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Page 4 of 6 Dharmaraj et al. Mini-invasive Surg 2020;4:65 I http://dx.doi.org/10.20517/2574-1225.2020.51

histopathological diagnosis was solid type adenocarcinoma, T3NO (0/21) MO based on TNM staging, which
translates to Stage IIB disease. The patient was later referred to an oncologist for adjuvant therapy. The
surgical video is available for viewing at https://youtu.be/93xKNmBR4Ns.

DISCUSSION
[1-3]
Tracheal bronchus was first described by Sandifort in 1758 . This condition is also known as bronchial
suis or pig bronchus. It is a rare congenital anomaly, described as an ectolupic bronchus arising from the
lateral wall of the trachea, proximal to the carina. The incidence of tracheal bronchus is reported to be
[1-5]
between 0.1%-3% .

[3,8]
Trachel bronchus more commonly occurs on the right side (0.1%-3%) than the left (0.3%-1%) . Tracheal
bronchus can arise anywhere between the carina and the cricoid cartilage, most commonly 2 cm from the
[9]
carina. The highest origin of tracheal bronchus reported was 6 cm from the carina . Tracheal bronchus
is also associated with other congenital abnormalities like Down’s syndrome, tracheoesophageal fistula,
VATER (vertebra, anus, trachea, esophagus, renal) syndrome, esophageal atresia, laryngeal and duodenal
webs, spinal fusion defects and congenital cardiac defects [3,4,8,9] . Amongst patients with tracheal bronchus,
69% have associated cardiac disease, 35% have associated chromosomal abnormalities and 11% have spinal
fusion defects.

Generally, tracheal bronchus can be classified into displaced and supernumerary types. In the displaced
type, there is a missing segmental bronchus from the right upper lobe bronchus. In the supernumerary
type, the right upper lobe bronchus trifucates into apical, posterior and anterior segmental bronchi [7,9,10] .
The patient in this case report had a displaced tracheal bronchus, as the posterior segmental bronchus
originated from the intermedius bronchus.

Another categorization of tracheal bronchus considers the distance of the tracheal bronchus origin from
the carina. According to this classification, tracheal bronchus is divided into 3 types: (1) Type I: tracheal
bronchus originates more than 2 cm from the carina, with narrowing of the distal trachea; (2) Type II:
tracheal bronchus originates more than 2 cm from the carina, no narrowing of the distal trachea; (3) Type
III: tracheal bronchus originates less than 2 cm above the carina.

Majority of patients with tracheal bronchus are asymptomatic. Symptomatic patients usually present with
recurrent chest infections due to retained secretions. Symptomatic children usually present with stridor
and recurrent pneumonia [1,2,6,8,10] . Treatment is advocated for patients with severe, recurrent symptoms, with
definite treatment being an upper lobectomy. Asymptomatic patients do not require intervention. Despite
being asymptomatic, our patient required intervention due to the incidental mass found on chest X-ray.

Presence of a tracheal bronchus may present a challenge for anesthetists as problems can arise during
intubation. The anomalous bronchus may get occluded by the endotracheal tube, resulting in right
upper lobe collapse and shunting. Accidental intubation of the anomalous bronchus can also lead to
pneumothorax [5,7,10] .

Malignancy arising from a tracheal bronchus is rare. Besides malignancy, there have also been case reports
[7]
on tuberculosis, leiomyoma and massive hemoptysis associated with tracheal bronchus . To date, less than
[11]
20 cases of primary lung malignancy associated with tracheal bronchus have been reported. Uchikov et al.
in Bulgaria was the first to report a case of lung malignancy arising from tracheal bronchus in 1974. The
[12]
second case report in the world was published in 1985 by Moriya et al. , regarding a Japanese patient
with small cell lung cancer which was seen originating from a tracheal bronchus. Due to the rarity of this
pathology, no studies have been performed to investigate the association between a tracheal bronchus and