Introduction: Acute dyspnea along with complete opacification of a hemithorax without significant risk factors is extremely concerning in the setting of a healthy young adult. In our clinical encounter, we discuss the need for imaging and bronchoscopy to diagnose and manage primary salivary gland lung tumors. Thorough bronchoscopic evaluation, mediastinal lymph node sampling and complete surgical resection of these endobronchial lesions best predict long-term survival.
Description: An 18 year-old female with a past medical history of mild asthma was admitted to the MICU with dyspnea preceding three days. Chest x-ray showed a complete opacification of the left hemithorax. Subsequent CT chest showed complete obstruction of the left mainstem bronchus leading to significant lung atelectasis. She underwent a rigid bronchoscopy which resected a 1.5 cm lobulated, friable and necrotic endobronchial tumor at the proximal left mainstem bronchus and restored patency of mainstem bronchus. The patient had significant dyspnea relief post-procedure with a pathology report confirming a primary salivary gland-type neoplasm, pleomorphic adenoma. She was safely discharged given clinical improvement, with plans to repeat flexible bronchoscopy in two weeks.
Discussion: Primary salivary gland-type lung cancers are a subset of low-aggressive malignancies with a high tendency to recur and/or metastasize. They tend to occur in younger patients and have a more indolent nature than the common adenocarcinoma and squamous cell lung cancers, and represent less than 1% of all lung cancers. They derive from submucosal exocrine glands in central respiratory tracts with histological subtypes of mucoepidermoid carcinoma (MEC) or adenoid cystic carcinoma (ACC). The prognosis for patients with primary salivary gland-type lung cancer are 5 and 10-year survival rates of 65% and 53%, respectively. Analyzing the patient’s clinical status, radiography, immunoprofile and morphology are crucial to risk stratify this cancer and plan for treatment. Case studies report a general follow-up duration of 4-5 years to assess tumor recurrence, TNM staging, along with obtaining repeat CT and PET to better delineate tumor burden. If the initial pathology report shows low grade tumor burden, surgical resection can lead to favorable long-term outcomes.
