Staining Pattern Research Articles

Subcellular expression of CD30 in cutaneous mastocytosis-An important factor for targeted treatment.

The subcellular distribution of CD30 on mast cells and the presence of eosinophils in cutaneous mastocytosis require further investigation, especially as the cell surface expression of CD30 is critical for the therapeutic response of systemic mastocytosis to brentuximab vedotin. Investigation of 147 biopsy specimens from 143 patients with cutaneous mastocytosis for mast cell density and distribution, frequency of CD30 expression, CD30 staining patterns, and presence and distribution of eosinophils. Correlation with clinical patterns. Retrospective multicenter immunohistochemical study of CD30 expression, eosinophils and basic clinical data in cutaneous mastocytosis. CD30 expression was found in all samples (cut-off: ≥1%), whereby the staining was predominantly cytoplasmic in 99% of the samples. Additional membrane staining was detected in 62% of the samples. Surface expression of CD30 was more common in biopsy specimens with a high mast cell burden and in biopsy specimens with a higher CD30 expression rate. Eosinophils were admixed in 58% of the samples. Females and older patients showed a trend of a lower mast cell burden. Retrospective study on formalin-fixed and paraffin-embedded tissue without functional analysis. Most cases of cutaneous mastocytosis show cell surface expression of CD30 expression and is, therefore, in principle, accessible for therapy with antibodies against CD30, provided the overall situation of the patient warrants.

Cytological diagnosis of follicular dendritic cell sarcoma with a unique pattern of D2-40 immunoexpression.

Fine needle aspiration procedure is routinely used for cytological diagnosis of nodal or extra nodal lesions. Follicular dendritic cell sarcoma (FDCS) is a rare mesenchymal neoplasm arising from follicular dendritic cells of lymphoid follicles at nodal and extranodal sites. Multimodal therapies have emerged for FDCS, necessitating its accurate pathologic diagnosis with additional ancillary testing for directing clinical management. By immunohistochemical analysis, FDCS is positive for the complement receptors CD21, CD23, and CD35. In addition, D2-40 is reported to be highly sensitive for FDCS with a strong membranous pattern of expression. In this study, we present the cytological diagnosis of a case of FDCS in retroperitoneal lymph nodes with an emphasis on a unique staining pattern of D2-40 which showed a strong nuclear pattern in tumor cells comparable to the membranous pattern of D2-40 on the control tissue and other surgical cases of FDCS in our comparative study.

Immunohistochemical Localization of Fibroblast Activation Protein in Coronary Arteries with Different Forms of Atherosclerosis

Background: Fibroblast activation protein (FAP) is a cell surface glycoprotein expressed by myofibroblasts in areas of active tissue remodeling. It plays a potentially important role in cardiac remodeling, atherosclerotic plaque formation, and plaque rupture. Given the distinct pathophysiology and morphology of different forms of atherosclerosis, we analyzed FAP expression in human coronary vessels with no coronary artery disease, atherosclerotic plaques at different levels of progression, and other distinct forms of coronary disease in post bypass vein grafting and cardiac allograft vasculopathy after a heart transplant. Methods: Immunohistochemical staining with monoclonal F19 mouse anti-human FAP antibody was performed to identify FAP in human atherosclerotic plaques, coronary bypass atherosclerosis, and post-transplant arteriosclerosis. The presence and distribution of FAP in different types and stages of human atherosclerosis were compared. Results: There was no FAP staining in patients with no significant coronary disease. All different types of human atherosclerotic lesioning lesions showed the presence of FAP expression, with different staining patterns in advanced atherosclerotic plaque, vein graft atherosclerosis lesions, and arteriosclerosis after a heart transplant. Conclusions: These data suggest that FAP may be a potential diagnostic marker and target for interventions, not only in coronary atherosclerotic plaque, but also in other forms of coronary disease, which have distinct pathophysiologies and currently limited treatment options.

Immunohistochemical Expression of Immune Regulatory Proteins in Interface Dermatoses.

