Cancer Antigen 125 Expression Enhances the Gemcitabine/Cisplatin-Resistant Tumor Microenvironment in Bladder Cancer.

Cancer antigen 125 (CA125) is one of the mucin family proteins and is a serum tumor marker for various tumors, such as ovarian cancer, endometrial cancer, pancreatic cancer, and bladder cancer. CA125 is used to distinguish between benign and malignant tumors, monitor the response to chemotherapy, and detect relapse after initial treatment. Recently, CA125 was reported to be involved in chemoresistance through the physical characteristics of mucin or by modifying the immune tumor-microenvironment. However, the relationship between CA125 expression and chemoresistance in bladder cancer is still unclear. In this study, the clinicopathologic features of bladder cancer with CA125 expression and the status of the tumor-microenvironment related to gemcitabine/cisplatin resistance were investigated using publicly available data sets (Cancer Genome Atlas Expression, GSE169455 data set) from the cBioPortal website, the National Center for Biotechnology Information website, and an in-house case collection of bladder cancer. The cases with CA125 expression had poorer disease-free and overall survival rates than those without CA125 expression. A mucinous area surrounding cancer cells was frequently detected in cases with CA125 expression (81%; 13/16 cases). CA125 expression was also related to the immunosuppressive tumor-microenvironment through the infiltration of immunosuppressive immune cells, such as regulatory T cells and M2 macrophages. These results suggest that the status of tumor-microenvironment associated with CA125 is involved in gemcitabine/cisplatin resistance in bladder cancer.

Comparison and Development of Immunohistochemical Diagnostic Criteria for Blastic Plasmacytoid Dendritic Cell Neoplasm.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy derived from the precursors of plasmacytoid dendritic cells. Diagnostic criteria for BPDCN have not been fully established. BPDCN is often diagnosed without other BPDCN markers than the 3 conventional markers (CD4, CD56, and CD123) in practice and case reports, although acute myeloid leukemia/myeloid sarcoma (AML/MS), which is always considered in the differential diagnosis of BPDCN, can express them. We reviewed published case reports on BPDCN and found that the diagnosis was made without any other BPDCN markers than the conventional markers in two-thirds of the cases. Next, 4 representative existing diagnostic criteria were applied to 284 cases of our cohort of BPDCN and mimics. The results differed in 20% (56/284) of the cases. The criterion based on the 3 conventional markers alone had a low concordance rate (80%-82%) with the other 3 criteria, which were almost concordant with each other. However, newly found minor limitations in these criteria prompted us to devise new diagnostic criterion for BPDCN composed of TCF4, CD123, TCL1, and lysozyme. We also revealed that CD123-positive AML/MS patients had a significantly poorer outcome than those with BPDCN and that 12% (24/205) of the cases were non-BPDCN even if all 3 conventional markers were positive, thus clarifying the risk of diagnosing BPDCN without more specific markers. In addition, histopathological features, such as the reticular pattern, which is not seen in BPDCN and suggests AML/MS, were also identified.

[A Case of Transverse Colon Cancer Associated with Lynch Syndrome with Excellent Response to Pembrolizumab].

A 47-year-old woman diagnosed with transverse colon cancer with liver, peritoneal, and lymph node metastases was admitted. Modified FOLFOX6(mFOLFOX6)regimen was given as a first line chemotherapy and was followed by pembrolizumab after 1 cycle of the mFOLFOX6, because microsatellite instability(MSI)test of the tumor showed high-frequency MSI. Because of the transverse colon obstruction after 2 cycles of pembrolizumab, she underwent right hemicolectomy. Histological examination of the resected specimen revealed no residual tumor cells in the primary tumor and reginal lymph nodes. Immunohistochemistry for mismatch repair proteins(IHC-MMR)showed loss of MSH2 and MSH6 expression. Genetic test identified a MSH2 pathogenic variant leading to the diagnosis of Lynch syndrome. The present case shows the importance of MSI test or IHC-MMR before the treatment of metastatic colorectal cancer.

Immunohistochemical staining patterns of p53 predict the mutational status of TP53 in oral epithelial dysplasia.

