Unveiling renal pathology's potential: exploring a rare subtype of amyloid - apolipoprotein CII amyloidosis in the youngest patient: a case report and literature review.

In this clinical case report, we present a rare subtype of amyloidosis, apolipoprotein CII (apo CII), which was diagnosed through a renal biopsy and subsequently confirmed by identifying the p.K41T mutation via germline DNA sequencing. Upon reviewing the literature, five patients exhibiting identical mutation were identified via renal biopsy, while an additional patient was diagnosed through biopsies of the fat pad and bone marrow. Notably, our patient is the youngest recorded case. We pioneered the application of immunofluorescence and immunogold electron microscopy techniques for apo CII evaluation. Our report provides a detailed description of this case, supplemented by an extensive review encompassing apo CII, documented instances of apo CII amyloidosis with renal or systemic involvement, and potential underlying mechanisms.

Activation of Stimulator of IFN Genes (STING) Causes Proteinuria and Contributes to Glomerular Diseases.

BACKGROUND: The signaling molecule stimulator of IFN genes (STING) was identified as a crucial regulator of the DNA-sensing cyclic GMP-AMP synthase (cGAS)-STING pathway, and this signaling pathway regulates inflammation and energy homeostasis under conditions of obesity, kidney fibrosis, and AKI. However, the role of STING in causing CKD, including diabetic kidney disease (DKD) and Alport syndrome, is unknown. METHODS: To investigate whether STING activation contributes to the development and progression of glomerular diseases such as DKD and Alport syndrome, immortalized human and murine podocytes were differentiated for 14 days and treated with a STING-specific agonist. We used diabetic db/db mice, mice with experimental Alport syndrome, C57BL/6 mice, and STING knockout mice to assess the role of the STING signaling pathway in kidney failure. RESULTS: In vitro, murine and human podocytes express all of the components of the cGAS-STING pathway. In vivo, activation of STING renders C57BL/6 mice susceptible to albuminuria and podocyte loss. STING is activated at baseline in mice with experimental DKD and Alport syndrome. STING activation occurs in the glomerular but not the tubulointerstitial compartment in association with autophagic podocyte death in Alport syndrome mice and with apoptotic podocyte death in DKD mouse models. Genetic or pharmacologic inhibition of STING protects from progression of kidney disease in mice with DKD and Alport syndrome and increases lifespan in Alport syndrome mice. CONCLUSION: The activation of the STING pathway acts as a mediator of disease progression in DKD and Alport syndrome. Targeting STING may offer a therapeutic option to treat glomerular diseases of metabolic and nonmetabolic origin or prevent their development, progression, or both.

Amyloid Arthropathy: A Review.

Amyloid arthropathy is a joint disease associated with systemic amyloidosis. Herein, we present a model case and review the clinicopathologic features and pathophysiology of this disorder. Amyloid arthropathy results from elevation of serum amyloidogenic proteins and their deposition as aggregates in synovial fluid and articular tissues. The most common proteins are beta-2-microglobulin in the context of long-term hemodialysis therapy and immunoglobulin light chains associated with plasma cell proliferations. We provide a comprehensive update on the pathogenesis, clinical manifestations, and pathologic features of amyloid arthropathy. We provide detailed insights on amyloid protein deposition and aggregation in joints and proper details for diagnosis.

Don't SUMP it! Utility of PLAG1 immunocytochemistry in basaloid SUMP subcategory.

BACKGROUND: Basaloid salivary gland neoplasm of uncertain malignant potential (B-SUMP) is an indeterminate diagnostic subcategory, with pleomorphic adenoma (PA) representing the most common benign neoplasm. Pleomorphic adenoma gene 1 (PLAG1) staining is frequently seen in PAs and could aid in distinguishing them from other basaloid neoplasms. The authors evaluated the utility of PLAG1 immunocytochemistry (ICC) in differentiating PAs from other basaloid neoplasms in smears and liquid-based cytology (LBC) specimens. METHODS: In total, 45 B-SUMP cytology aspirates and corresponding surgical excision specimens were identified. PLAG1 immunostaining was performed in all aspirates and surgical excision specimens and was scored as positive (strong/diffuse), equivocal (focal/weak), or negative. RESULTS: PLAG1 ICC was performed directly on 38 smears and seven LBC specimens. PLAG1 was positive in 29 of 45 cases (64%), whereas six of 45 (13%) were equivocal, and 10 of 45 (22%) were negative. PLAG1-positive aspirates included 26 (90%) PAs, two (7%) basal cell adenomas (BCAs), and one (3%) carcinoma ex-PA. PLAG1-equivocal aspirates included four (67%) PAs and two (33%) BCAs, whereas negative aspirates included five (50%) BCAs, four (40%) adenoid cystic carcinomas, and one (10%) metastatic adenosquamous carcinoma. The sensitivity, specificity, positive, and negative predictive values were 87%, 86%, 93%, and 75%, respectively. Diagnostic accuracy was 87%. CONCLUSIONS: PLAG1 ICC is useful when positive (strong/diffuse) and can be reliably performed on smears and LBC specimens. PLAG1 was positive in most PAs and in a small subset of BCAs. Therefore, in the absence of atypical cytologic features, PLAG1-positive tumors could be diagnosed as benign, with a note favoring PA versus BCA. In contrast, PLAG1-negative/equivocal tumors should remain in the B-SUMP category.

