Significance of clinical-immunological patterns and diagnostic yield of biopsies in microscopic polyangiitis and granulomatosis with polyangiitis.

BACKGROUND: Microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) are the two major antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). OBJECTIVES: To characterize a homogenous AAV cohort and to assess the impact of clinicopathological profiles and ANCA serotypes on clinical presentation and prognosis. Clinical differences in GPA patients according to ANCA serotype and the diagnostic yield for vasculitis of biopsies in different territories were also investigated. RESULTS: This retrospective study (2000-2021) included 152 patients with AAV (77 MPA/75 GPA). MPA patients (96.1% myeloperoxidase [MPO]-ANCA and 2.6% proteinase 3 [PR3]-ANCA) presented more often with weight loss, myalgia, renal involvement, interstitial lung disease (ILD), cutaneous purpura, and peripheral nerve involvement. Patients with GPA (44% PR3-ANCA, 33.3% MPO, and 22.7% negative/atypical ANCA) presented more commonly with ear, nose, and throat and eye/orbital manifestations, more relapses, and higher survival than patients with MPA. GPA was the only independent risk factor for relapse. Poor survival predictors were older age at diagnosis and peripheral nerve involvement. ANCA serotypes differentiated clinical features in a lesser degree than clinical phenotypes. A mean of 1.5 biopsies were performed in 93.4% of patients in different territories. Overall, vasculitis was identified in 80.3% (97.3% in MPA and 61.8% in GPA) of patients. CONCLUSIONS: The identification of GPA presentations associated with MPO-ANCA and awareness of risk factors for relapse and mortality are important to guide proper therapeutic strategies in AAV patients. Biopsies of different affected territories should be pursued in difficult-to-diagnose patients based on their significant diagnostic yield.

Restrospective reappraisal of the prognostic classification of spitzoid melanocytic neoplasms after BRAF and NRAS mutation characterisation: a single institution experience.

AIMS: The current WHO classification of melanocytic tumours excludes neoplasms showing BRAF or NRAS mutations from the Spitz category. This study aimed to review and reclassify atypical melanocytic tumours with spitzoid morphological features diagnosed between 2009 and 2021 in our hospital after expanding the molecular profile, including BRAF and NRAS mutations in all cases. METHODS AND RESULTS: A total of 71 neoplasms showing spitzoid features (Spitz-like) and atypia were included. The risk of progression of tumours was first studied by integrating the morphology, immunohistochemistry (p16, Ki67, HMB45 and PRAME) and fluorescence in-situ hybridisation (FISH) results (melanoma multiprobe and 9p21). In a second step, after expanding the molecular study, including BRAF and NRAS mutational status, the neoplasms were finally classified into four subgroups: atypical Spitz tumour (AST, n = 45); BRAF-mutated naevus/low-grade melanocytoma with spitzoid morphology (BAMS, n = 2); Spitz melanoma (SM, n = 14); and BRAF or NRAS mutated melanoma with spitzoid features (MSF, n = 10). Follow-up of patients revealed uneventful results for AST and BAMS. Only one SM presented lymph node metastasis after 134 months. Conversely, patients with MSF showed an unfavourable outcome: three developed lymph node metastases after a mean time of 22 months, with one patient presenting distant metastasis and dying of the disease 64 months from diagnosis. The progression-free survival showed significant differences between the four groups of spitzoid tumours (P < 0.001) and between both melanoma subtypes (P = 0.012). CONCLUSIONS: The classification and prognostication of atypical neoplasms with spitzoid features requires the integration of histomorphology with the molecular investigation of tumours, which should include BRAF and NRAS mutational status.

Combined WNT-activated deep-penetrating/plexiform melanocytoma: insights into clinicopathological and molecular characterization.

