Endometrial glandular and stromal breakdown, Part 3: Cytomorphology of “condensed cluster of stromal cells”

A review of the directly sampled endometrial cytology on LBC samples: Classification, microscopic criteria and beyond

The Yokohama System for Reporting Endometrial Cytology (TYS) has been proposed by an expert meeting under the auspices of the International Academy of Cytology (IAC) in May 2016 at the IAC in Yokohama. Since its introduction, the TYS has been receiving worldwide acceptance, and this review aims to assess its global impact. 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 re-evaluate the role of endometrial cytology. LBC is a useful tool in the cytologic diagnosis and follow-up of endometrial abnormalities, which remains complementary to the emerging molecular diagnostic cytopathology. The study of LBC from endometrial cytology could be challenging since it is affected by numerous look-alikes and diagnostic pitfalls. This review discusses these various entities and takes into consideration the ancillary techniques that may be useful in the diagnostic procedure. In conclusion, our review of the published data suggests that the TYS is a valid classification scheme that has been widely accepted by cytopathologists globally, is highly reproducible and makes a valuable contribution to clinical therapeutic management. At present, molecular cytopathology is a rapidly evolving field of modern cytopathology, which underlines the effective interplay between genomics and cytology. This review aims to provide a comprehensive review of the drawbacks of endometrial cytopathology, particularly in terms of endometrial cancer diagnosis and molecular testing.

Staining Pattern of Alcian Blue in Endometrial Cytology: Utility in Distinguishing Grade 1-Endometrial Endometrioid Carcinoma from Endometrial Glandular Stromal Breakdown

Background and Objective

In endometrial cytology, differentiating endometrial glandular stromal breakdown (EGBD) from endometrial endometrioid carcinoma (G1-EEC) is often difficult. In this study, we provided a new focus on chondroitin sulfate (CS), a major substrate component of the endometrial stroma, and assessed the diagnostic utility of Alcian Blue (AB) staining in the differential diagnosis in liquid-based cytological (LBC) samples.

Materials and Methods

LBC specimens from 19 patients with a proliferative endometrium, 36 with EGBD, and 30 with G1-EEC who underwent endometrial cytology were stained with AB (pH 1.0), and their reactivity was observed. In addition, immunocytochemical staining of CS and CD31 was performed for five cases each to evaluate their interrelationship with blood vessels.

Results

Regarding the 30 G1-EEC cases, at least one of the three representative staining patterns was observed by AB staining: dot-like, microtubular, and finely branched linear patterns. Moreover, the inner portion of the tubular material observed by AB staining expressed CD31. Conversely, in the 36 EGBD cases, only five metaplastic clusters with irregular protrusions and condensed stromal clusters (CSCs) showed a dot-like positive pattern, and background CSCs did not show reactivity to AB staining in any of the cases. Furthermore, the vascular structure expressing CD31 in cell clusters was also unclear.

Conclusions

We demonstrated that AB staining shows different staining patterns in G1-EEC and EGBD, reflecting their different tissue structures. Our data provide new insights into endometrial cell diagnosis changes and demonstrate that AB staining is a potential new diagnostic aid tool for the differentiation of G1-EEC from EGBD.

The expression pattern of CD10 and CD31 identifies fine fibrovascular stroma of grade 1-endometrial endometrioid carcinomas in cytology

INTRODUCTION

The objective of this study was to assess the diagnostic utility of CD10 in the differential diagnosis of grade 1-endometrial endometrioid carcinoma (G1-EEC) and the metaplastic changes associated with the endometrial glandular and stromal breakdown (EGBD) on liquid-based cytological (LBC) samples.

METHODS

(1) The type and distribution of CD10-positive cells in EGBD and G1-EEC patients were evaluated. (2) Based on the results from (1), histological and cytological specimens were double-immunostained with CD31 and CD10 to confirm whether CD10-positive tubular-canalicular material found in (1) was represented by fine threads of endometrial-type fibrovascular stroma. (3) Based on the results from (2), additional immunostaining of histological specimens was performed for CD146 and αSMA as markers of perivascular cells.

RESULTS

(1) CD10 positive cells showed two main patterns of expression: cytoplasmic immunoreactivity in the form of dense brown granules in EGBD and tubular-canalicular branching patterns in G1-EEC. (2) The tubular-canalicular material observed in cytological specimens of G1-EEC samples co-expressed CD10 and CD31, and was interpreted as representing fine threads of endometrial fibrovascular stroma in the corresponding histological samples. Conversely, metaplastic changes in EGBD cases, only a few CD31-positive signals were found inside the condensed stromal clusters with CD10-positive. (3) Cells surrounding the CD31-positive vascular endothelial cells expressed CD146 and αSMA; moreover, some of the thin CD10-positive fibrous stromal strands also co-expressed αSMA.

CONCLUSIONS

CD10 is a very useful immunomarker for distinguishing between G1-EEC and the metaplastic changes of EGBD in LBC samples.

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.