Exploring the atypia of undetermined significance: Malignant ratio, ThyroSeq v3 positive call rate, molecular-derived risk of malignancy, and risk of malignancy as possible quality metric tools in thyroid cytology.

BACKGROUND: The atypia of undetermined significance (AUS) category is heterogeneous, leading to variations in its use. To prevent excessive usage, the AUS rate should be ≤10%. Although this recommendation aims to maintain diagnostic quality, it lacks supporting data. The AUS:Malignant (AUS:M) ratio has been proposed as a metric tool to evaluate AUS use. Furthermore, integrating ThyroSeq v3 (TSV3) positive call rate (PCR) and the molecular-derived risk of malignancy (MDROM) have been put forward as performance improvement tools. The authors reviewed their AUS:M ratios, TSV3 PCR, MDROM, and ROM. METHODS: Thyroid aspirates evaluated in the laboratory (from August 2022 to September 2023) by seven cytopathologists (CPs) were identified. AUS:M ratio, MDROM, ROM, and TSV3 PCR results for the laboratory and each CP were recorded and analyzed. RESULTS: A total of 2248 aspirates were identified (462 AUS and 80 malignant). The AUS:M ratio for the laboratory was 5.8 (CPs range, 2.8 to 7.3). The TSV3 PCR for the laboratory was 23% (CPs range, 11% to 41%). The MDROM for the laboratory was 19% (CPs range, 9% to 31%), whereas the ROM was 36% (CPs range, 29% to 50%). Linear regression analysis of AUS:M ratio versus TSV3 PCR and MDROM demonstrated a moderate positive correlation but a weak negative correlation to the ROM. Deviations from established targets were attributed to multiple factors. CONCLUSION: The findings of this study underscore the importance of using a combination of metrics to evaluate diagnostic practices. By dissecting the practice patterns of each CP, the authors can measure different aspects of their performance and provide individualized feedback.

Utility of the Milan System for Reporting Salivary Gland Cytopathology in fine needle aspiration cytology of minor salivary gland lesions.

INTRODUCTION: Salivary gland lesions are routinely evaluated by fine-needle aspiration cytology (FNAC) preoperatively. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) has standardized salivary gland FNAC reporting. Its application in major salivary glands (MSGs) has been well-established; however, its utility in minor salivary glands (MiSGs) is not well-known. We studied the utility of MSRSGC in MiSG FNAC. MATERIALS AND METHODS: A retrospective search of MiSG FNACs from 2 academic institutions (2006-2023) was performed. FNACs were classified using the MSRSGC. Histologic data were reviewed and recorded. The risk of malignancy (ROM), risk of neoplasia (RON), diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. RESULTS: The series included 43 MiSG FNAC (24 males and 18 females), with a mean age of 55 years (range 10-92). Aspirated sites included the following: palate, buccal space, floor of mouth, lip, tongue, and maxillary sinus. FNACs were classified as nondiagnostic (1), nonneoplastic (3), atypia of undetermined significance (6), benign neoplasm (9), salivary gland neoplasm of uncertain malignant potential (15), suspicious for malignancy, (2) and malignant (7). The risk of neoplasia and risk of malignancy were 87% and 39%. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 100%, respectively. CONCLUSIONS: Milan System for Reporting Salivary Gland Cytopathology offers valuable information for stratifying MiSG lesions. However, the distribution and the range of diagnostic entities encountered differ somewhat from those in MSGs. For instance, mucinous cyst contents may warrant unique consideration in MiSG; while an atypical classification is recommended in MSGs, the high prevalence of mucoceles in MiSG may tilt this group toward benignity.

