Since their first inception, neuroendocrine neoplasms of the breast have undergone many iterations of classification and definition. Taken together with their extremely low incidence, the ever-evolving landscape has made diagnosis, treatment, and research exceedingly challenging.

Our patient is a 45-year-old female who had a breast mass with clinical workup favoring a breast primary. A diagnosis of small cell carcinoma was established after an extensive clinical and pathologic workup. The mass did not respond to traditional neoadjuvant platinum-based chemotherapy, and she underwent a total mastectomy. Shortly thereafter, imaging revealed widely metastatic disease involving the brain, chest, abdomen, and pelvis. She received whole-brain radiation and, given the previous lack of response to chemotherapy, was recommended to try off-label tarlatamab. To date, with a short-term follow-up of 5 months, after whole-brain radiotherapy administered concurrently with the first cycle of tarlatamab, subsequent imaging showed near-complete radiographic resolution of extracranial metastatic disease, while the brain lesions also showed radiographic resolution on follow-up MRI.

We report the novel and preliminary use of tarlatamab in a patient with small cell neuroendocrine carcinoma of the breast, with short-term follow-up. We also discuss the most critical challenges associated with this rare pathologic diagnosis and the important elements to consider to ensure that metastatic disease is excluded.

Colorectal cancer is a major cause of cancer morbidity and mortality worldwide, including in China. Screening can facilitate earlier detection and reduce disease burden, while primary healthcare institutions are central to population outreach, risk assessment, referral, and follow-up. However, resource constraints, limited public awareness, low screening adherence, and fragmented coordination continue to hinder implementation in community and rural settings. This mini review summarizes the epidemiological and health-economic rationale for colorectal cancer screening in primary healthcare and discusses organizational models, risk-stratified screening and referral, workforce training, quality control, data management, and information sharing. Available evidence supports coordinated pathways that link noninvasive initial screening to timely colonoscopy and follow-up, supported by clear governance, trained personnel, and traceable data systems. The ongoing Yazhou District program is included briefly as a descriptive example of how these components may be organized in practice. Future research should evaluate uptake, positivity, colonoscopy completion, lesion detection, adverse events, costs, and longer-term outcomes in diverse primary-care settings.

Traumatic brain injury (TBI) induces neuroimmune activation and metabolic reprogramming in microglia, but the transcriptional regulators underlying these responses remain unclear. This study aimed to integrate single-cell and bulk transcriptomic datasets to identify microglia-associated regulatory genes and characterize their potential roles in post-TBI neuroinflammatory and immunometabolic dysregulation.

We integrated single-cell RNA sequencing data (GSE101901) with a bulk training dataset (GSE58485) and an independent bulk validation dataset (GSE242025) from murine TBI models. hdWGCNA, differential expression, pseudotime, CIBERSORT, and in silico transcription factor binding-site analyses were performed to identify and characterize candidate genes. Key-gene expression was additionally validated by RT-qPCR in male C57BL/6 mice assigned to Sham and TBI groups (n = 5 per group). The Drug Gene Interaction Database was used for exploratory drug-gene prediction.

Single-cell profiling suggested descriptive shifts in the proportions of microglia, astrocytes, and neurons after TBI. hdWGCNA identified 90 microglia-associated genes, 43 of which overlapped with nominally differentially expressed genes; 89 genes met the Benjamini–Hochberg-adjusted P < 0.05 threshold in the bulk analysis. Cross-dataset validation identified increased Ccl4 and Lgals3 expression and decreased Egr1 expression. Motif scanning identified four predicted EGR1 motif occurrences in the Ccl4 promoter and six occurrences at three unique locations in the Lgals3 promoter. RT-qPCR in TBI and Sham mice (n = 5 per group) supported the same directional expression changes in Ccl4, Lgals3, and Egr1.

A candidate Ccl4/Lgals3/Egr1 expression pattern characterized by Ccl4 and Lgals3 upregulation and Egr1 downregulation was associated with post-TBI neuroinflammatory and immunometabolic changes. Further mechanistic validation is required.

Hepatic sinusoidal obstruction syndrome (SOS) is characterized by hepatic sinusoidal endothelial cell injury and detachment, hepatic sinusoidal congestion, and hepatic cell necrosis. Currently, limited data exist concerning changes during the recovery period, especially histopathological changes. The purpose of this study was to investigate the evolution of pathology in patients with pyrrolizidine alkaloid (PA)-induced SOS and in a monocrotaline-induced SOS rat model.

Patients diagnosed with PA-induced SOS who underwent liver biopsy after achieving clinical remission were consecutively enrolled in this retrospective study. To compare the clinical and pathological differences between patients with acute and convalescent SOS, a 2:1 matched analysis was performed based on age, sex, treatment regimen, and baseline Drum Tower Severity Scoring (DTSS) during the acute phase. Additionally, an animal model of PA-induced SOS was established through the administration of monocrotaline.

Fourteen consecutive patients with SOS who had adequate liver biopsy specimens obtained during recovery were identified. During convalescence, most laboratory and imaging findings, such as the map-like enhancement observed on computed tomography, also disappeared. However, histopathological analysis revealed a distinct shift from hepatic sinusoidal endothelial cell injury in the acute phase to portal tract abnormalities, primarily characterized by portal vein stricture, in the recovery phase. These pathological changes were corroborated in our animal model.

Our study suggests that both patients with PA-induced SOS and rats in the convalescent stage may exhibit porto-sinusoidal vascular disease-like changes. Regular follow-up and dynamic pathological assessment are therefore recommended to facilitate the early detection of potential signs of portal hypertension.

