Virchows Archiv最新文献

HER2-low and -ultralow breast cancer have recently emerged as distinct theranostic subcategories within the HER2 spectrum, prompting reassessment of traditional HER2-negative immunohistochemistry scores (0, 1+ , and 2+ without amplification). This study reclassifies, according to this new categorization, a cohort of 367 patients who have never received chemotherapy and have non-metastatic triple-negative breast cancer (TNBC). We evaluated its association with their clinicopathological features and prognosis. HER2 0 tumors were reclassified as HER2-null (no staining) or HER2-ultralow (≤10% faint, incomplete membrane staining). HER2 1+ or 2+ (non-amplified) tumors were defined as HER2-low. Overall, 38.4%, 37.6% and 24.0% of TNBC samples were reclassified as HER2-null, -ultralow and -low, respectively. HER2-ultralow tumors were more frequently associated with the presence of tertiary lymphoid structures (p = 0.0259) and BRCA1 promoter methylation (p = 0.0439) than HER2-low tumors. Moreover, compared with HER2-null samples, HER2-ultralow tumors were of smaller size (p = 0.0167) and lower stage and grade (p = 0.0066 and p = 0.0364, respectively). Conversely, age, lymph node involvement, histology, molecular apocrine or basal-like phenotypes, PIK3CA and PTEN status, immune infiltrates, assessed using T-cell (CD3), B-cell (CD20) and macrophage (CD163) markers, and PD-L1 expression in tumor or stromal cells were not associated with the HER2-ultralow status. The survival analysis (median follow-up = 10.3 years) showed that relapse-free survival was not influenced by the HER2 status. Despite some significantly different clinicopathological features, there is no solid evidence to support HER2-ultralow, HER2-low and HER2-null cancers as individual TNBC clinical-molecular entities. Particularly, assigning TNBC samples to the HER2-null, -ultralow and -low categories did not bring any additional prognostic value.

The reliable diagnosis of one of the many types of B-cell lymphoma (BCL) currently requires an integrated approach comprising morphological expertise, immunophenotyping, and inclusion of clinical data, but may also incorporate flow cytometry, cytogenetics, and clonality analysis. In recent years, several studies have elucidated the mutational landscape of BCL, which may also serve as a complementary diagnostic tool. We have developed a custom next-generation sequencing panel for application in the routine diagnosis of BCL based on available literature and our diagnostic questions. We applied this panel to 160 cases of BCL or with this differential diagnosis (DD) in our routine workflow to gain further diagnostic support or on clinical request. Evaluable results were obtained in all but two cases of the entire cohort. Diagnostically informative molecular genetic profiles were identified in 72% of the evaluable cases. Focusing on 21 challenging cases with the DD of Burkitt lymphoma (BL) and the germinal center B-cell-like subtype of diffuse large B-cell lymphoma (DLBCL), we detected at least one mutation in all cases, and in 18/21 (86%) cases, panel sequencing provided significant decision guidance. In conclusion, although morphology and immunohistochemistry remain the backbone of diagnosis, panel sequencing provided substantial diagnostic assistance in many cases. It has been particularly useful in providing additional arguments to clarify the clinically important DD between BL and DLBCL in challenging cases.

Proliferative verrucous leukoplakia (PVL) is a rare yet aggressive oral potentially malignant disease (OPMD) with the greatest rate of malignant transformation. Its pathophysiology is poorly understood despite much histopathological and molecular research. Particularly, Telomerase reverse transcriptase (TERT) promoter mutations at C228T and C250T have been linked to many epithelial malignancies; however, their significance in PVL is yet unknown in the Indian population. The aim of this study was to assess frequency of TERT promoter mutations (C228T, C250T) and rs2853669 single nucleotide polymorphism (SNP) in PVL, oral leukoplakia (OL), oral squamous cell carcinoma (OSCC) and healthy controls. 120 fresh frozen tissue specimens (30 each of OL, PVL, OSCC and controls) were tested for presence of C228T and C250T mutation in TERT promoter gene region and SNP at rs2853669, using Sanger sequencing on genomic DNA. TERT C228T mutation was found in 6.7%, 0% and 20% cases in PVL, OL and OSCC group (p = 0.03) respectively. TERT C250T mutation was present only in OSCC group (6.7% cases). None of the two mutations were present in controls. Both the mutations were mutually exclusive of each other. A significant association was found between rs2853669 SNP and epithelial dysplasia in OL, specifically with CC genotype (p = 0.04). Molecular signature of PVL shows limited evidence of TERT promoter mutations. The findings of this study suggest that the genetic underpinnings of PVL are distinct from those commonly observed in other forms of cancerous lesions.

