Thoracoscopic right apical segmentectomy in a patient with tracheal bronchus: a case report and review of literature

Abstract

A 70-year-old female patient was referred to our department for further abnormal chest shadow assessment in the right upper lung field. Computed tomography (CT) imaging detected multiple ground-glass nodules, resulting in primary lung cancer suspicion with no evidence of nodal involvement or distant metastasis. Three-dimensional CT revealed the presence of tracheal bronchus, directly branching off the right B1 bronchus from the trachea. Anomalous venous return was not observed. The patient was preoperatively diagnosed with cStage IA1 lung adenocarcinoma (cT1miN0M0) and underwent thoracoscopic S1 segmentectomy of the right upper lobe. Apical segmental bronchus was directly resected from the trachea, as expected based on preoperative CT examination. Pathologic diagnosis was pStage IA1 lung adenocarcinoma (pT1miN0M0). Multiple synchronous primary lung cancers were observed. The postoperative course was uneventful, and the patient demonstrated no recurrence at the 3-year postoperative follow-up. Tracheal bronchus is a rare abnormality observed in only 1% of patients undergoing thoracic surgery. Thoracic surgeons should be aware that preoperative planning based on three-dimensional CT is crucial in patients with tracheal bronchus because of potential issues associated with anomalous venous return. Good planning will contribute to safe segmentectomy in such cases.

Introduction

Tracheal bronchus is an uncommon abnormality observed in only 1% of patients undergoing thoracic surgery [1]. It is associated with anomalous venous return and other issues. Here, we present a patient with tracheal bronchus who underwent thoracoscopic apical (S1) segmentectomy of the right upper lobe.

Case report

A 70-year-old female patient was referred to our department for further abnormal chest shadow assessment in the right upper lung, noticed during a routine medical check-up. Hypertension, dyslipidemia, and chronic renal dysfunction are her medical history. She smoked until 65-year-old (one pack/day for 30 years). Computed tomography (CT) scan revealed a 1.4-cm ground-glass nodule (GGN) in the apical (S1) segment of the right upper lobe, which gradually increased and exhibited a solid component, and a small pure GGN near the posterior (S2) segment over the past 3 years (Fig. 1a, b). These lesions were considered primary lung cancer with no evidence of nodal involvement or distant metastasis. Three-dimensional CT detected a tracheal bronchus that directly branches off the right apical segmental bronchus from the trachea, 1 cm above the carina (Fig. 2a, b). The anterior (S3) and S2 segmental bronchi originated from the right main bronchus. The present case demonstrated no anomalous venous return, associated with tracheal bronchus. She was preoperatively diagnosed with cStage IA1 lung adenocarcinoma (cT1miN0M0) and underwent thoracoscopic S1 segmentectomy of the right upper lobe.

Fig. 1.

Computed tomography scans. A 1.4-cm ground-grass nodule in the apical (S1) segment of the right upper lobe. B Small pure ground-grass nodule near the posterior (S2) segment is indicated with a red circle, and V2a is indicated with a red arrow

Fig. 2.

Three-dimensional computed tomography (A, view from the back; B, view from the right) showing tracheal bronchus, which is observed as direct branching of the right apical segmental bronchus from the trachea 1 cm above the carina. The anterior (S3) and posterior (S2) segmental bronchi originate from the right main bronchus. No anomalous venous return is observed

The apical segmental bronchus branched directly from the trachea, as expected from the preoperative CT examination (Fig. 3). First, V1a and A1 were dissected, and then divided using a stapler. Subsequently, apical segmental bronchus was divided using a stapler. The Intersegmental plane was determined using indocyanine green and separated using a stapler. Partial merge resection of the S2 segment was performed using V2a as the landmark and encompassed the small pure GGN near the S2 segment of the right upper lobe. The operation time was 279 min and blood loss was 23 mL.

Fig. 3.

Intraoperative image. Apical segmental bronchus is directly branching from the trachea

The patient was pathologically diagnosed with multiple synchronous primary lung cancer. The cranial lesion in S1 indicated a stage IA1 lepidic adenocarcinoma (pT1miN0M0), and the dorsal lesion in S1 was stage 0 adenocarcinoma in situ (pTisN0M0). The patient demonstrated a good postoperative course. The chest tube was removed on 2 days postoperatively, and she was discharged 6 days postoperatively. The 3-year postoperative follow-up evaluation revealed that the patient was doing well and with no recurrence.