BACKGROUND: A combined deep-penetrating tumour redefined as WNT-activated deep-penetrating/plexiform melanocytoma (DPM), may pose challenging clinical and histological diagnoses. OBJECTIVES: To review the clinicopathological characteristics of combined DPMs and characterize the molecular profile of atypical and malignant forms. METHODS: The study included 51 patients with combined DPMs diagnosed at the Hospital Clinic of Barcelona and the University of Florence between 2012 and 2020. Clinical data, dermoscopy images (when available) and histological characteristics were reviewed. Immunohistochemistry for ß-catenin, LEF1, HMB45, Ki67, p16 and PRAME (preferentially expressed antigen in melanoma) was performed. Atypical forms underwent next-generation sequencing (NGS) panel analysis, including driver genes implicated in DPMs, TERT-promoter (p) mutations and the investigation of the 9p21 locus via fluorescence in situ hybridization. RESULTS: Among the 51 patients (32 females and 19 males, age range 4-74 years), 68% with available clinical data (15/22) were initially suspected of having melanoma. Except for one patient, complete excision resulted in no recurrences or metastases. One patient who had an incompletely excised combined DPM developed a lymph node melanoma metastasis 10 years later. In the 51 patients, 10 samples (20%) showed atypical histological features; 7 (14%) exhibited a significant loss of p16 expression; and 2 (4%) showed a high-proliferative index (Ki67 over 5%). NGS analysis in 11 patients revealed a double mutation BRAFV600E and exon 3 CTNNB1; no TERTp mutations were detected. CONCLUSIONS: Clinical suspicion of melanoma is common in combined DPMs, but malignant progression is infrequent in tumours lacking high-grade atypia or proliferation. These findings are congruent with the consideration of these lesions as intermediate-grade tumours or melanocytomas.

Antiphospholipase A2 receptor antibody-positive membranous nephropathy in the kidney donor: Lessons from a serendipitous transplantation.

Primary membranous nephropathy (PMN) is an autoimmune disease limited to the kidney that is characterized by the presence of circulating PLAR2 antibodies in 70% of the cases and usually positivity for PLA2R and IgG4 by immunohistochemistry (IHC) staining. We report the first documented case of PMN (PLA2R positive) in a deceased kidney donor, transplanted to two different recipients and their clinical and immunological evolution through serial biopsies. Recipient A's first allograft biopsy (Day 26) was compatible with a MN with both positive PLA2R and IgG4 subepithelial deposits in IHC. The donor's preimplantation kidney biopsies were retrieved and reexamined, revealing MN, with high intensity for PLA2R and IgG4 in IHC. Recipient B's protocol allograft biopsy, performed later at 3 months, also revealed histology compatible with MN but without the presence of PLA2R nor IgG4 in IHC. At 1-year follow-up, both recipients maintain graft function. Serial protocol biopsies were performed in both patients showing disappearance of IgG4 in recipient A but the persistence of PLA2R in IHC. We can conclude that, given the reversal of PMN changes in the grafts, it could be considered to transplant a patient from an asymptomatic deceased donor with PMN as long as he maintains unaltered renal function.

Overcoming limits: First ABO incompatible living donor paired kidney transplant in an hypersensitized pediatric recipient in Spain.

INTRODUCTION: HLA sensitization is a growing problem in children awaiting kidney transplantation. In some cases, finding an immunologically compatible donor entails contemplating the option of an ABO incompatible transplant or paired transplant. METHODS: Patient with genetic nephrotic syndrome and progressive chronic kidney disease, with a previous thrombosis of a first kidney transplant, resulting hypersensitized and remaining for a long-time on hemodialysis. Despite a desensitization strategy, family members were incompatible and deceased donation options must be ruled out due to the presentation of donor-specific antibodies (DSA). After 4 years, the possibility arises to perform a kidney paired transplant with a 62-year-old woman with an incompatible blood group. Although the current cytotoxicity- and cell-based crossmatches were negative, history of DSA were recorded. RESULTS: An intensive ABO and HLA desensitization protocol was performed in order to combat the isohemagglutinin antibodies and on the memory-HLA, based on rituximab, apheresis sessions, and immunoglobulins. Despite the donor being older in terms of pediatric transplantation, the donor-recipient weight difference, and immunological risk, the transplant was completed successfully. Maintenance of titration of up to 1/2 was confirmed after 3 weeks post-transplant (IgM and IgG). Kidney biopsy at 2 weeks and 6 months without signs of rejection. The patient is currently 12 months post-transplant and has not presented any signs of transplant rejection and has proper renal function. CONCLUSIONS: Kidney paired transplantation is an excellent solution for hypersensitized children, and ABO incompatibility can be considered to increase their options to find a good donor, without thereby obtaining worse results.