Cutaneous immune-related adverse events (irAEs) of immunotherapies, such as anti-programmed cell death protein-1 (PD-1), suggest that immune checkpoint factors may contribute to the pathobiology of lichenoid interface dermatitis in immunotherapy-naïve patients. Our study aimed to describe innate and adaptive immune markers via immunohistochemical (IHC) staining of lichenoid interface dermatoses. We studied the staining patterns of PD-L1, STING, IL-36 gamma, CD8, PD-1, and LAG-3 in five interface dermatoses: oral lichen planus (LP) (n = 10), cutaneous LP (n = 10), chronic cutaneous lupus erythematosus (CLE) (n = 11), erythema multiforme (EM) (n = 11), and toxic epidermal necrolysis (TEN) (n = 13), by immunohistochemistry (IHC) analysis. Expression was evaluated semi-quantitively according to the percentage of keratinocytes and dermal lymphocytes stained compared to keratinocytes and resident pericapillary lymphocytes in normal human skin. All interface dermatoses evaluated showed increased expression of PD-L1 on keratinocytes and LAG-3 in lymphocytes. STING was increased on the keratinocytes of most specimens. Expression of IL-36 gamma, in basal layer keratinocytes was more extensive in oral LP and cutaneous LP and varied in CLE, EM, and TEN. Lymphocytic infiltration expressing PD-1 was elevated in oral LP, cutaneous LP, and CLE. Current thinking is that interface dermatitis is the result of a cell-mediated immune reaction involving cytotoxic CD8+ T-cell-mediated apoptosis of keratinocytes. The findings of this study suggest that in addition to cell-mediated immunity, innate immune factors may contribute to pathobiology.

Comparison of MIB‐1‐Specific Membrane Staining in Hyalinising Trabecular Tumor Using Mainstream Automated Immunohistochemical Staining Platforms

ABSTRACTBackgroundMIB‐1, a monoclonal antibody against Ki‐67, exhibits specific membrane staining in the immunohistochemistry of hyalinising trabecular tumor (HTT). This specific staining pattern is crucial in diagnosing HTT. Although manual immunohistochemical staining remains the established method for MIB‐1 staining, this process is complicated, inconsistent, and prone to false negatives.MethodsThis study aimed to explore whether the classical reaction pattern can be replicated by utilizing the current mainstream automated immunohistochemical staining platforms. Furthermore, we examined the effect of different conditions on staining efficiency and their value in clinical diagnosis assistance.ResultsSpecimens obtained from eight and six cases of HTT and non‐HTT, respectively, from a single center were stained using the manual staining method and the Dako Autostainer Link 48 (AS48), Dako Omnis, Ventana BenchMark ULTRA, and Leica BOND‐III automated immunohistochemical staining platforms. The Autostainer Link 48 was found to be the most stable staining platform, while the BenchMark ULTRA with primary antibody incubation at room temperature (RT) and the Omnis platform with antigen retrieval at pH 9.0 were able to reproduce membrane‐positive staining for MIB‐1 in the HTT specimens.ConclusionsOur results offer crucial reference value for clinical diagnostic assistance.

Clinical relevance and frequency of cytoplasmic patterns observed in ANA-Hep-2: experience of Cairo University Hospitals.

Antinuclear antibodies (ANA) are the most common biomarkers observed in autoimmune diseases. Cytoplasmic staining patterns on ANA-Hep-2 are gaining recognition but with scanty information about their clinical and diagnostic role. The aim is to assess the frequency of cytoplasmic ANA patterns in autoimmune diseases, and to evaluate their possible associations with clinical diagnoses and autoantibodies. This observational cross-sectional study was conducted by examining and/or reviewing ANA by indirect immunofluorescence assay during a 13-month period. This was followed by testing the group of patients with a positive cytoplasmic staining pattern (n = 92) using the Microblot-Array ANA plus for the presence of 44 specific autoantibodies. Out of 2741 samples, 1791 (65.3%) tested negative, 845 (30.9%) tested positive nuclear staining patterns, 56 (2.0%) positive solitary cytoplasmic staining patterns, and 49 (1.8%) positive mixed nuclear and cytoplasmic patterns. Ninety-two cases (3.4% of the total cases) were analyzed using Microblot-Array ANA plus, with reticular as the most frequent cytoplasmic pattern, followed by dense fine speckled. The most frequently associated disease with reticular pattern was primary biliary cholangitis (28.9%), and the most frequently detected autoantibodies were against M2 (66.7%). The most frequently associated disease with dense fine speckled pattern was systemic lupus erythematosus (69.4%), and the most frequently detected autoantibodies were against nucleosome (57.7%) and ribosomal P0 (53.8%). This study highlights the significance of reporting cytoplasmic staining patterns and their importance in assessment of autoimmune diseases. Larger cohort studies on treatment naïve patients are recommended.

