Atypia in pulmonary cytology: A cytomorphometric analysis of the spectrum of changes between benign and malignant

Grey zones in respiratory cytology: Atypical or suspicious for malignancy and neoplasms of unknown malignant potential

The purpose of pulmonary cytology is two-fold. First, to establish whether a pulmonary nodule is benign or malignant. Second, pulmonary cytology should classify the type of pathologic process present. When a pulmonary nodule is characterized as malignant, it is of high importance to further classify the malignancy as to type, with non-small cell carcinomas being sub-divided into adenocarcinomas, squamous cell carcinomas, and other types of non-small cell carcinoma. The World Health Organization Reporting System for Lung Cytopathology (WHORSLC) provides an important framework for reporting and classifying material obtained by cytologic techniques, including sputum analysis, bronchial brushings, bronchial washings, and fine-needle aspiration. The system contains five categories for specimen reporting. Clinicians prefer definitive diagnoses separating specimens into definitively benign or definitively malignant categories. The WHORSLC recognizes that it is not invariably possible for cytopathologists to separate specimens into definitively benign or definitively malignant categories. The five categories of the WHORSLC recognize the spectrum of cytologic changes running from clearly benign to clearly malignant, which cytopathologists must place into diagnostically useful and reproduceable categories. The intermediate categories of "atypical" and "suspicious for malignancy" provide structured categories with stringent definitions, estimated malignancy risks, and suggested management and follow-up recommendations. In this way, the categories "atypical" and "suspicious for malignancy" aid in maintaining the high diagnostic accuracy of the "benign" and "malignant" categories.

Atypia in pulmonary cytology: Morphologic spectrum and causes

BACKGROUND

The term "atypical" has had a long history of usage in cytology but has had variable definitions and usage. Most commonly the term was used to indicate a degree of cytomorphologic abnormality greater than that clearly due to reactive or reparative changes but not associated with a high concern on the part of the cytopathologist that a malignancy is present. The Papanicolaou Society of Cytopathology System for Reporting Respiratory Cytology provided a foundation for using the category "Atypical" along with the category "Suspicious for Malignancy" to categorize the spectrum of morphologic changes ranging from those which are clearly benign to those that are clearly malignant. The two intermediate categories of "Atypical" and "Suspicious for Malignancy" have characteristic recommendations resulting in clinical utility for both categories.

CONCLUSION

The Papanicolaou Society of Cytopathology System for Reporting Respiratory Cytology represents a useful system with defined intermediate categories of Atypical and Suspicious for Malignancy.