Next-generation sequencing of oral squamous cell carcinoma (OSCC) has revealed TP53 as the most frequently mutated gene in OSCC mutually exclusive with human papillomavirus infection. Oral epithelial dysplasia (OED) is defined as a precancerous lesion of OSCC by the current World Health Organization (WHO) classification; therefore, it is assumed that TP53 mutations occur in early precancerous conditions such as OED. Here, we conducted an integrated analysis of TP53, including whole coding sequencing of TP53, FISH analysis of the 17p13.1 locus, and immunohistochemical analysis for p53 (p53-IHC), in 40 OED cases. We detected 20 mutations in 16 (40%) OED cases, and four cases, each harbored two mutations. FISH analysis revealed six of 24 cases (25%) had a deletion on 17p13.1, and four cases had concurrent TP53 mutations and 17p13.1 deletion (2-hit). Also, the increased frequency of TP53 mutations in higher degrees of OED implies acquisition of the mutation is a major event toward OSCC. p53-IHC revealed that overall cases could be categorized into four patterns that correlate well with the mutational status of TP53. Especially, two patterns, broad p53 expression type (pattern HI) and p53 null type (pattern LS), strongly correlated with a missense mutation and nonsense mutation, respectively. Furthermore, seven of the 40 cases progressed to SCC, and six of these seven cases presented pattern HI or LS. Therefore, patterns HI and LS have a high risk for malignant transformation if excisional treatment is not performed irrespective of the dysplasia grade. Although the current WHO classification mainly focuses on morphological criteria for the diagnosis of OED, interobserver discrepancy appears in some instances of the OED diagnosis. Our immunohistochemical analysis supports a more accurate pathological diagnosis for OED in cases of low dysplastic changes or of differential diagnosis with non-dysplastic lesions.

LUBAC accelerates B-cell lymphomagenesis by conferring resistance to genotoxic stress on B cells.

The linear ubiquitin chain assembly complex (LUBAC) is a key regulator of NF-κB signaling. Activating single-nucleotide polymorphisms of HOIP, the catalytic subunit of LUBAC, are enriched in patients with activated B-cell-like (ABC) diffuse large B-cell lymphoma (DLBCL), and expression of HOIP, which parallels LUBAC activity, is elevated in ABC-DLBCL samples. Thus, to clarify the precise roles of LUBAC in lymphomagenesis, we generated a mouse model with augmented expression of HOIP in B cells. Interestingly, augmented HOIP expression facilitated DLBCL-like B-cell lymphomagenesis driven by MYD88-activating mutation. The developed lymphoma cells partly shared somatic gene mutations with human DLBCLs, with increased frequency of a typical AID mutation pattern. In vitro analysis revealed that HOIP overexpression protected B cells from DNA damage-induced cell death through NF-κB activation, and analysis of the human DLBCL database showed that expression of HOIP positively correlated with gene signatures representing regulation of apoptosis signaling, as well as NF-κB signaling. These results indicate that HOIP facilitates lymphomagenesis by preventing cell death and augmenting NF-κB signaling, leading to accumulation of AID-mediated mutations. Furthermore, a natural compound that specifically inhibits LUBAC was shown to suppress the tumor growth in a mouse transplantation model. Collectively, our data indicate that LUBAC is crucially involved in B-cell lymphomagenesis through protection against DNA damage-induced cell death and is a suitable therapeutic target for B-cell lymphomas.

ARID2 is a pomalidomide-dependent CRL4CRBN substrate in multiple myeloma cells.

The immunomodulatory drug (IMiD) thalidomide and its derivatives lenalidomide and pomalidomide are therapeutic agents used in the treatment of multiple myeloma. Although pomalidomide offers considerable clinical benefits to patients with lenalidomide-resistant multiple myeloma, the molecular mechanisms underlying its superior efficacy remain unclear. Here we show that ARID2, a component of the polybromo-associated BAF (PBAF) chromatin-remodeling complex, is a pomalidomide-induced neosubstrate of CRL4CRBN. BRD7, another subunit of PBAF, is critical for pomalidomide-induced ARID2 degradation. ARID2 is involved in transcriptional regulation of pomalidomide target genes including MYC. Pomalidomide is more effective than lenalidomide in degrading ARID2 and is capable of inhibiting MYC expression and proliferation in lenalidomide-resistant cell lines. Notably, ARID2 expression is associated with a poor prognosis and is higher in chemoresistant minimal residual disease (MRD) populations, and in patients with relapsed/refractory multiple myeloma. These findings suggest that ARID2 is a promising target for overcoming lenalidomide resistance in patients with multiple myeloma.