Discussion

The tracheal bronchus, which typically originates from the lateral tracheal wall, superior to the carina, is most predominantly situated approximately within 2 cm from the carina, and it is on the right side in the majority of the cases [2, 3].

There are three types of tracheal bronchus: displaced, supernumerary, and true [4]. The tracheal bronchus is classified as displaced in cases where the right upper lobe bronchus bifurcates and as supernumerary in cases where it trifurcates. True tracheal bronchus displaces the entire right upper lobe bronchus. Displaced tracheal bronchus is the most prevalent type, comprising approximately 80% of all tracheal bronchi [5].

The tracheal bronchus is associated with anomalous venous return; therefore, three-dimensional CT should be carefully evaluated preoperatively in patients with tracheal bronchus. Two studies reported displaced tracheal bronchus with anomalous venous return, revealing that part of the upper pulmonary vein was traveling behind the right upper pulmonary artery in both cases [6, 7]. The present patient had displaced tracheal bronchus without anomalous venous return; therefore, the usual vascular approach was performed during surgery.

Care should be taken during endotracheal intubation. Left-sided double-lumen endotracheal tube, which is usually used in lung surgery, can obstruct the tracheal bronchus and cause right upper lobe atelectasis and hypoxemia. Special care should extend to patients with tracheal bronchus that branches from > 2 cm above the carina [8]. Such cases may use a bronchial blocker instead of a left-sided double-lumen endotracheal tube [9]. Furthermore, Cho et al. reported a case of misrecognizing the carina and the site between the tracheal bronchus and the right main bronchus [10]. This case incidentally underwent right-side intubation, with the left main bronchus orifice sealed with the bronchial cuff. Accordingly, anesthesiologists should be informed in advance regarding the existence of tracheal bronchus.

Several studies have reported tracheal bronchus malignancies. A literature review revealed that these include squamous cell carcinoma (52%), carcinoid (19%), and other malignancies (29%), such as adenocarcinoma, small cell carcinoma, large cell carcinoma, and poorly differentiated carcinoma [4]. The present case was pathologically diagnosed with adenocarcinoma. Adenocarcinoma at this location may become more frequent in future due to the increasing number of nonsmokers diagnosed with adenocarcinoma afforded by advances in CT imaging despite a rare tracheal bronchus malignancy. Adenocarcinoma in tracheal bronchus has been reported more frequently in recent years [6–8, 11].

Japan Clinical Oncology Group 0802 and CALGB140503 studies revealed the survival and clinical benefits of segmentectomy in patients with peripheral non-small cell lung cancer of < 2 cm [12, 13]. These clinical trials revealed more segmentectomies required for peripheral small lung cancer based on their results. Correspondingly, a higher incidence of segmentectomy related to tracheal bronchus is expected, with the increasing importance of preoperative three-dimensional CT simulation. Safe surgery is possible by carefully analyzing the preoperative three-dimensional CT and considering the possibility of vascular anomaly associated with a tracheobronchial anomaly, as shown in the present case.

We conducted a literature search of English articles about a surgical case of lung cancer with tracheal bronchus published from January 1998 to March 2024 on Pubmed to further investigate the features of tracheal bronchus, pulmonary venous branching patterns, pathologic tumor types, and surgical techniques in surgical cases of lung cancer with tracheal bronchus (Table 1) [4, 6–8, 14–19]. We determined one case series and nine case reports. The tracheal bronchus was on the right side and branched directly to the right apical segment from the carina in the majority of cases. All, but four, were displaced tracheal bronchus. Four cases exhibited an anomalous venous return whereas ten cases demonstrated an unknown pulmonary venous branching pattern. A part of the superior pulmonary vein was running dorsal to the pulmonary artery in all these cases. Squamous cell carcinoma was the most prevalent pathologic type. Reports of segmentectomy have been prominent in recent years.

Table 1.

