Internal quality control in an academic cytopathology laboratory for the introduction of a new reporting system for endometrial cytology

A Diagnostic Approach to Endometrial Cytology by Means of Liquid-Based Preparations

The adoption of endometrial cytology as a diagnostic procedure has been hampered in the past by difficulties arising in interpreting the cellular findings due to a number of factors (such as excess blood, cellular overlapping, and the complex physiology of endometrium). Recently, the use of liquid-based cytology (LBC), with its ability to remove blood and mucus and to distribute cells uniformly in a thin layer on the slide, has provided an opportunity to reevaluate the role of endometrial cytology. LBC samples are easier to screen compared to conventional ones, due to a smaller screening area and an excellent quality of cell preparations. LBC by using peculiar cytoarchitectural features is a useful tool in the cellular diagnosis and follow-up of abnormalities, which, however, remains complementary to histopathology and to the emerging molecular diagnostic cytopathology. This review discusses these various entities and takes into consideration the ancillary techniques that may be useful in the diagnostic procedure. Herein, we also summarize the process and rationale by which updates were made to the standardized terminology in 2018 and outline the contents of the new Bethesda-style classification (the Yokohama system) for the endometrial cytology.

Endometrial Cytology as a Method to Improve the Accuracy of Diagnosis of Endometrial Cancer: Case Report and Meta-Analysis

More and more researchers have reported that dilatation and curettage (D&C) or Pipelle had low accuracy, high misdiagnosis, and insufficient rate. Endometrial cytology is often compared with histology and seems to be an efficient method for the diagnosis of endometrial disorders, especially endometrial cancer. We report a case of misdiagnosed endometrial cancer by D&C, but with a positive cytopathological finding. Following that, a meta-analysis including 4,179 patients of endometrial diseases with cyto-histopathological results was performed to assess the value of the endometrial cytological method in endometrial cancer diagnosis. The pooled sensitivity and specificity of the cytological method in detecting endometrial atypical hyperplasia or cancer was 0.91[95% confidence interval (CI) 0.74-0.97] and 0.96 (95% CI 0.90-0.99), respectively. The pooled positive likelihood ratio and negative likelihood ratio was 25.4 (95% CI 8.1-80.1) and 0.10 (95% CI 0.00-0.30), respectively. The diagnostic odds ratio which was usually used to evaluate the diagnostic test performance reached 260 (95% CI 36-1905). So we recommend that D&C and Pipelle are still practical procedures to evaluate the endometrium, cytological examinations should be utilized as an additional endometrial assessment method.

Evaluation of the benefit and use of the new terminology in endometrial cytology reporting system

OBJECTIVE

The introduction and establishment of a new classification system for endometrial cytology, the "New Terminology in Endometrial Cytology (NTEMC) system," which is based on the Bethesda System for uterine cervical cytology, has recently been reported. However, the clinical management for new categories in the NTEMC system, particularly atypical endometrial cells (ATEC), has not been clarified. The objective of the present study is to determine how the ATEC category should be treated and whether the introduction of the system has decreased the number of unnecessary endometrial biopsies.

METHODS

Fifty-nine cases were diagnosed as "suspicious positive" according to the three-tier reporting (TTR) system, which was adopted in Japan. The specimens were re-evaluated according to the NTEMC system. Thirty-seven of the 59 patients underwent endometrial biopsy. We correlated the pathological diagnosis with the NTEMC system category.

RESULTS

The 59 cases were classified according to the NTEMC system as follows: 36 cases were classified as ATEC of undetermined significance (ATEC-US), 21 cases were classified as ATEC for which atypical endometrial hyperplasia or worse cannot be excluded (ATEC-A), and 2 cases were classified as endometrial hyperplasia. The ratio of atypical endometrial hyperplasia or malignancy in ATEC-US category was significantly lower than that in ATEC-A category. Fifteen cases in ATEC-US category did not show atypical endometrial hyperplasia lesions or malignancy after 3 months.

CONCLUSIONS

These data suggest that patients with ATEC-US results can be followed up for at least three months, and the introduction of the NTEMC system decreased the number of unnecessary endometrial biopsies.