Idiopathic Plasmacytic Lymphadenopathy Forms an Independent Subtype of Idiopathic Multicentric Castleman Disease.

Idiopathic multicentric Castleman disease (iMCD) is a type of Castleman disease that is not related to KSHV/HHV8 infection. Currently, iMCD is classified into iMCD-TAFRO (thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly) and iMCD-NOS (not otherwise specified). The former has been established as a relatively homogeneous disease unit that has been recently re-defined, while the latter is considered to be a heterogeneous disease that could be further divided into several subtypes. In 1980, Mori et al. proposed the concept of idiopathic plasmacytic lymphadenopathy (IPL), a disease presenting with polyclonal hypergammaglobulinemia and a sheet-like proliferation of mature plasma cells in the lymph nodes. Some researchers consider IPL to be a part of iMCD-NOS, although it has not been clearly defined to date. This is the first paper to analyze iMCD-NOS clinicopathologically, to examine whether IPL forms a uniform disease unit in iMCD. Histologically, the IPL group showed prominent plasmacytosis and the hyperplasia of germinal centers, while the non-IPL group showed prominent vascularity. Clinically, the IPL group showed significant thrombocytosis and elevated serum IgG levels compared to the non-IPL group (p = 0.007, p < 0.001, respectively). Pleural effusion and ascites were less common in the IPL group (p < 0.001). The IPL group was more likely to have an indolent clinical course and a good response to the anti-IL-6 receptor antibody, while the non-IPL counterpart frequently required more aggressive medical interventions. Thus, the IPL group is a clinicopathologically uniform entity that forms an independent subtype of iMCD.

[A Case of Malignant Peripheral Nerve Sheath Tumor of the Anus Resected by Robot Assisted-APR].

An 81-year-old female visited a local hospital with complaints of anal pain. A tumor was found on the right side of her anus, and the histopathological diagnosis was a non-epithelial malignant tumor. Therefore, the patient was referred to our hospital. Result of imaging inspection revealed that the tumor had invaded the lower rectum, but had not distantly metastasized. Based on the findings of another biopsy, the patient was diagnosed with a malignant peripheral nerve sheath tumor (MPNST). Robot-assisted abdominoperineal resection(D1)was performed, and the lesion was resected without any pathological remnants. During the postoperative period, the patient developed perineal wound infection. Subsequently, the patient was discharged from the hospital on postoperative day 10. At the 6-month postoperative follow-up, no recurrence was noted. Most MPNSTs occur in the limbs, trunk, and neck. MPNST in the primary gastrointestinal tract or in the vicinity of the gastrointestinal tract is relatively rare, and in principle, combined resection of the intestinal tract is required for surgical treatment. Here, we report a case of MPNST that occurred near the anus and infiltrated to the lower rectum and was completely resected by robot-assisted abdominoperineal resection.

Fluorescent nanoparticle-mediated semiquantitative MYC protein expression analysis in morphologically diffuse large B-cell lymphoma.

The current World Health Organization (WHO) classification defines a new disease entity of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, making fluorescence in situ hybridization (FISH) screening for these genes mandatory. In addition, the prognostic significance of MYC expression was reported, with a cut-off value of 40%. However, interobserver discrepancies arise due to the heterogeneous intensity of MYC expression by immunohistochemistry. Moreover, a cut-off value of positivity for MYC protein in diffuse large B-cell lymphoma (DLBCL) varies among studies at present. Here, we applied a high-sensitivity semiquantitative immunohistochemical technique using fluorescent nanoparticles called phosphor-integrated dots (PID) to evaluate the MYC expression in 50 de novo DLBCL cases, and compared it with the conventional diaminobenzidine (DAB)-developing system. The high MYC expression detected by the PID-mediated system predicted poor overall survival in DLBCL patients. However, we found no prognostic value of MYC protein expression for any cut-off value by the DAB-developing system, even if the intensity was considered. These results indicate that the precise evaluation of MYC protein expression can clarify the prognostic values in DLBCL, irrespective of MYC rearrangement.

Abemaciclib, a CDK4/6 inhibitor, exerts preclinical activity against aggressive germinal center-derived B-cell lymphomas.