Immunophenotype of tumor-infiltrating lymphocytes in atypical Spitzoid tumors according to the risk of progression.

The aims of the study were to investigate and compare the immunophenotype of tumor-infiltrating lymphocytes (TILs) and PD-L1 expression in a series of benign, intermediate and malignant Spitzoid lesions showing marked inflammatory lymphoid component, to find out its possible relation with the prognosis of these lesions. Six out of 97 Spitz nevus (SN) (6 %), five out of 26 atypical Spitz tumors (AST) (16 %) and seven out of 37 Spitzoid melanomas (SM) (19 %) showed diffuse, intense inflammatory component and were included in the study. The biological risk of the tumors was assessed in all AST through the melanoma 4 probe-FISH assay and the 9p21 locus exploration. TILs were quantitatively immunophenotyped using CD3, CD4, CD8, CD20, TIA1, FOXP3 and PD1 antibodies. PD-L1 was assessed in tumoral cells and inflammatory cells adjacent to the tumor. No significant differences of TILs immunophenotype were found between SN, AST and SM. However, the classification of tumors according to the biological risk showed that grouped SN plus low-risk AST had a significantly higher number of T-cells CD8+ and TIA-1+, as well as a lower CD4/CD8 relation and B- lymphocyte number than high-risk of progression tumors (grouped high-risk AST plus SM). Immunoregulatory T-cell markers PD1 and FOXP3 only correlated with each other and with PD-L1 expression. In conclusion, The TILs immunoprofile differences between low-risk and high-risk of progression Spitzoid tumors, especially regarding CD8 and the cytotoxic immune response, can add prognostic information about these challenging tumors and impact the clinical management of patients.

Complement as the enabler of carfilzomib-induced thrombotic microangiopathy.

Carfilzomib has been associated with the development of thrombotic microangiopathy (TMA) in relapsed/refractory multiple myeloma patients, a severe disease with no currently available aetiological treatment. We evaluated the potential role of terminal complement pathway in four patients with carfilzomib-induced TMA. Membrane attack complex (C5b-9) deposition on endothelial cells in culture exposed to plasma from patients during the acute phase of the disease suggests complement overactivation as a mechanism of potential endothelial damage in three out of four patients. If confirmed in larger cohorts, C5b-9 evaluation will allow early identification of patients who could benefit from complement blockade and treatment monitoring.

Clinicopathological, Genetic and Survival Advantages of Naevus-associated Melanomas: A Cohort Study.

Several studies have suggested that naevus-associated melanomas differ from de novo melanomas, being thinner and with less ulceration; however, the prognostic implication is unclear. The objective of this study was to describe clinicopathological, genetic and survival characteristics of de novo and naevus-associated melanomas in a cohort of primary invasive cutaneous melanomas over a 20-year period. Of the 2,227 patients included in the study, 509 (22.86%) had naevus-associated melanomas. Compared with patients with de novo melanoma, they were younger, with a fairer phototype and a higher naevus count, tumours were predominantly the superficial spreading subtype, American Joint Committee on Cancer stage I, located on the trunk, and there were fewer signs of invasiveness (thinner Breslow index, less ulceration, lower mitotic index and less satellitosis). Germline mutation-al status did not show any significant association. As determined through univariate analysis, overall surviv-al was significantly better in patients with naevus- associated melanoma (hazard ratio 0.64; 95% confidence interval 0.51-0.80, p < 0.001), but multivariate analysis did not support this prognostic indication (hazard ratio 0.94; 95% confidence interval 0.75-1.18, p < 0.606). Despite this, we conclude that naevus- associated and de novo melanomas should be considered as different subtypes of melanoma.