We report a case of GALT-associated carcinoma, a rare morphological variant of colorectal adenocarcinoma characterised by cystic glands containing eosinophilic material, set within dense lymphoid stroma with germinal centres. Since its first description in 1999, only 26 cases have been documented. Its association with lymphoid tissue, the presence of intraepithelial lymphocytes, and the absence of goblet cells led to the hypothesis that it may originate from M-cells located in the dome epithelium of gut-associated lymphoid tissue, hence the alternative term "dome-type carcinoma". Through detailed histological, immunohistochemical, ultrastructural and molecular analyses of our case, supported by a comprehensive literature review, we found no evidence supporting M-cell differentiation: intraepithelial B lymphocytes were absent, GP2 immunostaining was negative and ultrastructural features were inconsistent with M-cell morphology. Nevertheless, the lesion's pushing growth pattern, lack of high-risk histopathological features and indolent behaviour justify its recognition as a distinct morphological subtype of colorectal cancer.

Epithelioid leiomyosarcoma (ELMS) of the uterus is an uncommon and diagnostically challenging variant of leiomyosarcoma. We report, to our knowledge, the first ELMS harboring an HMGA2::RAD51B fusion and delineate its clinicopathologic and molecular features. A 64-year-old woman underwent total hysterectomy with bilateral salpingo-oophorectomy for a large myometrial mass initially favored as endometrial stromal sarcoma. Histology showed a multinodular, infiltrative tumor composed of epithelioid cells in trabecular and solid nests within hyalinized stroma, with moderate atypia and brisk mitotic activity (up to 14/10 high-power fields; ~ 6 mitoses/mm²). Infarct-type necrosis was present without unequivocal tumor cell necrosis. Immunohistochemistry supported smooth-muscle differentiation (alpha-smooth muscle actin diffuse; desmin focal; h-caldesmon rare) with estrogen receptor and HMGA2 positivity and negativity for melanocytic markers (HMB45 and Melan-A). RNA-based targeted sequencing (Archer FusionPlex Sarcoma) detected a high-confidence, in-frame HMGA2 (exon 3)::RAD51B (exon 11) fusion. The integrated morphologic, immunophenotypic, and molecular profile excluded endometrial stromal sarcoma with smooth-muscle differentiation, perivascular epithelioid cell tumor, and uterine tumor resembling ovarian sex-cord tumor, establishing ELMS. The patient remains disease-free at 4 months. This case expands the molecular spectrum of ELMS and, concomitantly, broadens the emerging morphologic spectrum of RAD51B-rearranged uterine sarcomas, underscoring the diagnostic value of fusion testing in unusual uterine mesenchymal neoplasms.

The promising efficacy of novel anti-HER2 antibody-drug conjugates in breast cancer has led to the recognition of HER2-low and HER2-ultra-low in advanced solid tumors, including salivary gland carcinomas. In this study, we explore the frequency of HER2-low and HER2-ultra-low immunoexpression in a retrospective cohort of 81 salivary gland carcinomas, including 35 salivary duct carcinomas (SDC) and 46 non-SDCs. HER2 immunohistochemistry was interpreted according to ASCO/CAP guidelines. Among SDCs, the frequency of HER2-positive (3 +), HER2-low (1 + and 2 +), and HER2-ultra-low (0 +) was 34%, 63%, and 0%, respectively. None of the non-SDCs was HER2-positive (3 +). The rate of HER2 2 + , 1 + , and 0 + was 4%, 32%, and 24%, respectively, in non-SDCs. HER2-low (1 + or 2 +) was seen in 62% of myoepithelial carcinomas, 0% of adenoid cystic carcinomas, 56% of acinic cell carcinomas, and 33% of carcinomas not otherwise specified. HER2-ultra-low (0 +) was observed in 23% of myoepithelial carcinomas, 33% of adenoid cystic carcinomas, 22% of acinic cell carcinomas, and 11% of carcinomas not otherwise specified. Although HER2-positive (3 +) was seen only in SDC, HER2-low and HER2-ultra-low expressions were not uncommon across salivary gland carcinomas, including SDCs and various non-SDC types. These findings suggest the potential applicability of HER2-targeted therapy in salivary gland carcinomas.