The revised WHO classification newly defined the entities "High-grade B-cell lymphoma with MYC and BCL2, and/or BCL6 rearrangements (HGBL-DH/TH)" and "HGBL, NOS." Standard immunochemotherapy for diffuse large B-cell lymphoma (DLBCL), R-CHOP, is insufficient for HGBL patients, and there are currently no optimized therapeutic regimens for HGBL. We previously reported that CCND3, which encodes cyclin D3, harbored high mutation rates in Burkitt lymphoma (BL), HGBL and a subset of DLBCL. Furthermore, the knockdown of cyclin D3 expression was toxic to germinal center (GC)-derived B-cell lymphomas. Thus, the fundamental function of cyclin D3 is important for the pathogenesis of GC-derived B-cell lymphoma. We herein used two structurally different CDK4/6 inhibitors, palbociclib and abemaciclib, and examined their suppressive effects on cell proliferation and their ability to induce apoptosis in various aggressive B-cell lymphoma cell lines. The results obtained demonstrated that abemaciclib more strongly suppressed cell proliferation and induced apoptosis in GC-derived B-cell lymphoma cell lines than the control, but only slightly inhibited those features in activated B-cell (ABC)-like DLBCL cell lines. Palbociclib exerted partial or incomplete effects compared with the control and the effect was intermediate between abemaciclib and the control. Moreover, the effects of abemaciclib appeared to depend on cyclin D3 expression levels based on the results of the expression analysis of primary aggressive B-cell lymphoma samples. Therefore, abemaciclib has potential as a therapeutic agent for aggressive GC-derived B-cell lymphomas.

Possible reversibility between epithelioid and sarcomatoid types of mesothelioma is independent of ERC/mesothelin expression.

BACKGROUND: Mesothelioma is histologically divided into three subgroups: epithelioid, sarcomatoid, and biphasic types. The epithelioid or sarcomatoid type is morphologically defined by polygonal or spindle-like forms of cells, respectively. The biphasic type consists of both components. It is not yet understood how histological differentiation of mesothelioma is regulated. ERC/mesothelin is expressed in most cases of the epithelioid type, but not in the sarcomatoid type of mesothelioma. Consequently, its expression is well correlated to the histological subtype. We hypothesized that ERC/mesothelin expression influences the histological differentiation of mesothelioma, and tested this hypothesis. METHODS: We performed studies using the overexpression or knockdown of ERC/mesothelin in mesothelioma cells to examine its effect on cellular morphology, growth kinetics, or migration/invasion activity, in vitro. We then transplanted ERC/mesothelin-overexpressing and control cells into the intraperitoneal space of mice. We examined the effect of ERC/mesothelin overexpression on mouse survival and tumor phenotype. RESULTS: In vitro cell culture manipulations of ERC/mesothelin expression did not affect cellular morphology or proliferation, although its overexpression enhanced cellular adhesion and the migration/invasion activity of mesothelioma cells. The survival rate of mice following intraperitoneal transplantation of ERC/mesothelin-overexpressing mesothelioma cells was significantly lower than that of mice with control cells. The histological evaluation of the tumors, however, did not show any morphological difference between two groups, and our hypothesis was not validated. Unexpectedly, both groups (ERC/mesothelin-overexpressing and control) of mesothelioma cells that were morphologically monophasic and spindle-like in vitro differentiated into a biphasic type consisting of polygonal and spindle-like components in the transplanted tumor, irrespective of ERC/mesothelin expression. CONCLUSIONS: These results suggested that the histological transition of mesothelioma between epithelioid and sarcomatoid types may be reversible and regulated not by ERC/mesothelin, but by other unknown mechanisms.

A novel germline BMPR1A variant (c.72_73delGA) in a Japanese family with hereditary mixed polyposis syndrome.

Hereditary mixed polyposis syndrome (HMPS) is a rare autosomal dominant disorder characterized by a mixture of typical and/or atypical juvenile polyps, adenomas and hyperplastic polyps, resulting in an increased risk of colorectal cancer. In HMPS, four different germline BMPR1A variants from five unrelated families have been reported. This study is the first to report HMPS within a Japanese family. The proband underwent repeated colonoscopic polypectomies over a 5-year period, since the age of 67. Histological examination of these resected polyps revealed adenomas, juvenile-like polyps and hyperplastic changes. Genetic testing was conducted to identify the causative genes for hereditary gastrointestinal cancer syndromes, including BMPR1A. We detected a germline variant, c.72_73delGA, in BMPR1A. The proband's elder brother, younger sister and nephew have also undergone repeated colonoscopic polypectomies at other clinics. His sister and nephew underwent genetic testing, and the same BMPR1A variant was identified.

