MLH1 Methylation Testing as an Integral Component of Universal Endometrial Cancer Screening-A Critical Appraisal

MLH1/PMS2 loss due to MLH1 promoter hypermethylation (MLH1-PHM) is the most common cause of mismatch repair (MMR) deficiency in endometrial cancer (EC). This study aimed to determine the proportion of MLH1-deficient EC with PHM, assess the impact of the reflex MLH1-PHM testing strategy, and evaluate the associated costs within the publicly funded Canadian healthcare system. In a cohort of 2504 EC samples, 534 (21.4%) exhibited dual MLH1/PMS2 loss, prompting MLH1-PHM testing. Among 418 cases with available testing results, 404 (96.7%) were MLH1-hypermethylated, while 14 (3.3%) were non-methylated. The incidence of MLH1 non-methylated cases in our cohort was 14/2504 (0.56%) of all ECs, underscoring the prevalence of hypermethylation-driven MLH1/PMS2 loss in ECs universally screened for MMR deficiency. Reflex MLH1-PHM testing incurs substantial costs and resource utilization. Assay cost is CAD 231.90 per case, amounting to CAD 123,834.60 for 534 cases, with 30 tests needed per additional candidate for MLH1 germline analysis (CAD 6957.00 per candidate). This raises a provocative question: can we assume that the majority of the MLH1-deficient ECs are due to PHM and forgo further testing in healthcare systems with finite resources? It is imperative to assess resource utilization efficiency and explore optimized approaches that encompass clinical correlation, family history and judicious utilization of methylation testing to ensure it is provided only to those who stand to benefit from it.

Primary Vaginal Epithelioid Angiosarcoma: A Case Report and Literature Review of a Rare Neoplasm

Angiosarcoma is a malignant neoplasm showing morphological or immunophenotypic evidence of endothelial differentiation with either a vascular or lymphatic origin. It has a strong predilection for skin and deep soft tissue. Angiosarcomas of the gynecologic tract are very uncommon, and very few cases have been described in medical literature up to this day. Primary vaginal angiosarcomas with no prior history of radiation are exceedingly rare. The epithelioid subtype of primary vaginal angiosarcomas is even more uncommon. Here we present a rare case of an epithelioid subtype of primary vaginal angiosarcoma in a 47-year-old woman with no prior history of radiation who presented with pelvic pain, malodorous vaginal discharge, and a vaginal mass.

Metastatic High-Grade Endometrial Stromal Sarcoma with BCOR Translocation to the Pleural Fluid: A Case Report

Sarcomas in cytology fluids are uncommon, accounting for an estimated 3-6% of malignant effusions. High-grade endometrial stromal sarcomas are uncommon malignancies, whose true frequency is not well defined. We present a case of high-grade endometrial stromal sarcoma with a BCOR translocation metastatic to the pleural fluid. A 31-year-old female with a long-standing history of abnormal uterine bleeding underwent needle core biopsy, which showed a high-grade endometrial stromal sarcoma with a BCOR translocation. In the months following her diagnosis, the patient underwent multiple cycles of chemotherapy along with radiation therapy, but had disease progression. She then presented with bilateral pleural effusions. Cytology from the pleural effusions showed single cells and three-dimensional clusters of spindle-shaped to epithelioid cells. The cell block showed many groups of the atypical cells. The histologic and immunophenotypic features were consistent with metastatic endometrial stromal sarcoma. Ten months after initial diagnosis and two months after positive pleural fluid cytology the patient was deceased. Malignant pleural fluids with sarcoma metastases are not common. Endometrial stromal sarcomas are infrequent malignancies and those with BCOR translocations are recently described with a small number of cases reported. Pleural fluid metastasis of high-grade endometrial stromal sarcoma with BCOR translocation has not, to our knowledge, been described in the literature.

A "Null" Pattern of p16 Immunostaining in Endometrial Serous Carcinoma: An Under-recognized and Important Aberrant Staining Pattern

The ability to distinguish endometrial serous carcinoma (SC) from high-grade endometrioid adenocarcinoma is of great importance given their differences in prognosis and management. In practice, this distinction typically relies upon the use of a focused immunohistochemical panel including p53, p16, and mismatch repair proteins. The expression of p16 is characteristically strong and diffuse in SCs, and weak and/or patchy in many high-grade endometrioid adenocarcinomas. Here, we report a subset of SCs that are entirely negative for p16 immunostaining, a pattern we refer to as "p16 null." This pattern was identified in 2 of 63 cases of SC diagnosed at our institution-1 with histologically classic features and 1 with ambiguous high-grade histologic features. These tumors otherwise showed a SC signature by immunohistochemical and demonstrated an SC pattern of genetic mutations. No mutation in the gene for p16, cyclin-dependent kinase inhibitor 2A (CDKN2A), was identified in either case. However, molecular correlates for the absent p16 expression were present, including homozygous deletion of CDKN2A in one case and hemizygous deletion of CDKN2A with promotor hypermethylation of the remaining allele in the other case. To our knowledge, this constitutes the first report conclusively demonstrating the existence of a small subset of SCs that are completely negative by p16 immunohistochemistry, and the molecular lesions responsible for this pattern. In the context of an otherwise clinically and histologically classic example of SC, we endorse this "null" p16 staining pattern as an alternative aberrant staining pattern that should not deter one from committing to this diagnosis.

Smartphone-assisted tele-gynepathology: A pilot study

INTRODUCTION

Traditional telepathology techniques like whole slide imaging require expensive equipment and are currently out of reach of the developing countries. However, the improvements in smartphone camera resolution and availability of faster internet have made smartphone-assisted telepathology possible.