DNA-Binding Protein A Is Actively Secreted in a Calcium-and Inflammasome-Dependent Manner and Negatively Influences Tubular Cell Survival.

DNA-binding protein A (DbpA) belongs to the Y-box family of cold shock domain (CSD) proteins that bind RNA/DNA and exert intracellular functions in cell stress, proliferation, and differentiation. Given the pattern of DbpA staining in inflammatory glomerular diseases, without adherence to cell boundaries, we hypothesized extracellular protein occurrence and specific functions. Lipopolysaccharide and ionomycin induce DbpA expression and secretion from melanoma and mesangial cells. Unlike its homologue Y-box-binding protein 1 (YB-1), DbpA secretion requires inflammasome activation, as secretion is blocked upon the addition of a NOD-like receptor protein-3 (NLRP3) inhibitor. The addition of recombinant DbpA enhances melanoma cell proliferation, migration, and competes with tumor necrosis factor (TNF) binding to its receptor (TNFR1). In TNF-induced cell death assays, rDbpA initially blocks TNF-induced apoptosis, whereas at later time points (>24 h), cells are more prone to die. Given that CSD proteins YB-1 and DbpA fulfill the criteria of alarmins, we propose that their release signals an inherent danger to the host. Some data hint at an extracellular complex formation at a ratio of 10:1 (DbpA:YB-1) of both proteins.

Cross-sectional study to evaluate the utility of elastic tissue staining in primary cicatricial alopecia

Background and aimsDiagnosing end-stage primary cicatricial alopecia (PCA) on routine histology is challenging since the major diagnostic feature (inflammatory infiltrate) may be minimal or absent. This study aimed to assess...

Identification of DAGLA as an autoantibody target in cerebellar ataxia

BackgroundWe aimed to investigate the clinical, imaging and fluid biomarker characteristics in patients with antidiacylglycerol lipase alpha (DAGLA)-autoantibody-associated cerebellitis.MethodsSerum and cerebrospinal fliud (CSF) samples from four index patients were subjected...

Application of LEF-1 immunohistochemical staining in the diagnosis of solid pseudopapillary neoplasm of the pancreas

IntroductionSolid pseudopapillary neoplasm (SPN) is a tumor of young females with gain-of-function mutation in catenin beta 1 gene involved in Wnt signal transduction pathway. Beta-catenin immunohistochemistry (IHC) is used to diagnose SPN. Lymphoid enhancer-binding factor 1 (LEF-1) has been recognized in the transactivation of Wnt pathway. We aim to study LEF-1 IHC in SPN and other pancreatic tumors and compare it with beta-catenin IHC. MethodsWe retrieved cases of SPN, pancreatic neuroendocrine tumor (PanNET), serous cystadenoma (SCA), ductal adenocarcinoma (PDAC) and acinar cell carcinoma (ACC) from 2011 to 2023. Formalin-fixed, paraffin-embedded blocks with adequate tumor were cut and stained with beta-catenin (B-Catenin-1 clone) and LEF-1 (EP310 clone) IHC. Cases were reviewed by two pathologists independently. Nuclear staining with LEF-1 and beta-catenin was considered as positive. ResultsOur cohort consisted of 111 cases [SPN = 59 (42 resections, 11 FNA, 6 biopsies), PDAC = 24, PanNET = 22, SCA = 5, ACC = 1]. For SPN cases male to female ratio was1:8. Age ranged from 9 to 81 years (average: 32 years). Pancreatic tail was the most common location (47 %) followed by head (28 %), body (19 %) and neck (6 %). Tumor size ranged from 1.0 to 12.2 cm (average: 5 cm). Among the SPN cases 57/59 demonstrated strong nuclear LEF-1 staining. 2/49 cases were negative for LEF-1 (both pathologist in agreement). All SPN tumors demonstrated nuclear staining with beta-catenin. Among the non-SPN tumors, beta-catenin showed nuclear staining in 2/52 cases (2 PDAC). The remaining 50 cases were negative for nuclear beta-catenin and demonstrated variable staining pattern with interpretation variability between the two pathologists. The sensitivity and specificity for LEF-1 were 97 % and 100 %, respectively, while for beta-catenin, they were 100 % and 96 % respectively. ConclusionCrisp nuclear staining of LEF-1 without background staining makes diagnostic interpretation relatively easy and accurate compared to beta-catenin IHC. This is further helpful for small biopsy samples to help differentiate SPN from mimickers such as PanNET. None of the non-SPN cases displayed nuclear LEF-1 rendering it a valuable adjunct to beta-catenin in the diagnostic evaluation of SPN.