Anaplastic large cell lymphoma with TP63 rearrangement: A dismal prognosis.

Anaplastic large cell lymphoma (ALCL) with TP63 rearrangement is a new entity and has the most dismal prognosis in all types of ALCL. This might be due to the resulting fusion protein having N-terminal truncated p63 with high oncogenic ability. Since this N-terminal domain has the function of tumor suppressor activity, the mechanism for high oncogenic capacity is thought to be the dominant negative function. Here, we report two ALCL cases with TP63 rearrangement that was each given too short a prognosis (Case 1 and 2: four and six months) in spite of intensive treatment. Immunohistochemically, p63 was highly expressed, and a sprit signal was detected using a TP63 break apart fluorescence in situ hybridization (FISH) in each case. Additionally, a poor prognostic marker of ALCL, all cytotoxic molecules (TIA-1, Granzyme B, and Perforin) were also expressed in almost all ALCL cells. Taken together, we suggest that not only the dominant negative function of N-truncated p63 but also the effect of cytotoxic molecules may influence the dismal prognosis of ALCL with TP63 rearrangement.

[Human parvovirus B19-induced hemophagocytic lymphohistiocytosis and myocarditis in an adult patient with hereditary spherocytosis].

Human parvovirus B19 (HPV-B19) causes hemophagocytic lymphohistiocytosis (HLH). Here we describe a 35-year-old female with hereditary spherocytosis (HS) who developed HLH due to HPV-B19 infection. Upon admission, she had high fever and diarrhea. Laboratory findings included severe pancytopenia and elevated serum triglyceride and ferritin levels. Moreover, high HPV-B19 levels in the peripheral blood and increased reactive lymphocytosis in the bone marrow led to a diagnosis of HLH due to HPV-B19 infection. With supportive therapy and a blood transfusion, HLH symptoms, including fever and myelosuppression, improved in 1 week. However, symptoms of heart failure (HF) suddenly developed, and an echocardiography revealed diffuse systolic dysfunction, suggesting viral myocarditis due to HPV-B19 infection. Conservative management with diuretics gradually improved HF symptoms over a period of 2 weeks. HPV-B19 infection in adult patients with HS rarely results in severe HLH, but conservative therapy may improve the symptoms. Nonetheless, a careful follow-up is required after HLH improves because viral myocarditis can develop, as was seen in our patient.

Evaluation of the effects of MCVAC conditioning regimen followed by autologous hematopoietic stem cell transplantation in patients with relapsed and refractory Hodgkin lymphoma: A single-institution retrospective study.

High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (HDC/ASCT) has been useful in relapsed or refractory classic Hodgkin lymphoma (RRcHL). Furthermore, a ranimustine, cytarabine, etoposide, and cyclophosphamide (MCVAC) conditioning regimen has been effective in diffuse large B-cell lymphoma. However, limited data are available regarding this conditioning regimen for cHL. In this study, we investigated the efficacy and toxicity of MCVAC for RRcHL. We retrospectively analyzed 10 patients with RRcHL who underwent ASCT preceded by the MCVAC conditioning regimen between January 2009 and December 2021 at our institution. A total of 10 patients (median [range] age, 36 [23-64] years), including 5 (50%) men and 5 (50%) women, were treated with the MCVAC regimen followed by ASCT. The median follow-up duration of the 10 patients was 25.0 months. The 36-month PFS and OS rates were 43.8% (95% CI, 11.9%-72.6%) and 64.0% (95% CI, 22.6%-87.5%), respectively. Two patients died because of treatment-related factors, and one patient died because of disease progression. Based on our findings, recognizing the risk factors for adverse events (AEs) associated with this treatment, MCVAC may be a valid treatment option for the management of RRcHL.

The significance of T-BET-positive CD8 T-cells with diminished CD5 expression in Kikuchi-Fujimoto disease.

