Endobronchial metastases in renal cell carcinoma

A 50-year-old man, a reformed smoker, with past history of left nephrectomy for renal cell carcinoma 6 years back, presented to the hospital with fresh complaints of cough for 8 months, loss of appetite and weight. He also complained of coughing out tissue-like material multiple times.

Contrast-enhanced CT scan of the thorax was done which showed intensely enhancing soft tissue density intraluminal branching type masses within the right lower lobe bronchus and its segmental branches, resulting in distal lung collapse and consolidation.

Multiple other intensely enhancing rounded pulmonary nodules of varying sizes were seen in both lungs. Multiple enlarged hyperenhancing mediastinal nodes were seen in subcarinal, lower paratracheal and aortopulmonary window locations.

Visualized upper abdomen showed absence of left kidney, consistent with past history of nephrectomy. Visualized right kidney was unremarkable. No liver or adrenal lesions seen.

Endobronchial lesions can have various causes, most common ones being primary lung malignancy (squamous cell and small cell carcinomas) and neuroendocrine tumours (carcinoid tumour) [1]. Some benign causes of endobronchial lesions include fungal infections, inflammatory pseudopolyp, lipoma and broncholith [2]. Endobronchial metastases (EBM) are very rare accounting for only 1.1% of the endobronchial masses [3].

Lung metastases from extrathoracic malignancies are common, however, endobronchial metastasis is extremely rare. Common sources of EBM include colorectal, renal and breast malignancies [4,5].

Endobronchial metastases need to be differentiated from bronchogenic carcinoma as treatment and prognosis varies. However, clinically, radiologically and on bronchoscopy these two entities are indistinguishable and need histopathological confirmation.

EBM are known to present late in the course of cancer progression with average duration between diagnosis of primary malignancy and detection of EBM being around 50 months [5]. Studies have shown that EBM may not indicate poor prognosis and should not be thought of as a bad prognostic sign in choosing treatment modality [6].

Our patient underwent rigid bronchoscopy and electrosurgical excision of the endobronchial mass. Histopathological analysis showed metastases from clear cell carcinoma. Patient was referred to a higher cancer centre for further management.

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