Medicine and Pharmacology

Abstract: Histopathologic melanoma diagnosis extends beyond melanocytic cytology to encompass non-melanocytic features: solar elastosis patterns, stromal regression, adnexal relationships, epidermal reaction patterns, and the host inflammatory response. These “old school” low-power clues are particularly valuable on sun-damaged skin, where benign nevi, reactive melanocytic hyperplasia, and melanoma in situ share overlapping features. Quantitative data support two elastosis-based signs: the “umbrella sign” (reduced elastosis beneath the lesion’s central third; PPV for nevus 96%, NPV for melanoma 74%; calculated from raw cohort data) and the “purple fiber sign” (100% specificity, 30% sensitivity for nevus), both from a cohort of 81 actinically damaged lesions. Regression-identified by compressed elastic layers displaced to the reticular dermis, fibrosis, melanophages, and inflammation-aids diagnosis but complicates distinction from surgical scar. The maturation state of tertiary lymphoid structures (TLS) within the regression zone, ranging from immunosuppressive immature aggregates to anti-tumoral mature structures with germinal centers, may explain the variable prognostic significance of histologic regression. Epidermal hyperplasia over thick melanomas reflects angiogenesis-related changes, while effacement is a practical red flag in spitzoid lesions. Ancillary tests are most productive when morphology has already framed the differential. These non-melanocytic clues remain indispensable as the foundation for rational ancillary testing.

Abstract: Background: Renal cell carcinomas (RCC) represent neoplasms with variable biological behaviour. Some remain difficult to classify within the current diagnostic framework. Clear cell papillary renal cell tumour (CCPRCT) is now recognized as an indolent entity, whereas renal cell carcinoma with fibromyomatous stroma (RCCFMS) remains a provisional subtype with partially overlapping morphological features. Methods: We analysed a multifocal RCC with clear cell morphology and prominent fibromyomatous stroma using whole-genome and RNA sequencing. The molecular profile was compared with the Cancer Genome Atlas (TCGA) pan-cancer dataset including 885 RCC cases. Histological re-evaluation of 10 identified similar cases was performed. Transcriptional data was mined for potential markers which were validated in an independent cohort. Results: The ten TCGA cases with similar transcriptomic features were characterized by diploid genomes, absence of recurrent chromosomal alterations and lack of VHL gene mutations. Reduced VHL mRNA expression was observed, with increased methylation at selected CpG sites consistent with possible epigenetic down-regulation. Histological re-evaluation by three urological pathologists identified diagnostic variability. Differential expression analysis highlighted cytokeratin 17 (KRT17) and collagen 17A1 (COL17A1) as candidate markers. Immunohistochemical evaluation in a small (n = 6) independent cohort of CCPRCT demonstrated expression of both markers, whereas tissue microarrays of 257 clear cell and 68 papillary RCC cases were found to be negative. Conclusions: These findings suggest that a subset of renal tumours with overlapping morphological features of CCPRCT and RCCFMS may share common molecular characteristics. These observations are exploratory and hypothesis-generating, and further studies in larger, well characterized cohorts are required to clarify the biological and diagnostic significance of this subgroup.

Abstract: Cutaneous metastases represent a relatively rare but clinically significant manifestation of advanced internal malignant neoplasms, occurring in approximately 0.7% to 10.4% of all cancer patients. Because cutaneous metastases can occasionally serve as the first indication of an occult internal malignant neoplasm, their accurate and timely diagnosis is of paramount importance. However, distinguishing cutaneous metastases from primary cutaneous neoplasms, particularly malignant cutaneous adnexal tumors, poses a diagnostic challenge in dermatopathology due to significant clinical and histomorphologic overlap. Here, we review the current literature on the epidemiology and clinical presentation of cutaneous metastases, emphasizing the importance of clinicopathologic correlation. While histologic features such as a purely dermal/subcutaneous location, intravascular tumor emboli, and a "bottom-heavy" architecture suggest metastasis, the presence of an in situ component or morphologic transition from a benign precursor lesion strongly supports a primary cutaneous origin. Furthermore, we detail the utility of optimized immunohistochemical panels, highlighting the diagnostic value of markers such as p63, cytokeratin 15, calretinin, and D2-40 (podoplanin) in confirming primary adnexal lineage. We also explore recent advances in molecular biology and comprehensive genomic profiling, discussing how the identification of specific gene fusions (e.g., MYB::NFIB, CRTC1::MAML2, YAP1 fusions) and mutational signatures can resolve ambiguous cases and provide critical insights into lineage. Finally, we provide a comprehensive, practical diagnostic algorithm for differentiating primary cutaneous adnexal carcinomas from cutaneous metastases of adenocarcinomas. By integrating traditional histopathologic techniques with modern immunohistochemical and molecular techniques, pathologists and clinicians can successfully navigate this complex differential diagnosis and thereby facilitate appropriate patient management and therapeutic intervention.