The Impact of Pre-biopsy Corticosteroids Use on CD20 Staining Pattern in B-cell Lymphomas

Abstract Introduction/Objective Diffuse large B-cell lymphomas, the most common Non-Hodgkin’s lymphoma are heterogeneous in terms of varied clinical presentation. The pathological work up these lymphomas is usually initiated with a CD20/CD3 immunohistochemical panel. Due to the aggressive nature of these lymphomas, pre-diagnosis corticosteroids are necessitated in some cases. However, the corticosteroids treatment can significantly alter the antigen staining of the lymphoma delaying the pathological diagnosis and subsequent treatment. This study investigates how pre-biopsy corticosteroids administration affects CD20 staining in B-cell lymphoma cells along with CD3 and PAX5, aiming to provide insights to the practicing pathologist for prompter diagnosis in these challenging cases. Methods/Case Report 14 biopsy cases of B-cell lymphoma pretreated with corticosteroids were included in this study. Clinicopathological parameters including corticosteroids usage are collected. H&E and immunohistochemistry slides were reviewed to analyze CD20, CD3 and PAX5 staining patterns. Results (if a Case Study enter NA) Of 14 cases, 10 cases showed cytoplasmic and granular staining with CD20, with extracellular spilling instead of the typical membranous pattern. This change was more frequent with intravenous dexamethasone (7/9) compared to oral prednisone (3/5), high dose (80%) compared to moderate and low dose (67%), short-term corticosteroids usage (86%) compared to intermediate-term and long-term (57%) usage and shorter dosing interval (100% in Q6H). The impact of prebiopsy corticosteroids was seen more on lymph node (5/7) compared to bone marrow (3/5). This cytoplasmic granularity was also observed in CD3 in the background non-neoplastic T lymphocytes in 25% of the cases. Though nuclear stains such as PAX5, Ki67, MUM1 and BCL6 also showed granularity in a significant number of cases, it was limited to the nucleus. Conclusion Pre-biopsy corticosteroids leads to alteration in CD20 staining pattern of the lymphoma cells leading to cytoplasmic granularity with extracellular spillage, which causes diagnostic challenge. This effect varies according to the type, route, dose, and duration of corticosteroids usage.

The Importance of Pathogenesis: A Molecular Investigation on A Solitary Choriocarcinoma Lung Lesion with No Primary Lesion

Abstract Introduction/Objective We present an exceedingly rare case of metastatic choriocarcinoma to the lung with no primary lesion. Notably, this is the only case where STR molecular studies have been conducted. Methods/Case Report A 43-year-old G1P1001 female with no past medical history presents with severe shortness of breath, left-sided back, and chest pain for severe shortness of breath, left sided back and chest pain. Patients pregnancy test was positive with a B-hCG of 17944 u/L. Transvaginal ultrasound was negative for IUP. CTAP showed no masses in the uterine cavity or ovaries. D-dimer was elevated at 623 ng/ml. However, CTA chest was negative for pulmonary emboli but revealed a RLL mass measuring 2.6 x 2.5 cm x 2.9 cm with lobulated areas suspicious for vascular structures and connection to the right pulmonary vein. Patient was treated with a complete right lower lobectomy. An endometrial biopsy was performed and was negative for malignancy with no significant findings. Grossly, the mass was well-circumscribe, hemorrhagic, and necrotic, measuring 3.5 cm. Microscopically, the malignant cells had highly pleomorphic and hyperchromatic nuclei. There were also multiple multinucleated cells and mitotic figures present. Some of the cells had nested architecture leading to us to suspect a pleomorphic lung adenocarcinoma with choriocarcinomatous differentiation. We performed IHC staining that demonstrated strong positivity of AE1/AE3, CK7, hCG and a high Ki-67 index. The neoplastic cells also had focal p63 and p40 positivity. Furthermore, TTF1 and SALL4 were both negative. This staining pattern as well as patient’s clinical history of no gynecological lesion, lead us to favor lung adenocarcinoma with choriocarcinomatous differentiation. However, due to the abundance of syncytiotrophoblastic and trophoblastic cells, metastatic choriocarcinoma could not be ruled out. Therefore, the case was sent out for external consultation and Short Tandem Repeat (STR) molecular testing. Surprisingly, the STR testing results showed some STR of paternal origin indicating a metastatic gestational choriocarcinoma. The patient’s surgery was highly successful and lead to a down trending of b-hCG from 17944 to 1768 after removal. Results (if a Case Study enter NA) NA Conclusion Performing STR testing was pivotal in this case as it revealed the presence of DNA of paternal origin, providing crucial evidence that the tumor was of gestational origin, guiding the diagnosis towards metastatic gestational choriocarcinoma.

