A Rare Case of Endotracheal Metastases in Head and Neck Squamous Cell Carcinoma: A Case Report and Literature Review.

Head and neck squamous cell carcinoma (HNSCC) typically originates from the squamous cells lining the mucosal surfaces of the head and neck. Patients may present with diverse symptoms, including hoarseness of voice, difficulty swallowing (dysphagia), a neck mass, or a cough. While metastasis is usually regional, distant metastases, including tracheobronchial involvement, though rare, can occur and are often associated with a poor prognosis. Here, we report the case of a 64-year-old patient with a history of smoking who presented with complaints of exertional dyspnea and a chronic cough for six months. Pulmonary function tests confirmed a diagnosis of chronic obstructive pulmonary disease (COPD), and bronchodilator therapy with ipratropium was initiated. Four months later, at a follow-up, the patient reported worsening cough and new-onset hoarseness. A CT scan of the neck revealed a lesion on the left vocal cord, and a flexible nasopharyngolaryngoscopy confirmed a left vocal cord tumor. A biopsy and elective tracheostomy were performed, with pathology demonstrating an invasive, moderately differentiated squamous cell carcinoma. A positron emission tomography-computed tomography (PET-CT) scan showed intense fluorodeoxyglucose (FDG) uptake in the vocal cord lesion and bilateral cervical lymph nodes, leading to a diagnosis of stage IV laryngeal cancer (T3N2cM0). The patient underwent concurrent chemotherapy with cisplatin for seven weeks and radiation therapy targeted at the larynx and bilateral neck lymph nodes. A follow-up laryngoscopy and CT scan of the neck, five months post-diagnosis, showed near-complete resolution of the left vocal cord tumor and a reduction in the size of the cervical lymph nodes. Another PET-CT scan, performed six months post-diagnosis, showed no FDG uptake in the left vocal cord and cervical lymph nodes. However, a small focus of FDG uptake was noted in the upper posterolateral aspect of the tracheoesophageal stripe, which was reported as a tracheoesophageal lymph node. An esophagogastroduodenoscopy (EGD) with endoscopic ultrasound (EUS) was planned. However, after a thorough review of PET-CT scan images and discussion at the multidisciplinary team (MDT) meeting, the patient underwent a bronchoscopy instead. This revealed two small endotracheal lesions, confirmed by biopsy as invasive, moderately differentiated keratinizing squamous cell carcinoma. Despite an excellent local response, the patient developed endotracheal metastasis, an uncommon occurrence. This case underscores the complexities in diagnosing head and neck squamous cell carcinoma (HNSCC) with atypical metastatic presentations. It highlights the necessity of an integrated approach for timely diagnosis and expeditious treatment.