METASTATIC COLORECTAL CANCER PRESENTING AS AN OBSTRUCTING ENDOBRONCHIAL LESION

Abstract

TOPIC: Pulmonary Manifestations of Systemic Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Colorectal cancer is one of the most common malignancies worldwide with the pulmonary parenchyma a common site for distant metastasis. Colorectal endobronchial metastases, however, are exceedingly rare. We present a patient with previously resected colon cancer who was found to have an obstructing endobronchial colorectal metastasis. CASE PRESENTATION: A 66-year-old male with a 12 pack-year smoking history presented with dyspnea. On routine colonoscopy 4 years prior, he was diagnosed with moderately differentiated colorectal adenocarcinoma with negative tumor margins and without any lympho-vascular involvement. Imaging was without evidence of regional or distant metastases so he underwent hemicolectomy. Medical oncology recommended no adjuvant chemotherapy and 1 year follow-up. The patient did not follow-up. Four years later, he presented with fever, dyspnea, cough, and pleuritic chest pain. CT pulmonary angiography demonstrated a RUL mass with RML lobe collapse, a moderate right-sided pleural effusion, and no pulmonary embolism. He was started on empiric antibiotics. Thoracentesis revealed an exudative effusion with negative cultures and cytology. Bronchoscopy demonstrated a fungating endobronchial lesion completely occluding the right middle lobe for which cryobiopsy and cryo-excision were performed. Pathology was consistent with metastatic moderately differentiated colorectal adenocarcinoma, with morphology and histology identical to his prior colorectal cancer. Transbronchial needle aspiration using endobronchial ultrasound of the station 7 mediastinal lymph node was negative for malignant cells. Patient left against medical advice before further work-up was completed. DISCUSSION: About 20% of patients with colorectal cancer have distant metastases at presentation, with the lungs being a common site, usually involving the pulmonary parenchyma and very rarely as an endobronchial lesion. In fact, endobronchial metastases from extra-thoracic malignancies account for 1% of all endobronchial tumors, with the most common being colorectal, breast and renal. These patients may present with a variety of non-specific respiratory symptoms. It is also not uncommon for endobronchial metastasis to occur after resection of the primary tumor and without other signs of metastases. One should consider the possibility of endobronchial involvement of a tumor in a patient with a history of an extra-thoracic malignancy who presents with vague respiratory symptoms, as timely bronchoscopic intervention can improve quality of life and help mitigate the risk of post obstructive complications. CONCLUSIONS: Endobronchial metastasis from extra-thoracic malignancies are very rare, accounting for 1% of all endobronchial tumors. Diagnosis can be difficult due to vague respiratory complaints. Bronchoscopic intervention can assist in diagnosis, management, and it can lead to substantial improvement in pulmonary symptoms. REFERENCE #1: Akoglu S, Uçan ES, Celik G, et al. Endobronchial metastases from extrathoracic malignancies. Clin Exp Metastasis. 2005;22:587–591. REFERENCE #2: Coriat R, Diaz O, de la Fouchardiere C, et al. Endobronchial metastases from colorectal adenocarcinomas: clinical and endoscopic characteristics and patient prognosis. Oncology. 2007;73:395-400. REFERENCE #3: Lin CY, Chung FT. Central airway tumors: interventional bronchoscopy in diagnosis and management. J Thoracic Dis. 2016;8(10):E1168-E1176. DISCLOSURES: Speaker/Speaker's Bureau relationship with Boehringer-Ingelheim Pharmaceuticals Please note: $5001 - $20000 by Jaime Betancourt, source=Web Response, value=Honoraria Speaker/Speaker's Bureau relationship with Vapotherm, Inc Please note: $5001 - $20000 by Jaime Betancourt, source=Web Response, value=Honoraria Speaker/Speaker's Bureau relationship with Boehringer-Ingelheim Pharmaceuticals Please note: 2014-Present Added 04/21/2021 by Jaime Betancourt, source=Web Response, value=Honoraria Speaker/Speaker's Bureau relationship with Vapotherm, Inc Please note: 2019-Present Added 04/21/2021 by Jaime Betancourt, source=Web Response, value=Honoraria Advisory Committee Member relationship with Vapotherm, Inc Please note: 2020 Added 04/21/2021 by Jaime Betancourt, source=Web Response, value=Honoraria No relevant relationships by Ken Dekitani, source=Web Response No relevant relationships by Michael Lewis, source=Web Response No relevant relationships by Roberto Mempin, source=Web Response No relevant relationships by Scott Oh, source=Web Response