Neodymium-Facilitated Visualization of Extreme Phosphate Accumulation in Fibroblast Filopodia: Implications for Intercellular and Cell–Matrix Interactions

A comprehensive understanding of intercellular and cell–matrix interactions is essential for advancing our knowledge of cell biology. Existing techniques, such as fluorescence microscopy and electron microscopy, face limitations in resolution and sample preparation. Supravital lanthanoid staining provides new opportunities for detailed visualization of cellular metabolism and intercellular interactions. This study aims to describe the structure, elemental chemical, and probable origin of zones of extreme lanthanoid (neodymium) accumulation that form during preparation for scanning electron microscopy (SEM) analysis in corneal fibroblasts filopodia. The results identified three morphological patterns of neodymium staining in fibroblast filopodia, each exhibiting asymmetric staining within a thin, sharp, and extremely bright barrier zone, located perpendicular to the filopodia axis. Semi-quantitative chemical analyses showed neodymium-labeled non-linear phosphorus distribution within filopodia, potentially indicating varying phosphate anion concentrations and extreme phosphate accumulation at a physical or physicochemical barrier. Phosphorus zones labeled with neodymium did not correspond to mitochondrial clusters. During apoptosis, the number of filopodia with extreme and asymmetric phosphorus accumulation increases. Supravital lanthanoid staining coupled with SEM allows detailed visualization of intercellular and cell–matrix interactions with high contrast and resolution. These results enhance our understanding of phosphate anion accumulation and transfer mechanisms in cells under normal conditions and during apoptosis.

ALK1-negative Epithelioid Histiocytoma

Abstract Introduction/Objective We present a case of epithelioid histiocytoma (EH). The epithelioid nature of this lesion imitates the appearance of neoplastic lesions such as melanocytic, dermatofibroma/histiocytoma, non-Langerhans histiocytosis such as reticulohistiocytoma, atypical fibroxanthoma, and rhabdomyosarcoma. Methods/Case Report Due to the unusual morphology and aberrant immunohistochemical staining pattern of this specific case, the sample was analyzed through Next Generation Sequencing (NGS), which showed the presence of a fusion of genes Sequestosome 1 (SQSTM1) and Anaplastic lymphoma kinas (ALK). SQSTM1 gene produces proteins involved in signal transduction pathways as well as autophagy, while ALK mainly serves the role of cellular communication and development. The most well-known ALK fusion partners include SQSTM and Vinculin (VCL), while there are other fusion partners that were more recently discovered such as Dynactin Subunit 1 (DCTN1) and ETS variant transcription factor 6 (ETV6). The spectrum of neoplasms produced through these fusions is wide as seen in lung adenocarcinoma and renal cell carcinoma (EML4-ALK), epithelioid histiocytoma (SQSTM1-ALK and VCL- ALK), pediatric renal cell carcinoma (VCL-ALK) among others. Results (if a Case Study enter NA) NA Conclusion We hope this case is a helpful addition to the literature to further aid diagnoses of future ALK fusion cases.

