Classic cytological appearances of high-grade intraepithelial lesions are frequently not encountered in routine practice and there are many mimics of benign and neoplastic changes that may lead to errors in diagnosis. Pitfalls in cervical cytology may conveniently be divided into three categories:
- Potential false negatives
- Potential false positives
- Unnecessary atypical/borderline reports
The aim of this chapter is to alert primary screeners and pathologists to types of changes that are well recognised as potential problems that can be avoided if known about.
- This chapter links to examples of cytology pitfalls seen in clinical practice that have been scanned as whole slides on the Eurocytology wesbsite
- This chapter also links to Chapter 12 in which cytology is placed in the context of colposcopy, histology and ancillary tests.
- This chapter also links to a slide seminar of 15 difficult cases that were used for the BSCC Terminology Conference in 2002, which informed the revised UK terminology (Denton et al. 2008).
- The BSCC slide seminar should be examined before reading the present chapter, which gives correct answers of some of the cases.
- Typical features of normal cytology, reactive changes, LSIL, HSIL, glandular abnormalities and cancer are illustrated in Chapter 9.
- False positives, false negatives and unnecessary atypical/borderline reports can be avoided by adequate training, regular update, quality control and multidisciplinary discussion of atypical cases.
Features of dyskaryosis
- Abnormal chromatin pattern unevenly distributed within the nucleus (irregularly irregular)
- Chromatin pattern varies from finely speckled or punctate to coarsely clumped and densely hyperchromatic
- Mitoses are usually absent or inconspicuous
- The nuclear membrane is irregular with protrusions or indentations
- Dyskaryosis is present in all grades of CIN or SIL