Endobronchial metastasis (EBM) from non pulmonary tumors is uncommon. EBM mimicking bronchial asthma is rare. We report a patient with prior colon cancer presenting with symptoms of bronchial asthma unresponsive to treatment, who was found to have EBM. Her symptoms resolved when EBM responded to radio and chemotherapy.
76 year old non smoking woman without atopy or asthma presented with cough, dyspnea and wheezing of 3 months duration unresponsive to bronchodilators and systemic steroids. Examination revealed wheezing over right chest. Chest radiograph was normal. Her FEV1 was 67% predicted(p) and FEV1/FVC ratio of 69%p without any bronchodilator response and a normal flow volume loop. 5 years ago she underwent right hemicolectomy followed by adjuvant chemotherapy for adenocarcinoma of colon Duke Stage 3. Chest CT and bronchoscopy revealed an endobronchial mass in right bronchus intermedius (figure 1) and a 3mm submucosal nodule on the carina. Biopsy of both lesions showed metastatic colonic adenocarcinoma. Bronchodilators and steroid were discontinued and with external beam radiotherapy and adjuvant chemotherapy her symptoms resolved and no endobronchial tumor was seen on repeat bronchoscopy 2 months later (figure 2). Repeat spirometry was normal. She remains asymptomatic 1 year after her presentation.
Symptoms and signs of airway obstruction may be due to causes other than bronchial asthma. Keys to accurate diagnosis include a consistent history and physical findings of airway obstruction, demonstration of reversible airway disease by spirometry and a favorable response to bronchodilator and steroid treatment. Absence of these key features should prompt further evaluation for other disorders that mimic asthma. Our patient’s past history of colon cancer, localized wheezing, lack of response to asthma treatment and a normal chest radiograph prompted further evaluation for endobronchial disease with chest CT and bronchoscopy. EBM was defined in a recent study as bronchoscopically visible non pulmonary tumors, metastatic to the sub segmental or more proximal central bronchus and with lesions histologically identical to primary tumors previously documented. The incidence of EBM from non pulmonary tumors is estimated to be approximately 2%, but is probably underestimated as endobronchial lesions are seen on bronchoscopy in patient’s with metastatic lung disease in as high as 28-42%. The tumors causing EBM includes breast, colorectal, renal, ovarian, thyroid, uterine, testicular, nasopharynx, prostate and adrenal carcinomas; sarcomas; melanomas and plasmacytomas. The predominant primaries are breast, colorectal and renal carcinomas. The presenting manifestations of EBM are similar to that of centrally located primary bronchogenic carcinoma with cough, hemoptysis, atelectasis and post obstructive pneumonia though in 50-60% the patients are asymptomatic. Dyspnea and wheezing are far less common. Chest radiographic findings may be normal or show atelectasis, nodules, hilar mass and mediastinal adenopathy. Bronchoscopy is diagnostic in these centrally located lesions while chest CT is sensitive in detecting and localizing the lesions. The mean time for the appearance of the EBM can be as long as 5 years (as in our patient) after the diagnosis of primary tumor. Therefore EBM should still be considered in a patient with unexplained respiratory symptoms even though the primary tumor is not recent.Therapeutic approach to EBM is generally radiation and chemotherapy as most patients have extrapulmonary metastases. In some individuals with good performance status, where an EBM represents the sole metastatic site, surgical resection is a viable option. Palliative endobronchial therapies include cryotherapy, brachytherapy, Nd-YAG laser or mechanical resection and stent placement. Mean and median survival of patients with EBM reported is 9 and 15.5 months respectively.
Though uncommon EBM can masquerade as bronchial asthma. In patients with prior history of malignancy, presenting with asthmatic symptoms unresponsive to asthma therapy, EBM should be considered even if the chest radiograph is normal.
Karthikeyan Kanagarajan, None.