Exploring TFE3-Rearranged Renal Cell Carcinoma: A Case Study showing minimal expression of PAX-8

Abstract Introduction/Objective TFE3-rearranged renal cell carcinoma accounts for 1.6-4% of adult renal cell carcinomas (RCC). The histological characteristics of this entity can mimic many other renal cell neoplasms and definite diagnosis is based on immunohistochemical (IHC) and fluorescent in situ hybridization (FISH) analysis. Nonspecific IHC findings can lead to diagnostic challenges delaying confirmatory studies and underdiagnosis. Methods/Case Report A 28-year-old male with sickle cell disease and a right kidney multilocular cystic mass incidentally found during evaluation of splenomegaly underwent partial nephrectomy. The tumor showed papillary, alveolar and sheet-like growth patterns composed of eosinophilic to clear cells with pleomorphic nuclei, including multinucleate forms. Initial ancillary studies showed minimal neoplastic expression (less than 5%) of PAX-8. Repeat PAX-8 yielded similar results and laboratory controls were evaluated successfully. A full work-up showed positivity of AMACR (diffuse), CD10 (diffuse), Cathepsin K (patchy), CK7 (focal), CAIX (focal), and no significant expression of pancytokeratin, HMB-45, Melan-A and SMA. Fumarate hydratase was retained, and the tumor showed a non-specific staining pattern of S (2-succinyl)-cysteine. Controls were appropriate. A high suspicion for a TFE-rearranged RCC was maintained, and a final diagnosis was confirmed with FISH analysis demonstrating a TFE3 (Xp11.23) rearrangement. Results (if a Case Study enter NA) NA Conclusion Reports in the literature detail diffuse PAX-8 expression in TFE3-rearranged RCC. A high index of suspicion based on morphology in our case prompted FISH analysis leading to correct diagnosis. This case highlights the inconsistencies in the reported IHC profile of this entity. More studies are required to elaborate the presentations of this RCC subtype with numerous histologic mimics including the spectrum of immunostaining patterns to better assist patient care for this uncommon variant.

Calcifying Nested Stromal-Epithelial Tumor of the Liver: A Rare Find

Abstract Introduction/Objective Calcifying Nested Stromal-Epithelial Tumor (CNSET) is a rare tumor of the liver with less than 40 cases described in the literature. It is a low-grade tumor characterized by a distinctive nested architecture surrounded by a cellular myofibroblastic stroma and psammomatous calcifications. CTNNB1 gene deletions have been identified in several cases. CNSET typically arises in the right lobe and there is a female predominance with a predilection for children, adolescents, and young adults. Methods/Case Report We report an interesting case of CNSET in a 13-year-old male with no pertinent medical history who presented with a one-month history of fatigue, paleness, and liver mass on physical examination. MRI abdomen showed a 9.8 cm heterogenous mass with a central scar involving the right lobe of the liver, radiologically favored to be fibrolamellar hepatocellular carcinoma. AFP levels were normal. The patient underwent a partial hepatectomy. On gross examination, the specimen showed a yellow, circumscribed, firm mass. H&E slides showed scattered round to oval nests of bland spindle and epithelioid cells arranged in short fascicles at the periphery of nests. Collagenous stroma surrounding the nests showed spindle cells with tapered nuclei and pinpoint nucleolus. Areas with calcification and osseous metaplasia were also present. Immunohistochemistry performed showed the tumor cells to be positive for pan-cytokeratin (weak), WT-1, and vimentin, and negative for Hepar-1, arginase-1, synaptophysin, chromogranin, S100, NUT-1, myogenin, and desmin. Beta-catenin showed nuclear and cytoplasmic staining pattern. INI-1 was retained within the tumor cells and Ki-67 showed a proliferative index of approximately 10-20%. On MSK-Impact (next- generation sequencing), a mutation in CTNNB1 was detected. Archer FusionPlex was negative for gene fusions within the tumor. Results (if a Case Study enter NA) NA Conclusion It is crucial to become familiar with this rare entity and to avoid mistaking it for hepatoblastoma. CNSET exhibits a biphasic morphology characterized by a nested architecture featuring bland and uniform epithelioid and spindle cells, surrounded by a cellular myofibroblastic stroma. Confirming the diagnosis can be aided by nuclear β- catenin and the expression of WT1.

A Rare Case of Diffuse Large B Cell Lymphoma Co-occurring with Small Lymphocytic Leukemia: De Novo Process or Richter’s Syndrome?

