Inflammation
The cytologic features of common inflammatory processes, such as organizing pneumonia, bronchiolitis obliterans obstructing pneumonia and diffuse alveolar damage, are considerably overlapping. Inflammatory cells are observed, such as macrophages, neutrophils, eosinophils and lymphocytes. Reactive pneumocytes are especially common in organizing pneumonia and diffuse alveolar damage. The lung is the most common site of sarcoidosis, which […]
Respiratory infections
Cytology plays an important role in diagnosing infectious diseases in immunocompromised patients. Conventional inflammatory response may be much reduced, absent or greatly altered in these patients. Viral infections Bacterial infections Fungal infections Pneumocystis carinii Echinococcosis (hydatid disease)
Bacterial infections
Bacterial infections present as pneumonias or abscesses. Acute pneumonia and lung abscesses are characterized by a neutrophilic exudate. Many bacteria, but not all, can be seen with Routine stains as well as with Gram stain. A specific identification of Legionella pneumophila can be made in BAL samples by immunofluorescent antibody staining. Infection by Mycobacterium tuberculosis […]
Preneoplastic changes of respiratory epithelium
Squamous cell carcinoma of the lung is preceded by precursor lesions, with a progression from benign squamous metaplasia, through dysplasia, to invasive cancer. Most authors acknowledge degrees (mild, moderate, severe) of dysplasia. The risk of developing bronchogenic carcinoma increases with the degree of atypia. Preinvasive lesions Squamous dysplasia Carcinoma in situ Atypical adenomatous hyperplasia Diffuse […]
Liquid-based cytology (LBC)
Liquid-based cytology (LBC) has emerged as an alternative to conventional cytopreparatory methods. In particular, LBC has been extensively implemented in the cervical screening program, but it has found broader acceptance also in non-gynecologic cytologic preparations. LBC uses a specially devised instrument which allows a monolayer of cells to be obtained from a liquid sample. Most studies […]
Respiratory Tract
On completion of this section the cytotechnologist should Know: the anatomy and histology of the respiratory tract the role and indications of respiratory tract cytology the advantages and disadvantages of the different sampling methods the reporting terminology cytologic features of normal cells from the respiratory tract the non-cellular elements and contaminants which may appear in […]
Anatomy and histology of the respiratory tract
The respiratory tract can be divided into upper and lower compartments. The upper airway extends from the sino-nasal area to the larinx. The lower tract extends from trachea to the lungs and is the major focus of respiratory cytology. Cells of the upper airway are occasionally observed in the specimens from the lower tract. The […]
Indications of respiratory tract cytology
Compared with the remarkable success of the Pap smear in detecting and preventing cervical cancer, respiratory cytology (mostly sputum) has been a disappointment as a mass screening test for lung cancer. The problem is not lack of accuracy (sensitivity or specificity), but rather that even in high-risk patients (such as male smokers older than 45 […]
Cell sampling and preparation methods
Respiratory cytomorphology is heavily dependent on specimen type and preparation. Cell sampling and preparation methods are crucial for a correct cytologic interpretation. In the diagnosis of pulmonary nodules, bronchoscopic methods are usually the first approach for central lesions; if negative, fine needle aspiration (FNA) cytology can be performed. FNA cytology is particularly useful for peripheral […]
Sputum
Sputum consists of a mixture of cellular and non-cellular elements cleared by mucociliar apparatus. It is easy to obtain and cause little or no patient discomfort, but its use is declining because of the advent of bronchoscopy and fine needle aspiration. The sensitivity of sputum cytology for the diagnosis of malignancy increases with the number […]