Abstract: Background/Objectives: Diffuse large B-cell lymphoma (DLBCL) is an aggressive lymphoma and one of the most common hematological neoplasia. Entropy is a statistical measure of randomness that can be used to characterize the texture of an input image and measure tissue complexity. Methods: Image processing and computer vision analysis were performed on a series of 114 diagnostic DLBCL cases and 44 reactive lymphoid tissues stained with hematoxylin & eosin (H&E). Histological entropy was measured to differentiate between reactive lymphoid tissue and DLBCL and predict clinical evolution. Gene expression analysis using the NanoString nCounter PanCancer Immune Profiling Panel was performed in 29 cases. Results: Comparison with reactive lymphoid tissue, DLBCL was characterized by lower entropy (7.3 ± 0.2 vs. 6.8 ± 0.6; P < 0.001, respectively). Within the DLBCL diagnostic category and at patient-level analysis, higher entropy was associated with poor overall survival and death events within the first 2 years (hazard-risk = 2.4, P = 0.004) and lower entropy with a moderate and more favorable outcome (hazard-risk = 0.4, P = 0.004). High entropy was also correlated with ECOG performance status ≥ 2, lower protein expression of apoptosis markers of cPARP and cCASP3, and upregulation and downregulation of specific immuno-oncology genes. Conclusion: The histological evaluation of entropy is useful for both the differential diagnosis of reactive lymphoid tissue and DLBCL and can be used as a predictor factor of DLBCL prognosis.

Abstract: TLS are ectopic, non-encapsulated aggregates of immune cells that develop de novo in non-lymphoid tissues in response to persistent antigenic stimulation, and have emerged as clinically relevant features of many solid tumours. However, conventional TLS assessment based on presence/absence, density, or simplified maturation scales does not adequately explain why TLS are associated with favourable, neutral, or even adverse clinical outcomes across tumour types and treatment settings. In this review, we synthesize current biological, spatial, and clinical evidence and argue that TLS should be interpreted not as static histologic findings, but as functional immune niches shaped by three interacting axes: structural maturity, spatial localization, and functional immune context. We discuss how mature germinal centre-positive TLS often reflect coordinated B-cell–T-cell cooperation and sustained antigen-driven antitumour immunity, whereas partially organised or suppressive TLS may display transitional or immunoregulatory properties. On this basis, we propose a pragmatic, pathology-oriented conceptual framework that groups TLS into three simplified functional states: TLS-A, representing mature effector TLS with germinal centre activity; TLS-B, representing organised but incompletely matured or functionally intermediate TLS; and TLS-C, representing TLS dominated by regulatory or suppressive immune programs. We further place these states within recurrent tumour microenvironment archetypes and outline the rationale for a “functional TLS score” integrating histopathologic and molecular readouts. Rather than introducing a definitive biological taxonomy, this framework is intended as a translational model for harmonising TLS interpretation, refining biomarker development, and supporting future studies on prognosis, immunotherapy response, and standardised pathology reporting in solid tumours.