Abstract Introduction/Objective Diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype of lymphoma and can arise either de novo or through transformation from indolent lymphomas, such as Chronic Lymphocytic Leukemia (CLL), known as Richter syndrome (RS). DLBCL derived from RS tends to exhibit more aggressive behavior compared to de novo DLBCL. Methods/Case Report We present a case of a 57-year-old female with no significant medical history, who initially presented with antibiotic and prednisone-resistant sinusitis, progressing to bilateral neck pain and eye congestion. Computed tomography (CT) imaging revealed a 3 cm mass in the right nasal cavity extending to the right maxillary sinus and medial right orbit. Histopathological examination showed diffuse sheets of intermediate to large cells with irregular nuclear contours, dispersed chromatin, variably conspicuous nucleoli, and moderate cytoplasm. Additionally, scattered foci of monotonous, atypical lymphoid cells with lower grade morphology, including small size and condensed chromatin, were also present. Immunohistochemical analysis revealed differential staining patterns between the two cell populations. The larger atypical cells expressed CD20, PAX5, CD10, BCL-6, MUM1, BCL-2, MYC, CD19 (dim), and exhibited a high Ki-67 proliferation index (>80%). In contrast, the smaller atypical cells were positive for CD5, CD19, CD20, PAX5, BCL-2, and CD23 (subset), with a lower Ki-67 proliferation index (<5%). Flow cytometry analysis of tissue samples revealed two distinct clones: Surface Kappa-restricted CD19 dim B cells (38.9%) with CD5- CD10 dim CD20+ and surface Lambda-restricted CD19+ B cells (58.7%) with CD5+ CD10- CD20+. FISH analysis revealed no gene rearrangements. The final diagnosis was Diffuse large B-cell lymphoma, germinal center B- cell phenotype, with aggressive features and focal involvement by small lymphocytic lymphoma/chronic lymphocytic leukemia. Results (if a Case Study enter NA) NA Conclusion The relationship between the large B-cell lymphoma and SLL/CLL remains uncertain; however, given the different immunophenotype and light chain expression observed by flow cytometry, they are likely to represent separate processes.

Immunohistochemical expression of PD-L1 in esophageal carcinoma and its correlation with histopathological features

Background: Carcinoma of the esophagus poses a considerable medical and public health challenge in many parts of the world. Despite advances in screening and multimodal management of this disease, overall survival remains poor. There is an utmost need to find a marker for the establishment of targeted immunotherapy. One immunohistochemical marker that has surfaced with the advent of anti-PDL1 immunotherapy is PD-L1 which has been proven to be advantageous. This study aimed to determine PD-L1 expression and its correlation with the grade of tumor and other histopathological parameters in 50 patients. Materials and Methods: A cross-sectional study was conducted on 50 cases of histopathologically proven esophageal carcinoma. Antibody used for PD-L1 was rabbit monoclonal (CAL10) Biocare. PD-L1 expression was considered positive when a complete or partial membranous or cytoplasmic staining pattern was noted in more than 5% of tumor cells. Correlation between PD-L1 expression and clinicopathological parameters was calculated. Proper consent was taken. The findings of the study were statistically analyzed using Statistical Package for the Social Sciences (SPSS) software version 21.0, a statistical program for Microsoft Windows. Results: This study revealed that PD-L1 positivity increases as the histopathological grade of esophageal squamous cells increases. Conclusions: The expression of PD-L1 increases with grade and shows more positive expression in poorly differentiated tumors. This indicates that PD-L1 overexpression is associated with aggressive disease. Targeted therapy against PD-L1 may prove to be beneficial in such patients.

A Case of Idiopathic Multicentric Castleman Disease Developing in a Patient with a History of Biopsy Proven Membranous Nephropathy

