of nearly 2 years (Fig. 7).

Chest CT scan 2 years after surgery. The arrow in a indicates the original surgical site of the lung, while the arrow in b indicates the original surgical site of the mediastinal tumor