We report an unusual case of partial airway obstruction resulting from distant metastasis of a clear cell carcinoma of the kidney. This patient had no prior diagnosis of cancer before the tracheal mass was endoscopically resected using a holmium:YAG laser, and post-resection work-up revealed the primary kidney tumor.
A healthy 54-year-old man developed a persistent cough, progressive shortness of breath and paroxysmal nocturnal dyspnea. He was treated for new onset asthma, but his symptoms persisted. Despite a normal chest x-ray, chest computed tomography (CT) demonstrated a 15-20mm polypoid lesion in the distal trachea. Intra-operative flexible bronchoscopy revealed a white, firm lesion in the distal trachea with partial airway obstruction. The 1.5 x 1.0 cm mass was densely adherent to the tracheal wall, and was endoscopically excised using a holmium:YAG laser. His symptoms improved considerably. Pathologic diagnosis demonstrated metastatic renal clear cell carcinoma. Work-up demonstrated a 3.5 x 5.6 cm mass in the right kidney by CT. The patient had a left nephrectomy as a child secondary to chronic infections. Therefore, an attempt was made to spare as much normal kidney as possible, and he underwent a complex right partial nephrectomy. Pathology confirmed multifocal renal cell carcinoma, clear cell type, nuclear grade 2. Six weeks following resection, he developed rib and lung lesions. He was treated with high-dose Interleukin-2, and is being followed closely.
Metastatic tumors to the tracheobronchial tree are highly unusual, and occur in 2% of patients with solid tumors . Most patients with tracheobronchial metastases have a primary diagnosis of cancer prior to identifying the metastases. Tumors of the breast, colon, rectum, pancreas, kidney, thyroid, and skin have been shown to metastasize to the tracheobronchial tree [2,3]. These tumors are often diagnosed late in the course of the disease because of the delayed onset of specific symptoms. The large diameter of the trachea, relative to the bronchi, allows tracheal tumors to grow to large sizes before symptoms can become significant. In contrast to lung parenchymal metastases, the significantly lower number of reported tracheal metastases is thought to be secondary to a difference in blood supply. The lung parenchyma is supplied by the pulmonary artery, through which all systemic blood passes, while the trachea is supplied by the bronchial artery. The bronchial artery receives only a small portion of the systemic circulation. Thus, hematogenous spread is more likely to favor the lung parenchyma. Commonly, metastatic lesions to the tracheobronchial tree are located distal to the carina and cause atelectasis in the affected segmental lung field. Plain chest radiographs can often demonstrate these lesions, but CT is also helpful for making the diagnosis. Laser bronchoscopy and resection have become increasingly useful in excising the tumor and in obtaining a tissue diagnosis.
There are few reported cases in the literature of metastatic tumors to the trachea, and none of these have involved finding the metastatic lesion in a patient without a prior diagnosis of cancer. Laser bronchoscopy is an effective and straightforward treatment method. Control of the primary tumor needs to be aggressively pursued while addressing the tracheobronchial metastasis.
G.H. Wheatley, None.