IgA Nephropathy Recurrence after Kidney Transplantation: Role of Recipient Age and Human Leukocyte Antigen-B Mismatch.

BACKGROUND: Recurrence of immunoglobulin (Ig)A nephropathy (rIgAN) is a growing cause of kidney allograft dysfunction. This study was aimed at investigating factors associated with rIgAN and the subsequent progression to end-stage renal disease (ESRD). METHODS: Retrospective study including consecutive patients with IgA nephropathy (IgAN) who received a kidney transplant in our center between 1992 and 2016 and had a renal biopsy by clinical indication. The date of detection of chronic kidney disease (CKD) 5 was used as renal outcome. RESULTS: Eighty-six kidney transplants were performed in patients with IgAN, 38 (44%) were from living donors (related n = 26). rIgAN was diagnosed in 23 allografts (27%). Renal function and proteinuria at the end of the follow-up period were worst in the rIgAN patients compared to those without rIgAN (2.2 vs. 1.4 mg/dL, p = 0.014, and 1.16 vs. 0.49 g/day, p = 0.005, respectively). Risk of rIgAN and progression to CKD 5 decreased with patient's age (hazard ratio [HR] 0.95, 95% CI 0.92-0.98, p = 0.002, and HR 0.97, 95% CI 0.83-0.97, p = 0.008 per year, respectively). Patients with rIgAN had a higher risk of progression to CKD 5 (HR 6.7, 95% CI 1.3-35.7, p = 0.025). Full donor-recipient mismatch in the human leukocyte antigen (HLA)-B loci decreased the risk of rIgAN (HR 0.22, 95% CI 0.06-0.76, p = 0.017). CONCLUSIONS: rIgAN was an independent risk factor for ESRD after renal allograft. Younger age increased the risk of rIgAN and CKD 5. Conversely, HLA-B mismatching was a potential protective factor for rIgAN of this glomerular disease.

Primary cutaneous vs secondary cutaneous follicular lymphomas: A comparative study focused on BCL2, CD10, and t(14;18) expression.

BACKGROUND: Primary cutaneous follicular center-cell lymphoma (PCFCL) is one of the most common types of cutaneous B-cell lymphoma. Differences in immunohistochemical expression of BCL2 and CD10 antigens along with the presence of t(14:18) translocation in neoplastic cells have been postulated as relevant clues in differentiating PCFCL from cutaneous lesions secondary to a systemic follicular lymphoma (SCFL). The aim of this study is to evaluate the significance and usefulness of these parameters in a large series of patients. METHODS: Patients with PCFCL and SCFL diagnosed at three university hospitals in Barcelona, from 2000 to 2015 were reviewed. Clinical, histopathological, immunophenotypical, genetic, and outcome parameters were analyzed. RESULTS: Eighty-one cases (59 PCFCL and 22 SCFL) were included. There were no significant differences between PCFCL and SCFL cases regarding clinical presentation, site of involvement, or predominant type of skin lesions. Most patients in both groups showed positivity for BCL2 and CD10, but strong expression of BCL2 and CD10 was associated with SCFL cases. Although more frequent in SCFL, a small proportion of PCFCL cases also showed the t(14:18) on FISH analysis. CONCLUSION: The intensity of BCL2 expression was found to be the single most valuable clue in differentiating PCFCL from SCFL cases on histopathological grounds.

In vivo intratumoral Epstein-Barr virus replication is associated with XBP1 activation and early-onset post-transplant lymphoproliferative disorders with prognostic implications.