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare condition characterized by benign localized lymphadenopathy and clinical symptoms such as fever, sore throat, odynophagia, and leukopenia. Though the etiology of KFD is unknown, this condition is similar to viral infection, including increased infiltration of activated plasmacytoid dendritic cells. KFD exhibits three histological phases that reflect its progression status: proliferative, necrotic, and xanthomatous lesions. The expression loss of pan T-cell markers, such as CD2, CD5, and CD7, of infiltrating T-cells is observed in KFD cases, complicating the distinction from T-cell lymphoma. However, reports on the loss of their expression in KFD have been limited. Furthermore, the precise population of the T-cell subset in KFD is still unclear. Here, we focused on surface markers and transcription factors for T-cell differentiation and analyzed them immunohistochemically in 46 KFD cases. We observed diminished CD5 expression of CD8-positive (CD5dim CD8+) T-cells in the proliferative lesion of KFD cases. Furthermore, these CD5dim CD8+ T-cells expressed T-BET, a master regulator of type 1 helper T-cells. The upregulation of T-BET and downregulation of CD5 in CD8+ T-cells causes dysregulated activation and proliferation of CD8+ T-cells, potentially contributing to the unique histopathological features of KFD. Recognizing the frequent infiltration of T-BET-positive CD5dim CD8+ T-cells in KFD is important for distinguishing it from mature T-cell lymphoma. Our findings suggest that the immune response in KFD shares similarities with viral infections and highlight the importance of characterizing T-BET-positive CD5dim CD8+ T-cell populations for understanding KFD pathogenesis.

Copy Number Analysis of 9p24.1 in Classic Hodgkin Lymphoma Arising in Immune Deficiency/Dysregulation.

A subset of patients with rheumatoid arthritis receiving methotrexate develop immune deficiencies and dysregulation-associated lymphoproliferative disorders. Patients with these disorders often exhibit spontaneous regression after MTX withdrawal; however, chemotherapeutic intervention is frequently required in patients with classic Hodgkin lymphoma arising in immune deficiency/dysregulation. In this study, we examined PD-L1 expression levels and 9p24.1 copy number alterations in 27 patients with classic Hodgkin lymphoma arising from immune deficiency/dysregulation. All patients demonstrated PD-L1 protein expression and harbored 9p24.1 copy number alterations on the tumor cells. When comparing clinicopathological data and associations with 9p24.1 copy number features, the copy gain group showed a significantly higher incidence of extranodal lesions and clinical stages than the amplification group. Notably, all cases in the amplification group had latency type II, while 6/8 (75%) in the copy gain group had latency type II, and 2/8 (25%) had latency type I. Thus, a subset of the copy-gain group demonstrated more extensive extranodal lesions and higher clinical stages. This finding speculates the presence of a genetically distinct subgroup within the group of patients who develop immune deficiencies and dysregulation-associated lymphoproliferative disorders, which may explain certain characteristic features.

Diagnostic challenges of the idiopathic plasmacytic lymphadenopathy (IPL) subtype of idiopathic multicentric Castleman disease (iMCD): Factors to differentiate from IgG4-related disease.

AIMS AND METHODS: Idiopathic multicentric Castleman disease (iMCD) is currently considered to be classified into three clinical subtypes, including idiopathic plasmacytic lymphadenopathy (IPL), thrombocytopaenia, anasarca, fever, reticulin fibrosis/renal dysfunction, organomegaly (TAFRO) and not otherwise specified (NOS). Among the three, iMCD-IPL closely mimics IgG4-related disease (IgG4-RD). In diagnosing IgG4-RD, it is sometimes challenging to distinguish iMCD-IPL patients that also meet the histological diagnostic criteria for IgG4-RD. In this study, we focused on the number of IgG4-positive cells in the lymph nodes and analysed the relationship with laboratory findings to distinguish iMCD-IPL from IgG4-RD. Thirty-nine patients with iMCD-IPL and 22 patients with IgG4-RD were included. RESULTS: Among the cases considered to be iMCD-IPL, 33.3% (13/39) cases also met the histological diagnostic criteria for IgG4-RD and serum IgG4 levels were not different between the two groups. However, the serum IgG4/IgG ratio was significantly higher in IgG4-RD, with a cut-off value of 19.0%. Additionally, a significant positive correlation between serum IgG levels and the number of IgG4-positive cells was observed in iMCD-IPL (p=0.001). The serum IgG cut-off value for distinguishing iMCD-IPL meeting histological criteria for IgG4-RD from other iMCD-IPL was 5381 mg/dL. CONCLUSIONS: iMCD-IPL cases with high serum IgG levels (>5000 mg/dL) were likely to meet the diagnostic criteria for IgG4-RD because of the numerous IgG4-positive cells observed. A combination of clinical presentations, laboratory values including the serum IgG4/IgG ratios and histological analysis is crucial for diagnosis of IgG4-RD and iMCD-IPL.