Abstract: Background/Objectives: Despite Hematoxylin and eosin (H&E) staining remains the cornerstone of histopathological diagnosis, substantial intra- and inter-laboratory variability persists. This issue is increasingly relevant in Digital Pathology, where staining inconsistency may affect whole-slide image interpretation and the performance of image analysis algorithms. In the present work, we evaluated the diagnostic adequacy and non-inferiority of a novel tabs-based H&E staining method compared with conventional liquid reagents. Methods: Fifty formalin-fixed paraffin-embedded tissue samples from routine practice were sectioned in duplicate and stained either conventionally or using H&E Stain Tabs. After slide review, 14 representative tissue samples were selected, scanned at 40x magnification, and used to generate 24 matched image pairs at different magnifications. A blind online survey was completed by 13 expert pathologists using high-quality monitors. Participants assessed overall staining preference and rated stromal, epithelial, cytoplasmic, and nuclear staining quality. Non-inferiority was tested using a predefined margin of −0.10, and paired rating differences were analyzed using the Wilcoxon signed-rank test. Results: Across 312 paired evaluations, the tabs-based method was preferred in 120 cases (38.5%), conventional staining in 118 cases (37.8%), and no preference was expressed in 74 cases (23.7%). The tabs-based method met the criterion for non-inferiority compared with standard staining (z = 2.7). Rating-scale analysis showed significantly better stromal evaluation with the tablet-based method (z = 2.638; p = 0.008), whereas no significant differences were observed for epithelial, cytoplasmic, or nuclear staining. All evaluated images were considered diagnostically adequate. Conclusions: The tabs-based H&E stain was non-inferior to the conventional method and showed particularly favorable performance in the assessment of stromal components. These findings support its potential role in improving staining reproducibility and standardization, particularly in Digital Pathology workflows where pre-analytical and analytical consistency is critical.

Abstract: Background/Objectives: Early prediction of clear cell renal cell carcinoma (ccRCC) metastasis helps differentiate patients for more appropriate therapies. MicroRNAs (miRNAs) - miR-10b-5p, miR-130b-3p, miR-139-5p and miR-199b-5p - have been found highly associated with ccRCC metastasis in frozen tumor tissue. In this study, we determine the risk status of ccRCC metastasis, specifically for FFPE tumor speci-mens. Methods: Using the risk score method and a formalin-fixed paraffin-embedded (FFPE) tissue training cohort (n=28) of localized and metastatic ccRCC samples, we built a quantitative PCR-based miRNA signature. With the defined risk score cutoffs, we stratified patients into high risk, low risk, and equivocal groups. We validated the signature in a 265-case test cohort of FFPE primary ccRCC specimens. Results: For all the patients predicted to be at high or low risk, the overall sensitivity and specificity for the signature were 80% and 76% (OR=6.60, 95%Cl=2.54-17.13, p=0.0001), respectively. The sensitivities and specificities were 72% and 78%, 70% and 67%, 78% and 75% for stages I, II and III patients, respectively. The signature was also well correlated with cancer-specific survival of patients (HR=3.06, 95%Cl=1.49-6.93, p=0.004). Conclusion: This FFPE specimen-specific miRNA signature can predict ccRCC metastasis and prognosis in routine FFPE tumor specimens, to help to stratify patients for more appropriate treatment.

Abstract: Background/Objectives: Chromosomal microarray analysis (CMA) is an essential tool in modern cytogenetics for detecting copy number alterations and copy-neutral loss of heterozygosity (CN-LOH). As optical genome mapping (OGM) emerges as a potential replacement for traditional cytogenetic methods, the extent to which CMA remains necessary in routine diagnostic workflows remains to be elucidated. Methods: We retrospectively reviewed 53 primary neoplastic cases in which CMA identified one or more CN-LOH events. Event size, genomic content, and correlation with next-generation sequencing (NGS) findings were assessed. A separate cohort of newly diagnosed B-cell acute lymphoblastic leukemia (B-ALL) was analyzed to evaluate disease-specific CN-LOH frequency. Results: Nearly half of CN-LOH events detected were &lt;25 Mb, below the current detection threshold of OGM. Many encompassed clinically relevant genes, including FLT3, JAK2, TET2, TP53, and RUNX1. Additionally, two-thirds of cases harbored pathogenic or likely pathogenic variants by NGS within the corresponding CN-LOH regions, further underscoring the clinical value of detecting these copy-neutral events. In contrast, CN-LOH was uncommon in B-ALL, and most alterations identified by CMA would be detectable by OGM. Many of these patients also harbored complex structural rearrangements that required multiple conventional assays for full characterization; these could be resolved by OGM in a single analysis. Conclusions: Our findings indicate that although OGM excels at resolving complex structural variants, CMA remains essential for detecting copy-neutral events. Until OGM achieves improved sensitivity for CN-LOH, an integrated approach utilizing conventional cytogenetics, CMA, NGS, and OGM provides the most reliable framework for comprehensive genomic assessment across cancer types.