Summary of previous surgical cases of lung cancer with tracheal bronchus published from January 1998 to March 2024 on Pubmed

No.	Reference	Year	Age	Sex	Type	Position	Supply	Anomalous venous return	Tumor region	Tumor size (mm)	Surgery	Approach	Pathological type
1	Our case	2024	70	M	Displaced	Right	B1	–	S1, S2	14	Right apical segmentectomy	VATS	adenocarcinoma
2	Akamine [8]	2021	72	M	Displaced	Right	B1	–	S1	8	Right apical segmentectomy	VATS	adenocarcinoma
3	Garcia-Reina [14]	2021	32	M	Displaced	Right	B1+B3	–	Right main bronchus	15	Right sleeve postreior segmentectomy	Thoracotomy	Carcinoid
4	Qi [7]	2020	51	F	Displaced	Right	B1+B2	V1 runs dorsal to the PA	S1	14	Right apical segmentectomy	VATS	adenocarcinoma
5	Levin [4]	2018	NA	NA	TRUE	NA	NA	NA	NA	NA	NA	Thoracotomy	SCC
6			NA	NA	Displaced	NA	NA	NA	NA	NA	Right apper lobectomy	NA	SCC
7			NA	NA	TRUE	NA	NA	NA	NA	NA	Right apper lobectomy	NA	SCC
8			NA	NA	Displaced	NA	NA	NA	NA	NA	Apical segmentectomy with tracheoplasty	NA	Carcinoid
9			NA	NA	Supernumerary	NA	NA	NA	NA	NA	Right apper lobectomy	NA	Carcinoid
10			NA	NA	Displaced	NA	NA	NA	NA	NA	Right upper lobectomy	NA	SCC
11			NA	NA	Displaced	NA	NA	NA	NA	NA	Upper sleeve lobectomy	NA	SCC
12			NA	NA	Displaced	NA	NA	NA	NA	NA	Right apper lobectomy	NA	SCC
13	Nakamura [6]	2017	66	F	Displaced	Right	B1	V1-3 runs dorsal to the PA	Right upper lobe	68	Right upper lobectomy	VATS	adenocarcinoma
14	Sumimoto [15]	2016	54	M	Displaced	Right	B1+B3	V1-3 runs dorsal to the PA	Right upper lobe	15	Right upper lobectomy	VATS	adenocarcinoma
15	Xu [16]	2014	39	F	Displaced	Right	B1+B3	Central vein runs dorsal to the PA	S2	8	Right posterior segmentectomy	VATS	adenocarcinoma
16	Sato [17]	2002	61	M	TRUE	Right	B1+B2+B3	NA	Right upper lobe	NA	Right upper lobectomy, Tracheobronchoplasty	Thoracotomy	SCC
17	Okubo [18]	2000	61	M	Displaced	Right	B1+B3	–	B2	15	Right upper sleeve lobectomy	Thoracotomy	SCC
18	Kim [19]	1998	80	M	Displaced	Right	B1	NA	S1	60	Right upper lobectomy	Thoracotomy	adenocarcinoma

Anomalous venous returns are more frequent in cases of tracheal bronchus despite no specific variation. In Additionally, intersegmental veins must be well exposed peripherally when performing a segmentectomy. Therefore, preoperative three-dimensional CT simulation is crucial.

The current case demonstrated no tracheal bronchus-associated issues. Thoracic surgeons should be aware that preoperative planning based on three-dimensional CT is crucial because the presence of tracheal bronchus may be associated with various issues. Good planning contributes to safe segmentectomy in such cases.

Abbreviations

CT

Computed tomography

GGN

Ground-grass nodule

Author contributions

YT drafted the original manuscript. TY and TN reviewed and critically revised the manuscript draft for intellectual content. All authors approved the final version of the manuscript to be published.

Funding

None.

Data availability

Not applicable.

Declarations

Conflict of interest

The authors declare that they have no competing interests.

Ethics approval and consent to participate

The treatment was conducted in accordance with the tenets of the World Medical Association Declaration of Helsinki. The patient provided written informed consent for publication of this case report and all accompanying images.

Consent for publication

Written informed consent was obtained from the patient for the publication of this case report and all accompanying images.