Atypia of undetermined significance and ThyroSeq v3-positive call rates as quality control metrics for cytology laboratory performance.

BACKGROUND: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) recommends an upper limit of 10% for atypia of undetermined significance (AUS). Recent data suggest that this category might be overused when the rate of cases with molecular positive results is low. As a quality metric, the AUS and positive call rates for this facility's cytology laboratory and each cytopathologist (CP) were calculated. METHODS: A retrospective analysis of all thyroid cytology cases in a 4.5-year period was performed. Cases were stratified by TBSRTC, and molecular testing results were collected for indeterminate categories. The AUS rate was calculated for each CP and the laboratory. The molecular positive call rate (PCR) was calculated with and without the addition of currently negative to the positive results obtained from the ThyroSeq report. RESULTS: A total of 7535 cases were classified as nondiagnostic, 7.6%; benign, 69%; AUS, 17.5%; follicular neoplasm/suspicious for follicular neoplasm, 1.4%; suspicious for malignancy, 0.7%; and malignant, 3.8%. The AUS rate for each CP ranged from 9.9% to 36.8%. The overall PCR was 24% (range, 13%-35.6% per CP). When including cases with currently negative results, the PCR increased to 35.5% for the cytology laboratory (range, 13%-42.6% per CP). Comparison analysis indicates a combination of overcalling benign cases and, less frequently, undercalling of higher TBSRTC category cases. CONCLUSIONS: The AUS rate in the context of PCR is a useful metric to assess cytology laboratory and cytopathologists' performance. Continuous feedback on this metric could help improve the overall quality of reporting thyroid cytology.

Thymosin ß4 and its degradation product, Ac-SDKP, are novel reparative factors in renal fibrosis.

Previously, we found thymosin ß4 (Tß4) is upregulated in glomerulosclerosis and required for angiotensin II-induced expression of plasminogen activator inhibitor-1 (PAI-1) in glomerular endothelial cells. Tß4 has beneficial effects in dermal and corneal wound healing and heart disease, yet its effects in kidney disease are unknown. Here we studied renal fibrosis in wild-type and PAI-1 knockout mice following unilateral ureteral obstruction to explore the impact of Tß4 and its prolyl oligopeptidase tetrapeptide degradation product, N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), in renal fibrosis. Additionally, we explored interactions of Tß4 with PAI-1. Treatment with Ac-SDKP significantly decreased fibrosis in both wild-type and PAI-1 knockout mice, as observed by decreased collagen and fibronectin deposition, fewer myofibroblasts and macrophages, and suppressed profibrotic factors. In contrast, Tß4 plus a prolyl oligopeptidase inhibitor significantly increased fibrosis in wild-type mice. Tß4 alone also promoted repair and reduced late fibrosis in wild-type mice. Importantly, both profibrotic effects of Tß4 plus the prolyl oligopeptidase inhibitor, and late reparative effects of Tß4 alone, were absent in PAI-1 knockout mice. Thus, Tß4 combined with prolyl oligopeptidase inhibition is consistently profibrotic, but by itself has antifibrotic effects in late-stage fibrosis, while Ac-SDKP has consistent antifibrotic effects in both early and late stages of kidney injury. These effects of Tß4 are dependent on PAI-1.

Utility of high-risk HPV RNA chromogenic in situ hybridization in cytology smears and liquid-based preparations from metastatic head and neck squamous cell carcinoma.

BACKGROUND: High-risk human papillomavirus (HR-HPV) status is critical for the diagnosis, prognosis, and treatment of patients with oropharyngeal squamous cell carcinoma (OPSCC). Patients often present with enlarged cervical nodes, and fine-needle aspiration cytology (FNAC) is frequently the initial diagnostic procedure. Although p16 is the most widely used surrogate marker, problems with interpretation can limit its utility in FNAC. HR-HPV RNA in situ hybridization (ISH) has emerged as a specific way to assess HPV status on cell block preparations of cervical nodes. The authors evaluated the utility of HR-HPV ISH in conventional smears and liquid-based cytology (LBC) preparations of metastatic head and neck squamous cell carcinoma (SCC). METHODS: Thirty-one aspirates of proven, HPV-related SCC (confirmed by p16 and/or HR-HPV ISH in corresponding surgical specimens) were selected. Ten aspirates of HPV-negative SCC were also retrieved. HR-HPV ISH was performed on 27 smears and 14 LBC preparations. All results were scored as positive, equivocal, or negative. RESULTS: Eighty-four percent of metastatic, HPV-related SCCs were positive for HR-HPV RNA ISH, with high number of signals (n = 19) and low number of signals (n = 7), whereas five HPV-related SCCs were equivocal. All metastatic, HPV-negative SCCs were negative for HR-HPV ISH. CONCLUSIONS: HR-HPV ISH can be reliably performed on smears or LBC preparations, particularly when cell blocks are unavailable or paucicellular. Results were easy to interpret when high numbers of signals were present but were challenging in aspirates with low or rare number of signals. The current study suggests that HR-HPV ISH could be used as the initial testing modality for determining HPV status in FNAC specimens of metastatic SCC.