Abstract: Fibroblast growth factor receptor 2b (FGFR2b) has become an increasingly important therapeutic target in gastric and gastroesophageal junction cancer, particularly with the clinical development of FGFR2b-directed antibody therapy. However, its translation into routine treatment selection is not straightforward. FGFR2b is usually assessed as a protein biomarker by immunohistochemistry, and a positive result may reflect different biological situations depending on staining intensity, percentage of positive tumor cells, sample type and spatial distribution. In addition, FGFR2b protein expression, FGFR2 amplification, transcript-level activity and true pathway dependency are related but not interchangeable. This review examines FGFR2b-positive gastric cancer from the perspective of biomarker reliability rather than target presence alone. We discuss the biological basis of FGFR2b targeting, the reasons for variability in reported positivity rates, the implications of intratumoral and inter-lesion heterogeneity, the current clinical evidence for FGFR2b-directed and broader FGFR-targeted approaches, and the emerging challenges of safety, resistance and treatment sequencing. Particular attention is given to the gap between detecting FGFR2b and identifying tumors in which this target is sufficiently expressed, representative and biologically relevant to guide therapy. We also consider how FGFR2b should be interpreted alongside HER2, CLDN18.2, immune biomarkers and other receptor tyrosine kinase alterations. As FGFR2b-directed strategies move forward, their success will depend not only on drug efficacy, but also on standardized testing, careful reporting, and selective reassessment when disease biology changes. FGFR2b therefore offers a useful model for how protein biomarkers can be developed in gastric cancer: not as isolated positive-or-negative la-bels, but as clinically interpreted variables within a changing therapeutic landscape.

Abstract: Neuroendocrine differentiation in tumors of the female genital tract is an uncommon but diagnostically consequential finding. Its interpretation is challenging because neuroendocrine marker expression does not necessarily define a neuroendocrine neoplasm. Focal or aberrant staining for synaptophysin, chromogranin A, CD56 or INSM1 may occur in otherwise conventional gynecologic carcinomas, whereas true poorly differentiated neuroendocrine carcinomas represent aggressive tumors with distinct prognostic and therapeutic implications. This narrative review examines neuroendocrine differentiation across the cervix, endometrium, ovary, vagina and vulva from an integrated clinicopathologic perspective. We emphasize that neuroendocrine differentiation should be approached as a diagnostic and biological spectrum, ranging from incidental immunophenotypic expression to carcinoma with neuroendocrine differentiation, mixed neuroendocrine/non-neuroendocrine tumors, well-differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas. Morphology remains the diagnostic anchor, while immunohistochemistry, molecular context and clinicoradiologic correlation refine classification and help exclude mimics or metastatic disease. Site-specific interpretation is essential: cervical neuroendocrine car-cinoma is commonly HPV-associated and clinically aggressive; endometrial tumors require integration with p53, mismatch repair, POLE and SWI/SNF-related contexts; ovarian lesions demand distinction between primary well-differentiated neuroendocrine tumors, poorly differentiated carcinomas and metastases; and vaginal or vulvar tumors require careful exclusion of adjacent extension, cutaneous mimics and extragenital primaries. We propose a practical diagnostic framework that separates incidental marker expression from clinically meaningful neuroendocrine differentiation and links this distinction to reporting, prognosis and treatment. The central diagnostic question is not whether neuroendocrine markers are expressed, but whether their expression defines a morphologically, biologically and clinically meaningful tumor category.