Post-transplant lymphoproliferative disorders are life-threatening complications following hematopoietic or solid organ transplantation. They represent a spectrum of mostly EBV-driven lymphoplasmacytic proliferations. While the oncogenic effect of EBV is related to latent infection, lytic infection also has a role in lymphomagenesis. In vitro, EBV replication is linked to plasma cell differentiation and XBP1 activation, although this phenomenon has never been addressed in vivo. We analyzed for the first time latent and lytic intratumoral EBV infection in a series of 35 adult patients with a diagnosis of post-transplant lymphoproliferative disorder (26M/9F, median age 54 years). A complete EBV study was performed including the analysis of the latent EBER, latent membrane protein-11, and EBV nuclear antigens as well as the immediate-early BZLF1/ZEBRA and early BMRF1/EADE31 lytic genes. XBP1 activation was assessed by nuclear protein expression. EBV infection was observed in 28 (80%) cases being latency II and III the most frequently observed 22 (79%). Intratumoral EBV replication was detected in 17 (60%) cases. Among these, XBP1 activation was observed in 11/12 evaluable cases associated with strong cytoplasmic immunoglobulin expression consistent with plasma cell differentiation. Intriguingly, the combination of latency III infection and EBV replication identified a high-risk subgroup of patients with significantly shorter survival (overall survival at 1 year 18% vs 48%) and early-onset (median of 7 vs 26 months) post-transplant lymphoproliferative disorder. Moreover, these patients appear to be more heavily immunosuppressed, so they exhibit lower rates of rejection and graft vs host disease but higher rates of cytomegalovirus reactivation. In conclusion, EBV replication is associated with plasma cell differentiation and XBP1 activation with prognostic implications. Both latency III and lytic EBV infection are related to aggressive and early-onset post-transplant lymphoproliferative disorder. These results suggest that immunohistochemical study of latent and lytic EBV genes in the clinical practice may help to select higher-risk patients to new therapies including antiviral treatments.

p53 Immunohistochemistry Defines a Subset of Human Papillomavirus-Independent Penile Squamous Cell Carcinomas With Adverse Prognosis.

Penile squamous cell carcinoma (PSCC) is classified into 2 prognostically distinct types: human papillomavirus (HPV)-associated and HPV-independent. However, the impact of p53 status on prognosis remains controversial. We correlated HPV and p53 status with the prognosis of a large series of patients with PSCC. p53 was analyzed according to a recently described immunohistochemical (IHC) pattern-based framework that includes 2 normal and 4 abnormal patterns and closely correlates with TP53 mutational status. A total of 122 patients with surgically treated PSCC in 3 hospitals were included. Based on HPV in situ hybridization and p16 and p53 IHC, the tumors were classified into 3 subtypes: HPV-associated, HPV-independent/p53 normal, and HPV-independent/p53 abnormal. All patients were followed up for at least 22 months (median: 56.9 months). Thirty-six tumors (29%) were HPV-associated, 35 (29%) were HPV-independent/p53 normal, and 51 (42%) were HPV-independent/p53 abnormal. Disease-related deaths were observed in 3/36 (8%), 0/35 (0%) and 14/51 (27%) of the patients, respectively (P< 0.001). A total of 7/14 deaths in the latter group were patients with tumors showing p53 abnormal patterns not recognized in the classic p53 IHC interpretation (basal, null, and cytoplasmic). According to our multivariate analysis, HPV-independent/p53 abnormal tumors and advanced stage were associated with impaired disease-specific survival (hazard ratio = 23.4, 95% CI = 2.7-3095.3; P= 0.001 and 16.3, 95% CI = 1.8-2151.5; P= 0.008, respectively). In conclusion, compared with patients with HPV-associated and HPV-independent/p53-normal PSCC, patients with HPV-independent/p53 abnormal PSCC have worse clinical outcomes. p53 IHC results define 2 prognostic categories in HPV-independent PSCC: HPV-independent/p53-normal tumors as low-risk tumors, whereas HPV-independent/p53-abnormal tumors as aggressive neoplasms.

Factor B Inhibition with Iptacopan in Recurrent C3 Glomerulopathy Following Kidney Transplant: A Report of Two Cases.