Utility of TRPS1 in Malignant Effusion Cytology.

INTRODUCTION: Identifying metastatic breast carcinoma (mBC) in malignant effusion cytology (MEC) specimens is critical, as this will determine the patient's prognosis and therapeutic management. Overlapping cytomorphologic features of breast carcinoma (BC) with other neoplastic entities makes the use of sensitive and specific markers highly desirable. Recent studies have reported trichorhinophalangeal syndrome type 1 (TRPS1) as a sensitive and specific marker for primary BC and mBC. We aimed to investigate TRPS1 expression in MEC of mBC and its most common diagnostic mimickers. MATERIALS AND METHODS: A retrospective search from the pathology archives identified 82 MEC. TRPS1 expression in mBC was analyzed, and the results were compared to those in metastatic carcinoma of Müllerian origin (mMC) and metastatic pulmonary adenocarcinoma (mPAC). TRPS1 immunoperoxidase was performed on cytospin or cell block preparations, and p < 0.05 was considered significant. RESULTS: Nuclear expression for TRPS1 was evaluated and scored as positive (≥1% of tumor cells) or negative. Nuclear TRPS1 expression was seen in 100% (30/30) mBC, 72% (18/25) mMC, and 7% (2/27) mPAC. This resulted in sensitivity, specificity, positive predictive value, and negative predictive values of 100%, 61%, 60%, and 100%, respectively. CONCLUSION: TRPS1 is a sensitive marker for mBC and can be reliably performed on cytology specimens. TRPS1 expression was also identified in a significant proportion of mMC, creating a potential diagnostic pitfall. Therefore, caution should be exercised when evaluating MEC of mBC with TRPS1. Consequently, a combination of immunoperoxidase panels should be employed in this setting.

Probability of malignancy and molecular alterations as determined by ThyroSeq v3 genomic classifier in Bethesda Category IV.

BACKGROUND: ThyroSeq molecular testing assesses the probability of malignancy (POM) in thyroid fine-needle aspiration cytology (FNAC) with indeterminate cytology. The aim was to investigate whether Bethesda category IV (BIV) subcategories are associated with specific molecular alterations, molecular-derived risk of malignancy (MDROM), and risk of malignancy (ROM). METHODS: FNAC slides, associated ThyroSeq, version 3, Genomic Classifier results, and surgical follow-up were retrieved for BIV nodules. Nodules were subcategorized as follicular neoplasm (FN) with or without cytologic atypia or oncocytic follicular neoplasm (OFN). The MDROM, ROM, and frequency of molecular alterations in FN and OFN were analyzed. p < .05 was considered significant. RESULTS: A total of 92 FNAC were identified and subcategorized into 46 FN (15 with and 31 without cytologic atypia) and 46 OFN. The benign call rate and the positive call rate were 49% and 51%, respectively. The MDROM in BIV was 34.3%, trending lower in OFN than in FN. RAS mutations were significantly more frequent in FN when compared to OFN (p = .02). Chromosomal copy number alterations were more often present in OFN than in FN (p < .01). On histologic follow-up, ROM in OFN was trending lower than in FN (p = .1). The most common diagnosis in OFN was oncocytic adenoma, whereas follicular variant papillary thyroid carcinoma was most common in FN. CONCLUSIONS: The MDROM and ROM were trending lower in OFN compared with FN, and the molecular alterations differed between OFN and FN subcategories.

Relationships among Non-Neoplastic Histopathological Features, Kidney Function, Proteinuria, and Other Clinical Factors in Patients Undergoing Nephrectomy.