Biliary duct invasion (BDI) is an underrecognized growth pattern of colorectal cancer (CRC) liver metastases that can mimic intrahepatic cholangiocarcinoma or intraductal papillary neoplasm of the bile duct. Its prevalence and clinicopathologic associations remain unclear. This study aimed to determine the prevalence of BDI and its clinicopathologic associations in surgically resected CRC liver metastases.

We retrospectively analyzed 133 consecutive patients who underwent hepatic resection for CRC liver metastases. Clinicopathologic variables, including age, sex, resection type, tumor differentiation, lymphovascular invasion (LVI), tumor budding, surgical margin status, and primary tumor characteristics, were compared between BDI-positive and BDI-negative cases. Categorical variables were analyzed using the chi-square, Fisher exact, or Fisher-Freeman-Halton exact test, as appropriate; continuous variables were analyzed using the Mann-Whitney U test.

BDI was identified in 19 of 133 cases (14.3%). Male sex showed the strongest numerical trend toward BDI (84.2% vs. 61.4%, P = 0.096), and LVI showed a nonsignificant numerical trend toward higher BDI rates (26.3% vs. 12.3%, P = 0.149). No clinicopathologic variable in the primary cohort analysis reached statistical significance after Bonferroni correction (α = 0.0050).

BDI occurs in approximately 14% of surgically resected CRC liver metastases in this cohort. Male sex and LVI show nonsignificant numerical trends toward higher BDI rates, but these findings should be interpreted cautiously given the limited sample size. Accurate histopathologic recognition of BDI and its distinction from intrahepatic cholangiocarcinoma remain important for correct pathologic diagnosis. Further prospective studies are warranted to clarify the clinicopathologic and prognostic significance of BDI.

Estrogen receptor alpha, encoded by the ESR1 gene, is a major oncogenic driver in hormone receptor-positive/HER2-negative breast cancers. While endocrine therapies are effective in treating this subgroup, patients with advanced or metastatic disease may develop resistance associated with acquired somatic ESR1 mutations. This mini review summarizes recent clinical and technological advances in understanding ESR1 mutations, newly approved targeted therapies, and the use of liquid biopsy companion diagnostics, with a focus on their implications for pathologists.

We conducted a narrative review of PubMed-indexed literature and relevant regulatory and guideline sources related to ESR1 in breast cancer, with an emphasis on recent peer-reviewed studies of ESR1 mutations and clinical trials of emerging therapies.

This review describes the molecular features of ESR1 alterations and estrogen receptor pathway biology, the mechanisms and key trial data for recently approved ER-targeted therapies for ESR1-mutated breast cancer. Additionally, it evaluates liquid biopsy testing platforms for detecting ESR1 mutations, discusses the advantages and limitations of liquid biopsy in detection of treatment resistance, and considers the evolving role of pathologists in breast cancer care.

Acquired ESR1 mutations are major drivers of endocrine therapy resistance. Next-generation sequencing and liquid biopsy have increasingly informed the clinical management of breast cancer in the past decade. Pathologists can play an important role in implementing molecular testing, interpreting complex biomolecular data, and helping to guide timely treatment decisions in the era of precision oncology.

EWSR1 fusions are recurrent genetic alterations in a wide spectrum of mesenchymal tumors and are often associated with specific clinicopathologic entities. However, the presence of an EWSR1 rearrangement does not always indicate a functional or disease-defining fusion.

We report a case of undifferentiated pleomorphic sarcoma with high-grade morphologic features harboring an EWSR1 rearrangement detected by fluorescence in situ hybridization. It was subsequently characterized by RNA sequencing as a likely nonfunctional fusion of EWSR1 exon 1 and NF2 intron 1. Histologically, the tumor was composed of pleomorphic spindle cells with brisk mitotic activity and lacked a specific line of differentiation. Immunohistochemically, the tumor showed diffuse cytoplasmic S100 positivity, with nuclear staining in a subset of tumor cells, while the overall immunophenotype did not support a specific line of differentiation. The EWSR1::NF2 fusion was inferred to have a tail-to-tail configuration, and additional KRAS and TP53 alterations were detected.

This case highlights that an EWSR1 rearrangement detected by fluorescence in situ hybridization should be interpreted cautiously and does not necessarily represent a functional or disease-defining fusion. Comprehensive molecular evaluation is important for the accurate interpretation and classification of sarcomas with atypical EWSR1 rearrangements.

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a multifactorial disorder driven by complex interactions among genetic, epigenetic, transcriptional, proteomic, metabolic, and microbiome factors. Single-omics technologies have provided valuable insights into disease mechanisms, yet each layer captures only a partial view of MAFLD pathogenesis. Recent advances in multi-omics integration allow systematic dissection of molecular networks, cell differentiation trajectories, intercellular communication, and spatial organization, revealing causal links between molecular alterations and tissue phenotypes. Horizontal integration connects different omic layers within the same biological state, while longitudinal integration captures dynamic changes across disease stages. Emerging spatial transcriptomics, proteomics, and metabolomics techniques further enable in situ mapping of cellular and molecular heterogeneity, uncovering spatially defined pathogenic niches and regulatory hubs. Collectively, these integrated approaches offer a multidimensional framework for understanding MAFLD progression, identifying potential biomarkers, and guiding precision therapeutic strategies. Future efforts should focus on standardized multi-omics pipelines, interdisciplinary collaboration, and functional validation to translate these insights into clinical applications.