Cytology in Upper Respiratory Tract

Abstract

Respiratory tract cytology is well recognized and widely accepted as the initial step in the diagnosis of respiratory tumors. In particular, bronchial and lung tumors are diagnosed by cytologic examination of either exfoliated cells in sputum or bronchial brush and lavage specimens. Lesions in the upper respiratory tract, including the nasal cavities, mouth, pharynx and larynx, can also be diagnosed using cytology. However, tumors are rare events in the upper airways and relatively few studies have been published [2, 3, 6, 10, 12¡15]. The ¢rst report of cytologic evaluation of exfoliated oral and pharyngeal epithelial cells was published by Beale in 1860. Other authors have since contributed to cytologic examination of the upper respiratory tract. The advantage of cytology is that the collection of cells is simple and usually harmless to the patient and potentially malignant cells, which have lost their cohesiveness to adjacent tissues, are preferentially sampled.Early detection of tumors is crucial for patient survival and false negative results are of particularly great concern. In cervical cytology it is widely acknowledged that up to two thirds of the overall false-negative rates can be attributed to sampling errors. Sampling errors represent a failure to harvest and present diagnostic cells.Nasopharyngeal scrape and brush cytology has been employed to detect both benign and malignant conditions [6,7,10,15].The present article by Merigo and coworkers [7] in this issue of Ultrastructural Pathology presents electron microscopic examination of nasal mucosa from asthmatic children as an ancillary diagnostic method. The specimens were collected by brush cytology and the authors conclude that this minimal invasive test detects mucosal changes that could be related to allergy. Complications related to bronchoscopy were avoided. Granados and coworkers [6] similarly used nasal scrape cytology to diagnose Wegeners granulomatosis, whereas Voss and coworkers [15] identi¢ed precancerous lesions in nasal mucosa of individuals with occupational exposure to nickel and wood. They concluded that brushing and scraping method enables one to collect cells from a larger area than the one sampled by biopsy, thereby yielding more diagnostic material.In two prospective studies by Lau and coworkers [10] and Lundgren and coworkers [12] the diagnostic sensitivity of cytologic examination in diagnosing histologically malignant tumors was 71% and 83%, respectively. Lau et al. used a silk swab stick to diagnose nasopharyngeal carcinomas and Lundgren et al. used a wooden pin and a brush to diagnose laryngeal carcinomas. Adequacy of material, quality of staining and sampling dif¢culties were the major limiting factors, in agreement with Chen and coworkers [2].Fine needle aspiration cytology (FNA) has been shown to be a reliable and safe technique for the diagnosis of malignancy in the head and neck region. The FNA technique is particularly useful in this region because so many disparate entities may be considered in the differential diagnos...