Abstract Introduction/Objective Idiopathic multicentric Castleman disease (iMCD) is a lymphoproliferative disorder involving two or more lymph node sites. It is usually associated with systemic inflammatory symptoms and organ dysfunction related to hypercytokinemia. Renal involvement in iMCD has only been described in a limited number of studies and case reports. Of note, only one previous case report has described results from renal biopsies taken prior to the development of iMCD. Methods/Case Report Our patient is a 43 year old female who was first diagnosed with membranous nephropathy in early 2020. She had PLA2 R negative and Exostosin-2 positive disease. Age appropriate screening for malignancy was unremarkable. She had positive ANA titres and normal complement levels but did not meet criteria for SLE per rheumatology. Her proteinuria was improved and maintained on Lisinopril for 3 years. In October 2023, her proteinuria suddenly increased. Repeat renal biopsy was unchanged from the initial biopsy. This time, she also noticed acute swelling over her subpectoral region. PET-CT scan revealed multiple areas of avid lymphadenopathy on either sides of the diaphragm but the highest yield PET- avidity was in the subpectoral region. Biopsy of the right subpectoral lymph node was performed. According to the WHO Classification, 5th edition, diagnostic criteria for iMCD-NOS was met with the histological features displaying grade 3 plasmacytosis, grade 2 regressed germinal centers, follicular dendritic cell prominence, increased hyperplastic follicles and increased vascularity. Immunohistochemical staining for CD138 highlighted abundant plasma cells, CD21 highlighted follicular dendritic cell prominence. Vascular proliferation was seen by CD34 staining. Kappa and Lambda- ISH demonstrated polytypic staining pattern and HHV-8 was negative. Results (if a Case Study enter NA) NA Conclusion There is a significant clinical, histologic and immunologic overlap between iMCD, autoimmune or infectious disorders and malignancy. HHV-8 negative/iMCD is less well understood and has no specific biomarkers. It is important to follow the available clinicopathologic diagnostic criteria for early diagnosis, follow up and treatment. Timely recognition can help prevent multiple organ system dysfunction, systemic inflammatory symptoms, cytopenias and polyclonal lymphoproliferation. Although the pathophysiology maybe unclear, this case may also suggest that in patients with a previously diagnosed membranous nephropathy, iMCD may play a role in recurrence and worsening of the disease.

Calretinin Staining Pattern is Variable in Hirschsprung Disease Occurring in Patients with Down Syndrome

Abstract Introduction/Objective Hirschsprung disease (HD), a congenital absence of enteric ganglion cells, affects 2-10% of patients with Down syndrome (DS). Submucosal nerve hypertrophy (SNH) and abnormal calretinin immunohistochemistry (IHC) support a diagnosis of HD, but the concordance of these findings can be variable in DS. Recognizing differences in HD occuring in DS can provide insight into the disease and help to improve outcomes and reduce delays in diagnosis for these patients. We sought to describe the histologic and calretinin staining patterns in HD occurring in patients with DS. Methods/Case Report From 2017-2023, 22 rectal biopsies from 20 patients with DS were retrospectively collected and reviewed. Subsequent pull-through (PT) resections were evaluated from 8 patients. Biopsies were evaluated for ganglion cells and SNH. Calretinin IHC was qualitatively evaluated for intensity (strong, weak) and density (many, partial, rare). Quantitative analysis used a calculation of the percent area above threshold (%AAT) function of the NIH ImageJ software version 2.1.0. Representative areas of the PT resections were also evaluated by ImageJ %AAT analysis. Results (if a Case Study enter NA) HD biopsies (12/22, 54.5%) were from male patients (age 3 days-6 weeks) and showed SNH in 11/12 (91.7%) with a mean nerve diameter of 57.3 microns (range 25-89 microns). Ganglionated biopsies (10/22, 45.5%) were collected from patients 3 days to 12 years old (M:F ratio 1:1.5) and showed SNH in 6/10 (60%) with a mean nerve diameter of 44.4 microns (range 10-70 microns). Strong normal calretinin staining was only seen in ganglionated biopsies (7/10 non-HD versus 0/12 HD). Negative calretinin staining was only seen in HD (0/10 non-HD vs 7/12 HD). Abnormal staining was seen in both non-HD (3/10, 30%) and HD (5/12, 41.7%) as partial strong positivity and rare weak positivity, respectively. ImageJ %AAT quantitative analysis revealed an average of 1.71 in biopsies with strong calretinin expression, 0.130 with weak staining, and 0.033 with negative staining. Evaluation of 8 PT resections (mean length of aganglionosis 7.1 cm) showed a mean nerve diameter in the aganglionic segment of 88.3 microns, 49.6 microns in the TZ, and 32.7 microns in the ganglionated segment. ImageJ %AAT quantitative analysis of calretinin revealed a mean of 0.044 in the aganglionic area, 0.66 in the TZ, and 1.56 in the ganglionated segment. Conclusion Recognition of the variable calretinin patterns seen in rectal biopsies from patients with DS can assist in accurate and timely diagnosis of HD.