C3 glomerulopathy is a rare disease caused by fluid phase dysregulation of the alternative complement pathway. Currently, treatment depends on clinical and histological severity and includes nephroprotection, unspecific immunosuppression, and terminal complement blockers (C5), without having an etiological treatment approved. C3 glomerulopathy has high recurrence rates after kidney transplantation with a high risk of graft loss. Fortunately, new molecules are being developed that specifically target the proximal alternative complement pathway, such as iptacopan, a factor B inhibitor that showed promising results in native kidneys and cases of transplant recurrence in a phase 2 clinical trial. We present 2 "real-world" cases of C3 glomerulopathy recurrence in kidney allografts treated with iptacopan, with initial excellent clinical response and safety profile, especially with early introduction. We also present follow-up biopsies that showed no C3 deposition during factor B inhibition. Our cases suggest that proximal blockade of the alternative complement pathway can be effective and safe in the treatment of C3 glomerulopathy recurrence in kidney transplantation, bringing other questions such as dual blockade (eg, in C3 and C5), the optimal patient profile to benefit from factor B inhibition or treatment duration and its potential use in other forms of membranoproliferative glomerulonephritis (eg, immune complex-mediated).

[Main Types of Cysts in Dermatopathology: Part 2]. / Principales tipos de quistes en dermatopatología: Parte 2.

This is the second article in a two-part series published in this journal, in which we examine the histopathological characteristics, as well as the differential diagnosis, of the main entities that present as cystic and pseudocystic structures in cutaneous biopsy. In this second article, we address ciliated cutaneous cysts, branchial cysts, Bartholin's cysts, omphalomesenteric cysts, thymic cysts, thyroglossal duct cysts, synovial cysts, and median raphe cysts, as well as mucocele, ganglion, and auricular and digital myxoid pseudocysts.

[Main Types of Cysts in Dermatopathology: Part 1]. / Principales tipos de quistes en dermatopatología: parte 1.

Cystic structures represent one of the most common findings in dermatopathology. These encompass both cystic tumors and pseudocysts resulting from the accumulation of certain substances, such as mucin. In a two-part series (of which this is the first part), we have reviewed the principal types of cysts and pseudocysts that may be observed in cutaneous biopsies, examining their histopathological features and primary differential diagnoses. This first part encompasses infundibular cysts, eruptive dermoid cysts, pigmented follicular cysts, pilonidal cysts, tricholemmal cysts, milium cysts, hybrid cysts, bronchogenic cysts, as well as steatocystoma, hydrocystoma, and comedones.

Gene-expression profiling and not immunophenotypic algorithms predicts prognosis in patients with diffuse large B-cell lymphoma treated with immunochemotherapy.

Diffuse large B-cell lymphomas (DLBCLs) can be divided into germinal-center B cell-like (GCB) and activated-B cell-like (ABC) subtypes by gene-expression profiling (GEP), with the latter showing a poorer outcome. Although this classification can be mimicked by different immunostaining algorithms, their reliability is the object of controversy. We constructed tissue microarrays with samples of 157 DLBCL patients homogeneously treated with immunochemotherapy to apply the following algorithms: Colomo (MUM1/IRF4, CD10, and BCL6 antigens), Hans (CD10, BCL6, and MUM1/IRF4), Muris (CD10 and MUM1/IRF4 plus BCL2), Choi (GCET1, MUM1/IRF4, CD10, FOXP1, and BCL6), and Tally (CD10, GCET1, MUM1/IRF4, FOXP1, and LMO2). GEP information was available in 62 cases. The proportion of misclassified cases by immunohistochemistry compared with GEP was higher when defining the GCB subset: 41%, 48%, 30%, 60%, and 40% for Colomo, Hans, Muris, Choi, and Tally, respectively. Whereas the GEP groups showed significantly different 5-year progression-free survival (76% vs 31% for GCB and activated DLBCL) and overall survival (80% vs 45%), none of the immunostaining algorithms was able to retain the prognostic impact of the groups (GCB vs non-GCB). In conclusion, stratification based on immunostaining algorithms should be used with caution in guiding therapy, even in clinical trials.