Small-cell neuroendocrine carcinoma in directly sampled endometrial cytology: A monocentric retrospective study of six cases

Small-cell neuroendocrine carcinoma (NEC) of the endometrium is extremely rare, and demonstrates an aggressive clinical course. Since reports describing its cytological features are scarce, we aimed to retrospectively analyze these features. Patients with a histopathological diagnosis of NEC who underwent preoperative cytological examination, were enrolled in this study. The cytological features including the background, arrangement, and shape of the neoplastic cells, and the nuclear and cytoplasmic features were reviewed; six patients were enrolled. The conventionally stained, directly sampled cytological specimens showed small neoplastic cell clusters in all cases, as well as isolated neoplastic cells and large clusters in 3 and 2 cases, respectively, in inflammatory or necrotic backgrounds. These neoplastic cells had a high nuclear/cytoplasmic ratio, and round to oval nuclei with powdery chromatin, inconspicuous nucleoli, and scant cytoplasm. Nuclear molding was a characteristic finding. An adenocarcinoma component was also present in 3 cases. Initial cytodiagnosis revealed small-cell NEC and adenocarcinoma or suspected adenocarcinoma in 1 and 4 cases, respectively. The one remaining case was found to be negative and was considered as degenerated endometrial stromal cells. Primarily owing to overlooking this component, the initial cytodiagnostic accuracy of small-cell NEC was low, particularly in cases with coexisting adenocarcinoma. However, the cytological features of this tumor were characteristic. Therefore, although extremely rare, careful observation is essential for an early and accurate diagnosis and to prevent overlooking the small-cell NEC component.

Evaluation of endometrial cytology prepared with the Becton Dickinson SurePath™ method: a pilot study by the Osaki Study Group

OBJECTIVE

To evaluate the sensitivity and specificity of the BD SurePath™ liquid-based Papanicolaou test for assessing the cytology of intrauterine endometrial samples according to newly devised cytological diagnostic criteria and a novel descriptive reporting format.

MATERIALS AND METHODS

One hundred and twenty-two endometrial samples were analyzed. All samples were obtained directly from the intrauterine cavity using the Uterobrush or Honest Super Brush. The samples used for the histological examination and cytological tests were collected simultaneously. Our study group devised new cytological diagnostic criteria for examining endometrial samples: the Osaki Study Group method. In this study, histological diagnosis was considered to be the gold standard for cytological diagnosis. A novel descriptive reporting format was also used.

RESULTS

Satisfactory cytological specimens were obtained in all cases. The sensitivity and specificity of the SurePath endometrial cytological examination method were 96.4 and 100%, respectively.

CONCLUSION

These results indicate that the SurePath method is acceptable for clinical use. Since the SurePath method seems to be easier and allows greater preparation standardization than the conventional method, coupling it with our newly devised cytological diagnostic criteria and descriptive reporting format might represent a reliable diagnostic method for assessing endometrial specimens.

The role of liquid-based preparation in the evaluation of endometrial cytology

OBJECTIVE

Liquid-based preparation (LBP) of the endometrial lesions is an important diagnostic tool for a variety of endometrial abnormalities because of its simplicity and high quali-quantitative diagnostic yield. We aimed to investigate the LBP method for endometrial cytology to evaluate both benign and abnormal endometrial lesions.

STUDY DESIGN

LBP is a semiautomated methodology that has recently become widely available and has gained popularity as a method of collecting and processing both gynecologic and nongynecologic cellular specimens.

RESULTS

Some peculiar endometrial cytoarchitectural features were described using LBPs. These were advantageous to screen as compared to conventional slides due to a smaller screening area and an excellent quality of cell preparations.

CONCLUSIONS

LBP is a useful tool in the cellular diagnosis and follow-up of endometrial abnormalities, which remains complementary to the emerging molecular diagnostic cytopathology. The study of LBPs from endometrial cytology could be challenging since it is affected by numerous look-alikes and diagnostic pitfalls. This review discusses these various entities and takes into consideration the ancillary techniques that may be useful in the diagnostic procedure.

Endometrial glandular and stromal breakdown, Part 4: Cytomorphology of "condensed cluster of stromal cells including a light green body"

This study was undertaken to clarify the origin of the chromophilic substance that stained in light green [light green body (LGB)] was observed in the condensed cluster of stromal cells and in the background of endometrial glandular and stromal breakdown cases. The material consists of cytologic smears of endometrial glandular and stromal breakdown (EGBD) from 58 samples in which a histopathological diagnosis was subsequently obtained by endometrial curettage. The following parameters were examined. (1) The occurrence and number of a LGB. As for the "condensed cluster of stromal cells," "condensed cluster of stromal cells including LGB" and "LBG in background," it was observed with all fields on one slide per case. When it was observed more than one in a preparation, the occurrence was determined and the number was also calculated. (2) Immunostaining of paraffin-embedded tissue sections and cytologic preparations. 1 The occurrence of "condensed cluster of stromal cells," "condensed cluster of stromal cells including LGB" and "LGB in background" was 100%, 44.8% and 91.4%, respectively. The number of "condensed cluster of stromal cells," "condensed cluster of stromal cells including LGB" and "LGB in background" was 21.2, 2.0 and 4.0, respectively. 2 When histological sections from paraffin-embedded tissue were tested by immunocytochemistry, "LGB" stained weakly or negative for fibrinogen, whereas it stained positively for CD31 and factor VIII. In addition, it stained positively for CD42b. 3 When cytologic preparation was tested by immunocytochemistry, "LGB" stained positively for CD31, factor VIII and CD42b. However, as for the fibrinogen, quantitative and qualitative evaluation of the immunocytochemical stain was not feasible due to extensive nonspecific reaction in the whole preparation. The "LGB" in EGBD cases proved to be a thrombus mostly made up by platelets, and it seemed that the recognition of the LGB showed to be a useful cytomorphological criterion for an always more accurate diagnosis of EGBD cases.