Upper airway obstruction is well described as a cause of apparent asthma, unresponsive to the standard asthma therapy. A careful clinical examination, high index of suspicion, and appropriate analysis of spirometry is essential for the appropriate diagnosis and management.
A 25-year-old woman, previously healthy, presented to the emergency room (ER) with dyspnea. She had smoked cigarettes heavily for the past 10 years. Six weeks prior, she developed a viral upper respiratory tract infection. She was diagnosed with asthma possibly worsened by community-acquired pneumonia and was prescribed antibiotics, salbutamol and fluticasone. The patient did not benefit from this therapy and indeed felt that she had deteriorated.She presented a second time to the ER with worsening dyspnea, where she was found to have a room-air oxygen saturation of 95% and wheezing that was heard throughout all lung fields. Spirometry at that time showed a forced expiratory volume in 1 second (FEV1.0) of 1.6 L (47% predicted) and a forced vital capacity (FVC) of 3.2 L (77% predicted). The ratio of FEV1.0 to FVC was 50%, consistent with the diagnosis of airflow obstruction. She was encouraged to continue bronchodilator therapy and received a prescription for prednisone, and was sent home.She returned the following day with severe dyspnea and was referred for admission because of refractory asthma. Interestingly, inspiratory stridor was recognized on this visit prompting a consult to the otolaryngology service. Spirometry was repeated and considered to be diagnostic of fixed upper airway obstruction. Endoscopy and subsequent computer-assisted tomography (CT) of the neck revealed a subglottic mass approximately 3 cm in diameter. She underwent emergent tracheostomy and examination under anesthesia. A mass inferior to the left vocal cord was biopsied and later diagnosed as small cell cancer of the larynx. Her post-operative course was complicated by bilateral pneumothoraces and aspiration. She was staged as T4N0M0 and referred for chemotherapy and radiotherapy, as the tumour was not resectable. She is in remission with combined cisplatin-based chemotherapy and radiotherapy.DISCUSSION: First observed in Canada in 1972, small cell cancers of the larynx are rare. Only a few case reports are published in the medical literature. These tumors are aggressive, classified under the category of neuroendocrine tumors and are thought to arise from the argyrophilic Kulchitsky cells normally found in laryngeal mucosa. The distinct features on light microscopy suggest the diagnosis that can be confirmed by electron microscopy. The differential diagnoses include carcinoid, atypical carcinoid, small cell squamous carcinoma, small cell ductal carcinoma, lymphoma, mycosis fungoides, and metastatic lung small cell cancer. As with small cell cancers of the lung, they can be associated with ectopic hormone production. The association with smoking has not been definitely proven, as the incidence of this neoplasm is so rare. Systemic chemotherapy with local radiation therapy is the accepted therapeutic approach and may lead to long-term remissions and even cure.CONCLUSIONS: This case illustrates two distinct clinical features. The previous cases of small cell laryngeal cancer have all been described in the middle aged and elderly individuals. Our patient is the only young adult to have developed this malignant neoplasm among all reported cases. Upper airway obstruction is well described as a cause of apparent asthma unresponsive to the standard asthma therapy. A careful clinical examination and analysis of spirometry led to the appropriate diagnosis and management. This case highlights the importance of formulating a comprehensive differential diagnosis and following a systematic, anatomical approach for work up of wheeze.
J. Ronald, None.