Digital pathology (DP) is reshaping diagnostic workflows, offering enhanced accuracy, efficiency, and collaboration through high-resolution slide scanning, artificial intelligence (AI), and cloud-based infrastructure. In Tuscany, the adoption of DP is framed within a regionally integrated healthcare system composed of three local health authorities and four university hospitals, coordinated under a hub-and-spoke model. This structure supports the potential for widespread DP implementation, leveraging centralized expertise and shared digital infrastructure. A region-wide survey involving all public pathology centers in Tuscany confirmed that all institutions are already equipped with at least one whole slide scanner. Building on this foundation, the region has initiated a strategic transformation stepwise process to implement and progressively expand DP workflows. Key actions included the adoption of a common regional laboratory information system (LIS), the development of a centralized cloud repository ensuring secure data access, and the design of telepathology modules to enable remote consultations and second opinions. Dedicated training programs for technical staff and the progressive introduction of AI-assisted tools are also part of this roadmap, ensuring readiness for routine clinical integration. The benefits of DP in Tuscany are manifold: faster diagnostic turnaround, improved inter-institutional collaboration, standardized reporting, and opportunities for research and education. Integration of AI-assisted tools is expected to support routine diagnostics, especially in high-volume and complex cases. The regional network also creates a foundation for multi-omics integration and computational pathology research. To ensure successful implementation, the region adopted a phased, scalable approach backed by regulatory alignment and continuous professional development. A unified DP network with shared protocols and centralized resources will be crucial. Tuscany's experience may serve as a blueprint for other regions aiming to transition toward a digital, AI-powered pathology ecosystem aligned with the broader goals of precision medicine.

This study aimed to characterize the tumor microenvironment (TME) in patient-derived xenograft (PDX) models of oral squamous cell carcinoma (OSCC) and compare histological findings with primary tumors of origin (PTT). OSCC samples from five donor patients were implanted into NOD/SCID mice (PDX0) and subsequently re-implanted into new animals (PDX1), yielding three groups for analysis: PTT, PDX0, and PDX1 (n = 5 each). Histological slides with sections were stained with hematoxylin and eosin for grade analysis and subjected to immunohistochemical reactions with antibodies against SMA, CD4, CD8, CD31, CD34, Claudin-1, Vimentin, and Ki-67. Multiple comparisons were performed between samples (PTT, PDX0, and PDX1). The histological grade of PDX0 and PDX1 tumors showed instability across passages. The expression of SMA, claudin-1, vimentin, and Ki-67 was maintained, with no significant differences between PDX0 and PDX1 when compared with PTT. In contrast, the expression of CD4, CD8, CD31, and CD34 was significantly reduced in PDX0 and PDX1 tumors compared with PTT. OSCC PDX tumors may exhibit instability in the degree of differentiation compared with the donor tumors across passages, as well as alterations in certain components of the TME, including cancer-associated fibroblasts, epithelial-mesenchymal transition-related features, and cellular proliferation characteristics.

Diagnostic challenges remain in desmoid fibromatosis (DF) due to somewhat frequent β-catenin immunohistochemical negativity, risking misclassification and overtreatment. The present study evaluates the role of CTNNB1 molecular testing in optimizing diagnosis. A single-center, large retrospective analysis of 780 patients with DF was performed. The incidence of DF was higher in females, particularly within the adult demographic. 77.3% of DF cases exhibited nuclear β-catenin positivity.The majority of cases that were β-catenin nuclear negative underwent CTNNB1 exon 3 Sanger sequencing.Molecular analysis revealed that 74.1% of β-catenin negative cases harbored CTNNB1 mutations, primarily at codon 41 (p.T41A). Patients with wild-type CTNNB1 were significantly older. Notably, β-catenin IHC showed higher positivity in resected specimens (79.7%) compared to biopsies (62.0%), whereas CTNNB1 mutational detection was higher in biopsies (93.5%) than resections (76.8%). Codon 41 mutations correlated with higher β-catenin IHC positivity than codon 45 mutations. A subsequent analysis of age demonstrated that DF in the abdominal wall, retroperitoneal cavity, and trunk was more likely to occur in the adult group. Four novel mutations (p.S45_G48del, p.T41V, p.S23N, and p.G34E) were identified. CTNNB1 mutational testing is indispensable for the diagnosis of β-catenin-negative DF, especially in older patients, where IHC limitations are pronounced. Identifying CTNNB1 gene mutations provides an accurate diagnosis in challenging cases without immunohistochemical support, facilitating the development of more effective treatment strategies.

The co-expression of myeloid and B-cell antigens is characteristic of mixed-phenotype acute leukemia (MPAL)-B/myeloid. This finding can also be observed in AML with t(8;21)(q22;q22)/RUNX1::RUNX1T1, as well as in cases of AML with other RUNX1 rearrangements, copy number gains, or mutations. AML with plasmacytoid dendritic cell (pDC) differentiation (pDC-AML) containing clonally-related myeloblasts and neoplastic pDCs, are enriched for RUNX1 mutations and have been shown to exhibit B-cell marker expression. Here, we present two cases of pDC-AML with B-cell marker expression in which RUNX1 aberrations were not identified. Although previously we speculated on the role of RUNX1 in the aberrant expression of B-cell markers such in cases, the absence of RUNX1 lesions in the current cases supports the potential inherent ability of pDCs to express B-cell markers during maturation.