Abstract: Background: Penile squamous cell carcinoma (pSCC) is a global health burden with poor systemic treatment efficacy for advanced disease, relying on pathway-agnostic regimens despite two distinct carcinogenic pathways (HPV-driven vs. HPV-independent). We conducted an integrative review to systematically compare the tumor immune microenvironment (TIME) of HPV-driven and HPV-independent pSCC to guide immunotherapy stratification. Methods: An integrative review of 21 studies, including single-cell/spatial transcriptomics and a Phase II clinical trial, synthesized evidence from over 4,500 pSCC patients published between January 2020 and April 2026. Results: HPV-positive pSCC presents an immunologically active but partially suppressed TIME, defined by significantly higher CD8+ T-cell infiltration and lower immune checkpoint co-expression and exhaustion (e.g., TIGIT). HPV-negative tumors exhibit a broadly immunosuppressive niche marked by elevated PD-L1 prevalence (51.4% pooled), increased regulatory T-cell and M2-macrophage polarization, and multi-checkpoint co-exhaustion (PD-1, TIM-3, LAG-3). PD-L1 overexpression is associated with shorter cancer-specific survival. Clinically, HPV positivity and CD8+ T-cell density independently predicted progression-free survival benefit from atezolizumab. Conclusion: These findings establish HPV status and TIME composition as actionable determinants of immunotherapy benefit. We recommend prospective integration of HPV testing and tumor-infiltrating lymphocyte quantification into future randomized trials to guide patient selection and explore combinatorial checkpoint blockade, particularly for the multi-exhausted HPV-negative disease subset.

Abstract: Background: Highly active antiretroviral therapy (HAART) has transformed HIV into a manageable chronic condition but is associated with dyslipidemia, increasing cardiovascular disease (CVD) risk. Data on lipid profile alterations in rural South Africa primary healthcare settings remain limited despite high HIV burdens. The purpose of the study was to determine the prevalence of lipid profile alterations among adult HIV patients receiving HAART at rural Eastern Cape primary healthcare facilities. Methods: Retrospective cross-sectional analysis of clinical and laboratory records from 370 adults (>18 years) on HAART at five OR Tambo District health care facilities (2020 – 2024) Lipid parameters (Total cholesterol {TC} LDL Cholesterol< HDL cholesterol, Tri-glycerides {TG} from National Health Laboratory Services (NHLS) data base were assessed NCRP ATP III thresholds. Prevalence was calculated with SPSS v29.0; overall dyslipidemia defines as any abnormality. Results: High prevalence of lipid alterations was observed: hypercholesterolemia 53.8 % (199/370). Overall dyslipidemia affected 80.8 % (299/370) of patients, confirming substantial metabolic burden in this rural cohort. Conclusion: Over 80% of rural HAART patients exhibited dyslipidemia predominantly elevated LDL-cholesterol, LDL+C (61.4%) and triglycerides (60.5%) Findings underscore urgent need for routine lipid screening, regimen optimization toward integrase strand transfer inhibitors. (INSTIs) and NCD-HIV integration in South Africa’s primary healthcare system to mitigate CVD risk.

Abstract:

Background/Objectives: Mucopolysaccharidosis type III (MPS III, Sanfilippo syndrome) is an autosomal recessive lysosomal storage disorder caused by deficiencies in enzymes required for heparan sulfate degradation. While primarily recognized for its devastating neurodegenerative course, the systemic extent of glycosaminoglycan (GAG) accumulation remains under-characterized. This study aims to provide a detailed multisystemic pathological mapping of MPS III to challenge the traditional "brain-only" disease paradigm and highlight the clinical relevance of extracerebral involvement. Methods: We present a comprehensive clinicopathological analysis of a 15-year-old female patient with a history of profound neuropsychomotor delay, refractory epilepsy, and spastic tetraplegia. Following her death due to terminal bronchopneumonia during palliative care, a complete forensic and pathological autopsy was conducted. Tissue samples from all major organ systems were processed using routine Hematoxylin-Eosin (HE) staining alongside specialized histochemical stains to identify intracellular storage products. Results: Macroscopic evaluation revealed significant diffuse cerebral atrophy, meningoencephalic edema, cardiac valvulopathy with compensatory myocardial remodeling, and hepatosplenomegaly. Furthermore, erosive gastrointestinal lesions and degenerative renal changes were identified. Histopathological examination confirmed widespread cytoplasmic vacuolization across diverse cell populations, including neurons, hepatocytes, renal tubular cells, and the reticuloendothelial system. These findings demonstrate that GAG deposition is a generalized process affecting nearly every parenchymal structure. Conclusions: Although neurological decline dominates the clinical phenotype, our findings underscore that MPS III is a true systemic storage disorder. Significant involvement of the cardiovascular and visceral systems contributes to the disease's complexity and mortality. This case reinforces the critical diagnostic value of a comprehensive autopsy in delineating the full morphological spectrum of Sanfilippo syndrome, providing essential insights for multidisciplinary management.

Abstract: Diffuse large B-cell lymphoma (DLBCL) is one of the most frequent lymphomas. This proof-of-concept study predicted the prognosis of DLBCL using hematoxylin and eosin (H&E) histological images, computer vision and deep learning. The series included 114 DLBCL cases, split into 2 prognostic groups according to the overall survival, and 44 reactive lymphoid tissue. The curve fitting and slope analysis showed a point of inflection at 2 years, which differentiated patients with aggressive clinical evolution (“Dead < 2 years”, b1 = -0.024), from the rest with moderate clinical evolution (“Others”, b1 = -0.003). Twenty different convolutional neural networks (CNNs) were used, and explainable artificial intelligence (XAI) was also applied. The final model based on DarkNet-19 predicted prognosis groups with high performance (test set accuracy = 96.3%). The other performance parameters were precision (94.5%), recall (95.0%), false positive rate (3.1%), specificity (96.9%), and F1 score (94.7%). XAI, including grad-CAM, occlusion sensitivity, and image-LIME, confirmed that the CNN focused on the correct areas. Hybrid partitioning to prevent information leakage with patient-based analysis, image classification between DLBCL and 44 cases of reactive lymphoid tissue, and hyperparameter tuning were also successfully performed. Correlation with the clinicopathological characteristics found that the Dead < 2 years group was correlated with stage III-IV, International Prognostic Index (IPI) High + High/intermediate, progressive disease, non-GCB cell-of-origin, CD10-, BCL2+, and Epstein-Barr virus (EBER)+. Analysis of the microenvironment, immune checkpoint, cell cycle, and germinal center markers showed that Dead < 2 years had higher IL10, PD-L1, and CD163, and lower E2F1 protein expressions. No differences were found for Ki67, CSF1R, CASP8, TNFAIP8, LMO2, MYC, MDM2, CDK6, and TP53 markers at quantitative level. In conclusion, the DLBCL overall survival can be predicted using H&E histological images and deep learning using 2 years point (similar to POD24). This trained CNN can be used as a pretrained model for transfer learning in the future.

Abstract: Background/Objectives: Critical limits represent quantitative thresholds of life-threatening diagnostic test results that require immediate clinician notification and may necessitate life-saving intervention to prevent adverse outcomes. Our goals are to report point-of-care critical limits for adults and newborns from a comprehensive U.S. national database, to identify POC instruments associated with the critical limits, and to support the harmonization of POCT practice. Methods: We gathered critical limit notification lists from 417 hospitals across all 50 states and Washington D.C., comprising university hospitals, trauma and heart centers, centers of excellence, community hospitals, and network hospitals. We extracted point-of-care critical limits, central laboratory critical limits (at hospitals with POC), adult international normalized ratio (INR) data, and instrument usage. Results: Low and high glucose critical limits (median values of 50 and 450 mg/dL, respectively) were the most frequently listed, reported by 73 hospitals (17.5%). Troponin was listed by ten hospitals, specified as troponin (n = 4), troponin I (n = 5), or “troponin TnI” (n = 1). Rarely, we encountered notification lists that assigned different critical limits to different instruments measuring the same analyte. Fifty-five hospitals did not specify instrument usage for any measurand on their notification list. The median differences in matched pairs of laboratory versus POC critical limits differed significantly (Wilcoxon signed-rank, P< 0.05) for low and high ionized calcium (N=21), low hemoglobin (N=23) and high INR critical limits for adults (N=27) and newborns (N=10). In some cases, matched pair analytes demonstrated identical critical limits. Conclusions: Harmonizing critical limit notification thresholds across point-of-care testing and different devices may improve consistency in clinical decision-making and patient outcomes. Despite the potential of POCT to shorten time to urgent intervention, relatively few hospitals currently include POCT critical limits on notification lists. Broader inclusion and transparent sharing of POCT critical values could harmonize practices across institutions, facilitate inter-institutional collaboration, and promote more timely and reliable responses to life-threatening diagnostic results.

