Although the optimal surgical treatment for lung cancer has long been lobectomy, segmentectomy may become a standard treatment for early-stage lung cancer.1) Previous studies have shown that segmentectomy is oncologically comparable with lobectomy for early-stage lung cancer.2) Segmentectomy also has the advantage of preservation of lung function.2,3)
Segmentectomy requires a higher degree of skill than lobectomy for thoracic surgeons.1) Moreover, segmentectomy is often challenging when thoracic surgeons encounter anatomical anomalies during surgery. A displaced left apicoposterior bronchus (B1 + 2) is a bronchial anomaly that thoracic surgeons sometimes encounter.4) Although previous reports have described lobectomy for lung cancer with a displaced left B1 + 2, few reports have described segmentectomy for an anomalous bronchial branch.5–7) We herein report a case of successful left apicoposterior segmentectomy for lung cancer in a patient with a displaced segmental bronchus using video-assisted thoracic surgery (VATS) with the aid of recently developed advanced techniques.
A 70-year-old man with no symptoms and a history of diabetes mellitus and subsequent chronic kidney disease was referred to our hospital because an abnormal lung nodule had been detected by chest computed tomography (CT). Initially, the CT image revealed a pure ground-glass nodule that was thought to be benign (Fig. 1A). During 6 months of close follow-up, the nodule gradually developed a solid component. CT finally showed a part-solid ground-glass nodule measuring 22 mm (the solid component measured 8 mm) in the left apicoposterior segment (S1 + 2), which raised suspicion for malignancy (Fig. 1B). 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed hypometabolic activity (maximum standardized uptake value, 1.4). Distant metastases were not detected by whole-body CT or FDG-PET. The patient was referred to our department for surgical treatment.
The preoperative CT scan showed a displaced anomalous B1 + 2 branching from the left main bronchus behind the left main pulmonary artery (Fig. 2A, B). The patient was suspected to have early-stage lung cancer (cT1aN0M0-IA1) located in S1 + 2 with a left displaced anomalous B1 + 2.
Considering the patient’s comorbidity, we decided to perform left S1 + 2 segmentectomy. The surgery was conducted under four-port VATS. The displaced B1 + 2 was initially accessed by dissecting along the posterior side of the mediastinal pleura. We identified the displaced B1 + 2 and subsequently detected A1 + 2 branching along the displaced B1 + 2 from the left main pulmonary artery. After dissecting the hilar lymph nodes, the displaced B1 + 2 and A1 + 2 were exposed and cut respectively with a mechanical stapler (Fig. 3A). Several lymph nodes were analyzed by intraoperative frozen section and found to be negative for metastasis. Indocyanine green (ICG) was administered intravenously. The intersegmental plane was identified under near-infrared thoracoscopy. The surface of the whole left lung except that of the target segment turned green (Fig. 3B). Following the intersegmental plane suggested by systemic ICG injection, we completed left S1 + 2 segmentectomy with the use of mechanical staplers. The operation time was 130 minutes, and the blood loss was minimal. The postoperative course was uneventful, and the patient was discharged 4 days after surgery.
The pathological diagnosis was invasive adenocarcinoma. The dimension of tumor invasion was 16 mm. The surgical margin was negative, and all lymph nodes were negative for metastases. The pathological stage was p-T1bN0M0. At the time of this writing (8 months postoperatively), the patient was alive without recurrence.