Bland dyskaryosis: a new pitfall in liquid-based cytology

Objective: To describe our experience in recognizing an unusual presentation of severe dyskaryosis at two large cytology centres using ThinPrep liquid-based cytology (LBC). LBC has been introduced in England following successful pilot studies. It is clear that LBC improves visualization and preservation of cells, and that sensitivity for high-grade dyskaryosis is at least as good as for conventional cytology, and may be better. Several variants of high-grade dyskaryosis have been described on conventional cytology, including small and pale cell dyskaryosis. These are also seen on LBC. We are reporting a new variant of dyskaryosis which in our experience is seen only in LBC specimens prepared by the Thinprep (R) method, which we have named bland dyskaryosis. This has not to our knowledge been previously described. Bland dyskaryosis is characterized by cells with a high nuclear/cytoplasmic ratio, nuclear hyperchromasia and is present in groups with a chaotic architecture. The chromatin pattern appears bland at low power screening examination. On high power examination, however, the chromatin pattern can be seen to be subtly abnormal. Nuclear membranes are smooth. These changes mimic endocervical cells or immature squamous metaplasia at low power. Method: Identification and description of cytological appearances observed in routine practice and correlation with histological diagnosis. Conclusion: The features of bland dyskaryosis should be disseminated through teaching activities. Recognition of this previously undescribed variant will prevent false negative reporting of LBC samples.