Abstract: Vitamin B12 is an essential water-soluble vitamin required for critical biological processes such as DNA synthesis, erythrocyte maturation, and maintenance of nervous system integrity. Deficiency of vitamin B12 can lead to serious clinical outcomes, including megaloblastic anemia, and potentially irreversible neurological damage. Conversely, hypercobalaminemia may be associated with severe disorders, including solid neoplasms, hematological malignancies and, in some cases, may result from inappropriate supplementation or immunoglobulin–B12 macro-complexes. Although current guidelines recommend total serum vitamin B12 and holotranscobalamin (holoTC) as first-line biomarkers, total serum vitamin B12 remains the most widely used test in routine clinical practice. However, since holoTC represents the biologically active fraction of vitamin B12 available for receptor-mediated cellular uptake, it appears to provide a more reliable assessment of cobalamin status, particularly in specific clinical contexts. Compared with total vitamin B12 measurement, holoTC is assessed using a more limited number of analytical methods and the majority of available kit are aligned with the WHO reference standard, thereby improving inter-assay harmonization. This review explores literature data about the role of vitamin B12 and holoTC, discussing analytical challenges and clinical interpretation, highlights the potential advantages of holoTC over total serum B12.

Abstract: Although oral leukoplakia (OL) is recognized as a precancerous lesion, only a proportion of cases undergo malignant transformation (7,2 % to 9.5%). That's why recently, increasing attention has been directed toward molecular biomarkers that may better reflect the biological behaviour of OL Infiltration density of T and B lymphocytes, macrophages, plasma cells were assessed semi-quantitatively using a 4-point scale adapted from Nankivel study. CD9 antigen was assessed in epithelial and immune cells by counting them in three 400x fields. CD138 and CD68 biomarkers were associated with significantly elevated expression across both clinical types of OL where dysplasia was diagnosed. The increase in infiltration density with CD3 and CD20 labelled lymphocytes was statistically reliably confirmed only in non-homogeneous OL with dysplasia. CD9, as a protein reflecting the exosome compartments, revealed the interaction between the epithelium and immune cells. A moderate, statistically significant positive correlation was found only in leukoplakia with dysplasia between CD9+ immune cell levels and the number of epithelial layers expressing this antigen. Assessment of combinations of CD3, CD9, CD20, CD68, and CD138 biomarker expression, cons idering clinical type of leukoplakia, particularly non-homogeneous, appears to improve the accuracy of determining the risk of malignancy in individuals with oral dysplasia.

