Endobronchial Metastases after Radical Resection of a Primary Lung Cancer.

Endotracheal/endobronchial metastasis (EEM) generally originates from nonpulmonary malignancies such as cancers of the breast, colon, and kidney. Although the incidence of EEM has been reported to be between 2.0% and 50.0%, cases diagnosed after radical resection of primary lung cancer are extremely rare.[12] We hereby presented a patient of squamous cell lung carcinoma who was confirmed to have EEM 3 years after his radical resection of primary tumor.

A 46-year-old male smoker was admitted on July 20, 2011, because of repeated nonproductive cough and blood-tinged sputum for approximately one month. The chest computed tomography (CT) scan showed a right hilar nodule of <2.0 cm in diameter which partially occluded the right upper lobe bronchus with local atelectasis [Figure 1a]. Mass at the orifice of the right upper bronchus was detected by bronchoscopy while no other lesion was observed in the mucosa of tracheal and bronchial. Pathologic analysis of the specimen suggested a malignant suspected neoplasm. A right upper sleeve lobectomy and systemic lymph node dissection was performed and a mass of 1.8 cm × 1.0 cm × 0.8 cm was excised. The tumor was further proved by histopathology to be a primary moderate differentiate squamous cell lung carcinoma which positively expressed markers of P63, P40, and cytokeratin (CK) 5/6. Four out of 32 peribronchial lymph nodes were positive for metastasis analysis whereas the bronchial margins were negative which confined the stage to be pT1aN1M0 (Stage IIa). Thus, chemotherapy was applied. During the 36-month postoperative follow-up, the patient was asymptomatic with negative chest CT screening [Figure 1b]. However, the last bronchoscopy examination conducted 3 years after his radical resection of primary lung cancer revealed multiple tiny nodules of approximately 0.1 cm in diameter in the left main bronchus. These lesions were further characterized to be squamous cell carcinoma which had identical pathologic features as the primary resected tumor [Figure 1c and 1d]. Therefore, the patient received sequential treatment of transbronchial argon knife therapy, endotracheal radiotherapy, and chemotherapy for conservative treatments until no lesion of tiny nodules could be detected by bronchoscopy [Figure 1e]. The patient was still alive after 14-month follow-up.

Figure 1

Endobronchial metastases after radical resection of a primary lung cancer. (a) Preoperative chest computed tomography scan showed a right hilar nodule of <2.0 cm in diameter (arrow); (b) Postoperative 36-month chest computed tomography scan was negative (arrow); (c) Bronchoscopy presented multiple very tiny nodules located in the left main bronchus (arrow); (d) Histology showed moderately differentiated squamous cell carcinoma (arrow) expressing P63, P40 within the nucleus and cytokeratin 5/6 in the cytoplasm by immunohistochemistry, identical to previously resected primary lung cancer (Hematoxylin-eosin, original magnification ×100); (e) Transbronchial argon knife therapy was performed (arrow).

EEM is defined as bronchoscopically visible pulmonary tumors located in the subsegmental or more proximal central bronchi which have identical histopathology characteristics comparing to the primary tumor. To the best of our knowledge, very few cases of EEM which happed after the radical resection of primary lung cancer have been reported.[134] Metachronous recurrence usually develops at least several months after the resection of the primary site, while synchronous recurrence develops with the primary tumor.[12] The interval time of metachronous recurrence has been reported to be 8–52 months (mean, 25.8 months) and the incidence is about 0.4%.[3]

The symptoms associated with EEM are similar to those with primary endotracheal/endobronchial tumor regardless of its primary site. It has been reported that hemoptysis with coughing is the most common symptom, with an incidence of 41.0–62.0%, while dyspnea and wheezing occurring are less often. Still, about 26.0–62.5% of the patients can be totally asymptomatic.[3]

Postoperative follow-up, chest CT scan might detect the main lesions of EEM which can be presented as nodules or wall thickness of trachea and bronchus. The bronchoscopy is a valuable tool for detection of EEM as the CT scan may give false negative results, which is just the case of the patient presented in this report.[34] The main aim of performing bronchoscopy was to exclude postoperative recurrence of local bronchial anastomosis because he underwent a right upper sleeve lobectomy with central lung cancer in the right upper lobe and chemotherapy was applied due to pathology Stage IIa 3 years ago. The diagnosis is usually rely on the histology and immunohistochemistry and sometimes also by gene mutation analysis of epidermal growth factor receptor (EGFR), Kirsten Ras (KRAS), and anaplastic lymphoma kinase (ALK).[1] The histology usually revealed all tracheal tumor cells were involved the submucosal layer and some were found within the submucosal lymphatic vessels presenting as tumor emboli, so cause of EEM was thought that tracheal tumor cells might originate from the primary site through submucosal lymphatic or blood vessels rather than from carcinoma in situ.[3]

The setup of treatment should take several factors into consideration, including the histopathological feature and biological behavior of the primary tumor, the anatomic location of the primary as well as the metastatic lesions, and the general status of the patients. The final clinical management strategy can be highly individualized.[34] Surgical excision, local radiotherapy, and transbronchial endoscopic procedures might all be part of the therapy. The effective palliative treatments are brachytherapy, photodynamic therapy, and laser ablation. The patient underwent transbronchial argon knife therapy (ERBE Elektromedizin GmbH, Tuebingen, Germany) and endotracheal radiotherapy and the reasonable result was achieved. Although EEM is generally a manifestation of a far-advanced disease stage which indicates poor prognosis, the outcome of the patients might still depend largely on the biological behavior of the particular tumor and its responsiveness to the treatments.[3]

In summary, we presented a case of endobronchial metastases after radical resection of a primary squamous cell lung carcinoma. The experience suggests that bronchoscopy is of great value in detecting insidious EEM lesions and palliative treatment could be performed after the diagnosis of EEM.

Financial support and sponsorship

This study was supported by a grant from Zhejiang Province Traditional Chinese Medicine Scientific Research Fund (No. 2011ZB012).

Conflicts of interest

There are no conflicts of interest.