Introduction: The non-neoplastic kidney parenchyma from nephrectomies is often overlooked in routine examinations. We aimed to evaluate the associations between global glomerulosclerosis (GS), interstitial fibrosis (IF), or arteriosclerosis (AS) and estimated glomerular filtration rate (eGFR), dipstick proteinuria, and other clinical factors. Methods: We performed a cross-sectional analysis of 781 patients with nephrectomy. We used regression models with and without interaction factors. The tested exposures were GS, IF, or AS, and the outcome measures were GFR and dipstick proteinuria. Results: In multivariable analyses, increasing degrees of GS, IF, or AS were significantly associated with lower eGFR and proteinuria (p < 0.05 for each). Obesity and hypertension (HTN) modified the association between eGFR and degrees of GS, whereas proteinuria and cardiovascular disease (CVD) modified the association between eGFR and degrees of AS (p for interaction <0.05). Compared with GS <10%, GS >50% was associated with lower eGFR in patients with (-45 mL/min/1.73 m2) than without (-19 mL/min/1.73 m2) obesity, and GS >50% was associated with lower eGFR in patients with (-31 mL/min/1.73 m2) than without (-16 mL/min/1.73 m2) HTN. Compared with AS <26%, AS >50% was associated with lower eGFR in patients with (-11 mL/min/1.73 m2) than without (-6 mL/min/1.73 m2) proteinuria, and AS >50% was associated with lower eGFR in patients with (-23 mL/min/1.73 m2) than without (-7 mL/min/1.73 m2) CVD. Conclusion: Greater degrees of each GS, IF, and AS are independently associated with proteinuria and lower eGFR. Obesity, HTN, proteinuria, and CVD modify the relationship between eGFR and specific histopathological features of nephrosclerosis.

Increased capillary branching contributes to angiotensin type 1 receptor blocker (ARB)-induced regression of sclerosis.

Chronic kidney disease is characterized by progressive glomerulosclerosis and tubulointerstitial fibrosis. High-dose angiotensin type 1 receptor blocker (ARB) or angiotensin-converting enzyme inhibitor can induce regression of existing glomerulosclerosis, at least in part by decreasing matrix accumulation. However, the potential mechanisms of remodeling of capillary loops remain obscure. This study aimed to determine whether capillary branching was augmented in glomeruli with ARB-induced regression of sclerosis. Three-dimensional confocal images were assessed by graph theory analysis to explore the topology of the glomerular capillary network. Compared with normal glomeruli, glomeruli of rats with progressive sclerosis were enlarged but had a significantly reduced number of capillary segments and capillary branch points and decreased complexity of the glomerular network. In contrast, in rats with regression of sclerosis induced by ARB, glomerular enlargement was due to a significantly increased number of glomerular capillary segments and capillary branch points and restored complexity of the capillary network. These data support the theory that capillary growth contributes to regression of sclerosis and is mediated at least in part by ARB-induced increased complexity and branching of capillary segments.

Protective effects of PPARγ agonist in acute nephrotic syndrome.

BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARγ) agonists have beneficial effects on renal structure and function in models of diabetes and chronic kidney diseases. However, the increased incidence of weight gain and edema potentially limits their usefulness. We studied an acute minimal-change disease-like nephrotic syndrome model to assess effects of PPARγ agonist on acute podocyte injury and effects on fluid homeostasis. METHODS: Acute podocyte injury and nephrotic syndrome were induced by puromycin aminonucleoside (PAN) injection in rats. RESULTS: PPARγ agonist, given at the time or after, but not before PAN, reduced proteinuria, restored synaptopodin, decreased desmin and trended to improve foot process effacement. There was no significant difference in glomerular filtration, effective circulating volume, blood pressure or fractional sodium excretion. PAN-injured podocytes had decreased PPARγ, less nephrin and α-actinin-4, more apoptosis and reduced phosphorylated Akt. In PAN-injured cultured podocytes, PPARγ agonist also reversed abnormalities only when given simultaneously or after injury. CONCLUSIONS: These results show that PPARγ agonist has protective effects on podocytes in acute nephrotic syndrome without deleterious effects on fluid homeostasis. PPARγ agonist-induced decrease in proteinuria in acute nephrotic syndrome is dependent at least partially on regulation of peroxisome proliferator-response element-sensitive gene expression such as α-actinin-4 and nephrin and the restoration of podocyte structure.

Macrophage polarization by angiotensin II-type 1 receptor aggravates renal injury-acceleration of atherosclerosis.