Abstract: Background and Objectives: Metaplastic breast carcinoma (MBC) is a rare, aggressive malignancy often resistant to conventional chemotherapy and characterized by a triple-negative phenotype. While immune checkpoint inhibition shows promise, the prognostic significance and distribution of programmed death-ligand 1 (PD-L1) expression within the heterogeneous architecture of MBC remain poorly understood. This study aimed to evaluate PD-L1 expression and the density of tumor-infiltrating lymphocytes (TILs) to clarify their roles in patient stratification and overall survival (OS). Materials and Methods: We retrospectively analyzed 48 MBC cases diagnosed between 2010 and 2025. PD-L1 expression was quantified using the Combined Positive Score (CPS) with the 22C3 antibody clone across diverse histological components. The density of stromal TILs density was assessed following internationally standardized guidelines. Clinical outcomes and clinicopathological parameters, including metastasis, lymphovascular invasion (LVI), and histological subtype were correlated with biomarker status using Kaplan-Meier survival analysis and Cox proportional hazards regression models. Results: PD-L1 positivity (CPS ≥1) was identified in 72.9/% of cases, one of the highest rates documented in literature. Notably, an inverse relationship was observed with PD-L1 negative tumors exhibited significantly higher rates of distant metastasis (46.2% vs. 17.1%; p=0.039). Multivariate analysis confirmed that low density of TILs (HR=9.66; p=0.016), metastasis (HR=4.40; p=0.023), and the presence of LVI (HR=3.84; p=0.047) were strong independent predictors of mortality. While PD-L1 status alone did not directly dictate overall survival, mean overall survival was markedly reduced in the low TILs cohort (32.2 months) compared to the high TILs group (114.2 months). Conclusion: The high prevalence of PD-L1 expression supports routine screening for immunotherapy eligibility in MBC. Our findings suggest that PD-L1 negative cases represent a high-risk biological subset driven by alternative immune evasion mechanisms. Integrating TILs density with conventional pathological parameters provides a more robust prognostic framework, enabling personalized therapeutic strategies for this challenging malignancy.

Abstract: Lipoblastomas are rare, rapidly growing benign tumors rising from embryonic white fatty cells that continue to proliferate in the postnatal period. We presented a case of a toddler with an undifferentiated myxoid neoplasm with features of a minimally differentiated lipoblastoma. Our patient was an 18-month-old female with a painless solid tumefaction in the middle third of the right leg. Histopathologically, the nodular tumor mass consisted of lipobastic cells embedded in a myxoid stroma. Immunohistochemistry showed strong diffuse positivity for vimentin, S100, CD34, CD56, NSE and rare Ki67+ cells. FOXO1 polyploidy was detected in 30% of cells by FISH. Using target RNA sequencing, we detected a fusion gene, CHCHD7-PLAG1, in the tumor sample. Sequence analysis showed that the first exons of CHCHD7 were fused to either exon 2 or exon 3 of PLAG1. Our case demonstrates that due to the histomorphologic overlaps, the molecular diagnostics is essential for confirmation of lipoblastomas.

Abstract: Background/Objectives: Conventional lymphatic invasion assessments may fail to identify lymph node metastasis (LNM) in breast cancer. We evaluated periarterial or perivenous invasion (periA/V), using Elastica–van Gieson (EVG)-stained sections, as a histological marker associated with LNM in invasive breast carcinoma of no special type (IBC-NST), focusing on the impact of invasive tumor size. Methods: We retrospectively analyzed 213 IBC-NST cases. PeriA/V was defined as tumor nests in direct contact with perivascular elastic fibers on EVG-stained sections. Diagnostic performance was compared with that of conventional LI markers (hematoxylin and eosin and D2-40), with stratified analyses by pathological T category (pT1 vs. pT2–4) and pT1 subcategories (pT1a, pT1b, and pT1c). Results: LNM was observed in 87 cases (40.8%). Overall, periA/V demonstrated high sensitivity (97.7%) and negative predictive value (NPV; 93.5%). In pT1 tumors (n = 130), periA/V achieved 100% sensitivity and 100% NPV (27/27), and was consistently present in all node-positive pT1b–c tumors. In multivariate analyses, periA/V remained independently associated with LNM in the pT1 group (odds ratio [OR]: 16.08, P = 0.003) and pT1c subgroup (OR: 14.7, P = 0.010). In pT2–4 tumors, periA/V became frequent regardless of nodal status, indicating reduced discriminatory value. Conclusions: EVG-based periA/V is a robust and highly sensitive surrogate marker for LNM in small IBC-NSTs. In pT1 tumors, periA/V negativity effectively ruled out nodal involvement. Incorporating periA/V assessment may provide a cost-effective and objective approach for nodal risk stratification in early-stage breast cancer.