High-Grade Uterine Sarcoma: First Report of a MEIS2::FOXO4 Fusion.

Uterine sarcomas are uncommon mesenchymal neoplasms ranging from low- to high-grade or undifferentiated. High-grade sarcomas are characterized by various morphologic, immunohistochemical, and molecular alterations. Here, we report the first description of a patient with uterine sarcoma with a MEIS2::FOXO4 fusion.

Comparison of HER2 Scoring Systems in Endometrial Cancer: Toward Optimization of HER2-Directed Therapies.

Endometrial carcinomas (EC) show variable HER2 protein expression or gene amplification and may be eligible for HER2-directed therapy (trastuzumab or antibody-drug conjugates (ADCs) such as trastuzumab-deruxtecan). HER2 testing is currently recommended in advanced-stage/recurrent serous carcinomas and carcinosarcomas. However, no universally adopted reporting guidelines exist, and institutional practices vary.

Vulvar Cellular Angiofibroma With Cytologic Atypia and Sarcomatous Transformation: A Clinicopathologic Analysis.

Cellular angiofibromas (CAFs) are benign mesenchymal neoplasms of the vulva and lower genitourinary tract. Although most cases are benign with excellent prognosis, data on CAFs with cytologic atypia (aCAF) and sarcomatous transformation (tCAF) is limited. We identified 13 vulvar CAFs comprising 4 aCAFs and 9 tCAFs.

Cervical Human Papillomavirus-Independent Squamous Cell Carcinoma: A Clinicopathological Review and Outcomes Analysis Compared With Human Papillomavirus-Associated Squamous Cell Carcinoma.

Human papillomavirus (HPV)-independent cervical squamous cell carcinomas (HPVI SCCs) represent a poorly characterized entity. We aimed to explore the clinicopathological and survival features in the largest series of HPVI SCCs and compare them to HPV-associated (HPVA) SCCs. Eighty-nine cases of SCC previously tested negative for high-risk and low-risk HPV were collected from 22 institutions.

Malignant Brenner Tumor of the Ovary: A Critical Reappraisal.

Malignant Brenner tumors (MBTs) are rare epithelial tumors of the ovary, most likely arising from benign and borderline Brenner tumors. MBTs may be misdiagnosed as other primary carcinomas or nonepithelial tumors of the ovary as well as metastatic carcinomas. Accurate diagnosis usually requires clinical-radiologic correlation, extensive sampling, and immunohistochemical studies.

Presence and extent of lymphovascular invasion in surgical stage I squamous cell carcinoma of the cervix: a comprehensive, international, multicentre, retrospective clinicopathological study.

The aim of this study was to determine whether the presence and extent of lymphovascular invasion (LVI) is prognostic in surgical stage I cervical squamous cell carcinoma (SCC). All available tumour slides and/or paraffin blocks from 426 patients with stage I cervical SCC treated surgically with curative intent were collected from 18 institutions and retrospectively analysed. Presence and extent of LVI (focal <5 spaces, extensive ≥5 spaces) were assessed on scanning magnification in large haematoxylin and eosin slide sets in 366 cases.

Validation Study of the Newly Proposed Refined Diagnostic Criteria for Malignant Phyllodes Tumor With 136 Borderline and Malignant Phyllodes Tumor Cases.

The World Health Organization (WHO) diagnostic criteria for malignant phyllodes tumor (MPT) may miss a significant number of MPTs with metastatic potential. New refined diagnostic criteria (Refined Criteria) for MPT were recently proposed. The aim of this study is to validate the Refined Criteria.

The Malignant Potential of Ovarian Steroid Cell Tumors Revisited: A Multi-institutional Clinicopathologic Analysis of 115 Cases.

Steroid cell tumors (SCTs) of the ovary are rare and understudied, and as such, uncertainties remain about their malignant potential, as well as clinicopathologic predictors of patient outcome. Based on a multi-institutional cohort of cases, we present findings from the largest study of SCT reported to date. Clinicopathologic data were documented on 115 cases of SCT that were assembled from 17 institutions.

Identification of Glandular (Acinar)/Tubule Formation in Invasive Carcinoma of the Breast: A Study to Determine Concordance Using the World Health Organization Definition.

Context.—: The Nottingham Grading System (NGS) developed by Elston and Ellis is used to grade invasive breast cancer (IBC). Glandular (acinar)/tubule formation is a component of NGS.

Subspecialized breast pathologists have suboptimal interobserver agreement in Ki-67 evaluation using 20% as the cutoff.

Purpose: Ki-67 expression levels in breast cancer have prognostic and predictive significance. Therefore, accurate Ki-67 evaluation is important for optimal patient care. Although an algorithm developed by the International Ki-67 in Breast Cancer Working Group (IKWG) improves interobserver variability, it is tedious and time-consuming.

Sarcomas With RAD51B Fusions Are Associated With a Heterogeneous Phenotype.

RAD51B-rearranged sarcomas are rare neoplasms that exhibit a heterogeneous morphology. To date, 6 cases have been reported, all involving the uterus, including 4 perivascular epithelioid cell tumors (PEComas) and 2 leiomyosarcomas (LMS). In this study, we describe the morphologic, immunohistochemical, and molecular features of 8 additional sarcomas with RAD51B rearrangement, including the first extrauterine example.

Teratoma-associated and so-called pure Wilms tumour of the ovary represent two separate tumour types with distinct molecular features.

Aims: Ovarian Wilms tumour (WT)/nephroblastoma is an extremely rare neoplasm that has been reported to occur in pure form or as a component of a teratomatous neoplasm. We hypothesized that teratoma-associated and pure ovarian WT may represent different tumour types with diverging molecular backgrounds. To test this hypothesis, we comprehensively characterized a series of five tumours originally diagnosed as ovarian WT.

Targeted RNA Sequencing Highlights a Diverse Genomic and Morphologic Landscape in Low-grade Endometrial Stromal Sarcoma, Including Novel Fusion Genes.

Low-grade endometrial stromal sarcoma (LGESS) represents a morphologically and genetically heterogenous mesenchymal neoplasm. Previous work has shown that approximately half of LGESS are characterized by JAZF1::SUZ12 gene fusions, while a smaller proportion involves rearrangement of other genes. However, a subset of cases has no known genetic abnormalities.

Intraoperative assessment of axillary sentinel lymph nodes by telepathology.

Purpose: Although axillary dissection is no longer indicated for many breast cancer patients with 1-2 positive axillary sentinel lymph nodes (ASLN), intraoperative ASLN assessment is still performed in many institutions for patients undergoing mastectomy or neoadjuvant therapy. With recent advancements in digital pathology, pathologists increasingly evaluate ASLN via remote telepathology. We aimed to compare the performance characteristics of remote telepathology and conventional on-site intraoperative ASLN assessment.

Mammary Spindle Cell Proliferations on Core Needle Biopsy: Is Excision Always Necessary?

Mammary spindle cell proliferations (SCPs) encompass a wide range of lesions and can be challenging to accurately diagnose on core needle biopsies (CNBs). Most SCPs are excised for definitive diagnosis. In the era of minimally invasive therapy, some SCP may be followed conservatively.

Inflammatory Lesions of the Breast.

Context.—: Inflammatory lesions of the breast are rare but not infrequently pose problems both clinically and morphologically, particularly on needle core biopsies. These lesions range from acute inflammatory conditions to chronic lymphoplasmacytic and lymphohistiocytic to granulomatous inflammatory diseases.