METHODS

A total of 186 cases pertaining to gynecologic pathology reported by single consultant (NT) were retrieved from the records of the histopathology department. A trained histopathologist then photographed representative areas of each case by using the smartphone camera. After a wash off period of 6 months, the images along with the clinical details were sent by Whatsapp Messenger to the same reporting pathologist. The reporting pathologist replied with the diagnosis of each case by using Whatsapp.

RESULTS

The smartphone diagnosis was concordant in 179/186 (96.2%) cases. The intraobserver concordance rates varied with the organ involved - it was highest for endometrial and myometrial pathology (123/126, 97.6%) lowest for ovarian lesions (08/10, 80%). For cervical pathology, it was 97.2% (35/36) and for fallopian tube pathology it was 92.9% (13/14).

CONCLUSION

Although the initial results of this pilot study are encouraging, there is a long way to go before smartphone-assisted telepathology can be put to routine use for the second opinion. More experience of the pathologists with this technique and faster internet and better smartphone cameras will further improve the concordance of smartphone-assisted telepathology diagnosis with conventional microscopy diagnosis.

How to Handle Lymphadenectomy Specimens to Identify Metastasis More Accurately in Gynecologic Pathology

AIM

To identify the value of processing multiple sections to detect metastasis in lymph nodes (LNs) dissected during gynecologic cancer surgery, and to evaluate the sizes of metastatic LNs in each region to compare with the largest one.

MATERIALS AND METHODS

This retrospective study included 362 patients who had gynecologic cancer with at least one metastatic LN. Slides of 627 metastatic LN specimens were categorized according to the processing technique into single and more than one section (MOS) groups. In the MOS group, the LNs were cut into 2 or 3 parallel slices because their greatest dimensions exceeded 0.5 cm. Sizes of LN metastatic foci (MF) were measured and defined as follows: MF ⩽2 mm as micrometastasis and MF >2 mm as macrometastasis. The largest LN diameters among the metastatic LNs and the largest LNs in those regions were measured. Groups were compared using the Kruskal-Wallis test.

RESULTS

Sixty-five (10.3%) of the metastatic LNs included in this study had micrometastases and 40 (6.3%) of them had MF ⩽1 mm. The rate of micrometastasis was higher in the MOS group than in the single-section group (11.8% vs 8.5%, respectively). Twenty-eight percent (n = 175) of metastatic LNs were not the largest, and 55.5% of those were less than 1 cm in diameter.

CONCLUSION

Methods of LN processing and macroscopic evaluation are not standardized, and processing single sections from LNs may overlook micrometastases. The detection rate of micrometastases can be improved by processing multiple sections from LNs.

Cervical FISH Testing for Triage and Support of Challenging Diagnoses: A Case Study of 2 Patients

PATIENTS

A 29-year-old Caucasian woman (patient 1) and a 23-year-old Caucasian woman (patient 2).Chief Complaints: Abnormal Pap tests with high risk HPV positivity.

HISTORY OF PRESENT ILLNESS

PATIENT 1

In June 2014, this patient was diagnosed with atypical squamous cells of uncertain significance (ASCUS) after a routine screening cervical Papanicolaou (Pap) test. Reflex high risk human papilloma virus (HPV) testing was performed; the results were positive (genotyping was not performed). Subsequent endocervical curettage showed a small focus of immature, atypical squamous cells with abnormally positive p16 staining and an abnormally increased proliferative index staining pattern (evaluated with Ki-67) (Images 1A-1C). These findings strongly suggested a high-grade lesion; nevertheless, due to the minute and focal nature of these findings, a diagnosis was rendered of squamous dysplasia, cannot exclude high grade dysplasia. Additional follow-up was recommended, and the option of a fluorescent in situ hybridization (FISH) assay (HPV-4C, using reagent manufactured by Cancer Genetics Italia S.r.l.) was also suggested as a method of triage to be performed using the same Thinprep collection media used to create the Pap test. The results of the FISH assay were positive, with 6.6% of cells showing gain of the 3q26 region (Image 1D). With this knowledge, the gynecologist performed a cervical loop electrosurgical excision procedure (LEEP), which revealed moderate squamous dysplasia (cervical intraepithelial neoplasia grade 2 [CIN 2]) supported by strong and abnormal p16/Ki-67 co-expression (Images 1E-1G). PATIENT 2: In June 2013, this patient was diagnosed with atypical glandular cells (AGUS) and was shown to have high-risk human papillomavirus (HPV) positivity. (Again, genotyping was not performed.) The subsequent biopsy showed mild reactive atypia of the glandular cells, which did not completely correlate with the atypical cells revealed by the Papanicolaou (Pap) test. Therefore, further follow-up was recommended. A fluorescent in situ hybridization (FISH) assay was performed on the specimen assayed via the AGUS Pap test; the FISH assay yielded positive results, showing many cells with a gain of 3q26 and 5p15 regions above the established cutoff values. A repeat Pap test was performed, which also was interpreted as indicating AGUS. Results of a second HPV-4C FISH assay showed numerous (14.6%) cells with a gain of 3q26 and 5p15 regions (Image 2A). Repeat cervical and endocervical biopsies showed scant atypical glands in otherwise-generous biopsies (Image 2B). Supported by abnormal p16 and Ki-67 immunohistochemical staining results (Image 2C and 2D) and the knowledge of the abnormal FISH assay results, the pathologist diagnosed the patient with endocervical adenocarcinoma in situ (AIS). The results of a subsequent LEEP confirmed the diagnosis of endocervical adenocarcinoma in situ with negative resection margins.

LABORATORY FINDINGS

Abnormal Papanicolaou (Pap) test results with high risk of human papilloma virus (HPV) positivity and scant lesional tissue, as revealed by cervical/endocervical biopsies.