Application of fluorescence in situ hybridization in distinguishing acral melanoma in situ from acral junctional melanocytic nevus on the volar skin in Japanese patients.

Four-colored fluorescence in situ hybridization (FISH) is an ancillary diagnostic tool for melanoma. However, most studies that have investigated the usefulness of FISH primarily focused on advanced melanomas. The aim of the current study was to evaluate the effectiveness of FISH in distinguishing acral melanoma (AM) in situ from benign acral junctional nevus (AJN), two types of lesions that are difficult to differentiate via traditional clinical means. The authors investigated the usefulness of FISH in 91 acral melanocytic lesions, including 50 lesions with diagnostic discrepancies between dermoscopic and pathologic approaches or difficulty diagnosing between AM in situ and AJN, on the volar skin of Japanese patients. The authors classified the lesions based on the diagnosis of dermatologists and pathologists into four groups: (I) lesions with a unanimous diagnosis by dermatologists and pathologists as AM in situ or AJN (n = 41); (II) lesions with a unanimous diagnosis by dermatologists only as AM in situ or AJN (n = 21); (III) lesions with a unanimous diagnosis by pathologists only as AM in situ or AJN (n = 15); and (IV) all other lesions (n = 14). The dermatologists diagnosed the lesions by clinical and dermoscopic photographs alone, while the pathologists diagnosed the lesions by microscopy of hematoxylin and eosin-stained slides alone. In group I (AM in situ [n = 20] and AJN [n = 21]), four-colored FISH demonstrated 90% sensitivity and 81% specificity in distinguishing AM in situ from AJN. There was a significant correlation between the FISH results and the unanimous diagnoses by pathologists alone (p = 0.03) in group III. However, FISH results were not significantly correlated with the unanimous diagnoses by dermatologists alone (p = 0.33) in group II. In conclusion, the four-colored FISH probe kit was useful in distinguishing between AM in situ and AJN and may be an ancillary method when pathologists who are not experts of dermatopathology diagnose melanocytic lesions.

EBV-positive mucocutaneous ulcer arising in methotrexate-treated rheumatoid arthritis patients: a clinicopathological study of 12 cases with analysis of PD-L1 expression.

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a newly recognized disease entity characterized by EBV-positive atypical B-cell proliferation. EBVMCU is a localized self-limited disease that affects mucosa and skin, especially the oral cavity. EBVMCU develops in immunosuppressive patients, such as those with methotrexate (MTX)-administrated rheumatoid arthritis (RA). Here we clinicopathologically analyzed 12 EBVMCU patients in a single institution. All cases were administrated MTX for RA, and five cases occurred in the oral cavity. All cases except one had demonstrated spontaneous regression after withdrawal of the immunosuppressive agent. We found 4 of 5 cases in the oral cavity had preceding traumatic events in the same site within a week before the onset of EBVMCU. Although there is no detailed and large study that has analyzed the trigger of EBVMCU, a traumatic event would indeed be a significant trigger for EBVMCU in the oral cavity. The cases were histologically classified; six cases were diffuse large B-cell lymphoma-type, five were polymorphous-type, and one was Hodgkin-like lesion type due to morphological appearance and immunophenotype. The PD-L1 expression was also examined by two antibodies for PD-L1 (E1J2J and SP142). Both antibodies revealed identical results for PD-L1 expression, and three cases were positive for PD-L1. The application of SP142 for evaluating the immune status of lymphomagenesis has also been proposed. Nine of 12 cases were negative for PD-L1, which implies that most EBVMCU cases may be caused by an immunodeficiency, rather than an immune-evasion, mechanism. However, as three cases were positive for PD-L1, immune escape may underly the pathogenesis in a subset of EBVMCU cases.