OBJECTIVE: Angiotensin II is a major determinant of atherosclerosis. Although macrophages are the most abundant cells in atherosclerotic plaques and express angiotensin II type 1 receptor (AT1), the pathophysiologic role of macrophage AT1 in atherogenesis remains uncertain. We examined the contribution of macrophage AT1 to accelerated atherosclerosis in an angiotensin II-responsive setting induced by uninephrectomy (UNx). METHODS AND RESULTS: AT1(-/-) or AT1(+/+) marrow from apolipoprotein E deficient (apoE(-/-)) mice was transplanted into recipient apoE(-/-) mice with subsequent UNx or sham operation: apoE(-/-)/AT1(+/+)→apoE(-/-)+sham; apoE(-/-)/AT1(+/+) →apoE(-/-)+UNx; apoE(-/-)/AT1(-/-)→apoE(-/-)+sham; apoE(-/-)/AT1(-/-)→apoE(-/-)+UNx. No differences in body weight, blood pressure, lipid profile, and serum creatinine were observed between the 2 UNx groups. ApoE(-/-)/AT1(+/+) →apoE(-/-)+UNx had significantly more atherosclerosis (16907±21473 versus 116071±8180 µm(2), P<0.05). By contrast, loss of macrophage AT1 which reduced local AT1 expression, prevented any effect of UNx on atherosclerosis (77174±9947 versus 75714±11333 µm(2), P=NS). Although UNx did not affect total macrophage content in the atheroma, lesions in apoE(-/-)/AT1(-/-)→apoE(-/-)+UNx had fewer classically activated macrophage phenotype (M1) and more alternatively activated phenotype (M2). Further, UNx did not affect plaque necrosis or apoptosis in apoE(-/-)/AT1(-/-)→apoE(-/-) whereas it significantly increased both (by 2- and 6-fold, respectively) in apoE(-/-)/AT1(+/+) →apoE(-/-) mice. Instead, apoE(-/-)/AT1(-/-)→apoE(-/-) had 5-fold-increase in macrophage-associated apoptotic bodies, indicating enhanced efferocytosis. In vitro studies confirmed blunted susceptibility to apoptosis, especially in M2 macrophages, and a more efficient phagocytic function of AT1(-/-) macrophages versus AT1(+/+). CONCLUSIONS: AT1 receptor of bone marrow-derived macrophages worsens the extent and complexity of renal injury-induced atherosclerosis by shifting the macrophage phenotype to more M1 and less M2 through mechanisms that include increased apoptosis and impaired efferocytosis.

Cells derived from young bone marrow alleviate renal aging.

Bone marrow-derived stem cells may modulate renal injury, but the effects may depend on the age of the stem cells. Here we investigated whether bone marrow from young mice attenuates renal aging in old mice. We radiated female 12-mo-old 129SvJ mice and reconstituted them with bone marrow cells (BMC) from either 8-wk-old (young-to-old) or 12-mo-old (old-to-old) male mice. Transfer of young BMC resulted in markedly decreased deposition of collagen IV in the mesangium and less ß-galactosidase staining, an indicator of cell senescence. These changes paralleled reduced expression of plasminogen activator inhibitor-1 (PAI-1), PDGF-B (PDGF-B), the transdifferentiation marker fibroblast-specific protein-1 (FSP-1), and senescence-associated p16 and p21. Tubulointerstitial and glomerular cells derived from the transplanted BMC did not show ß-galactosidase activity, but after 6 mo, there were more FSP-1-expressing bone marrow-derived cells in old-to-old mice compared with young-to-old mice. Young-to-old mice also exhibited higher expression of the anti-aging gene Klotho and less phosphorylation of IGF-1 receptor ß. Taken together, these data suggest that young bone marrow-derived cells can alleviate renal aging in old mice. Direct parenchymal reconstitution by stem cells, paracrine effects from adjacent cells, and circulating anti-aging molecules may mediate the aging of the kidney.

Application of the Milan System for Reporting Salivary Gland Cytopathology: A Single Institutional Experience of 354 Cases with Cytologic-Histologic Correlation.

BACKGROUND: Evaluation of salivary gland lesions is routinely done preoperatively by fine-needle aspiration cytology (FNAC). The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC), with diagnostic categories I-VI, has been recommended to standardize the reporting of salivary gland lesions by FNAC. We aimed to reclassify archival salivary gland FNAC samples using MSRSGC, correlate the samples with surgical resections, and calculate the risk of malignancy (ROM) for each category. METHODS: A total of 354 salivary gland FNAC samples (2013-2018) were reviewed. All FNAC results were retrospectively classified according to the MSRSGC. All cases had surgical follow-up. Histology was used to calculate the ROM, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy. RESULTS: The 354 aspirates were classified as: nondiagnostic (ND) 17.0% (60), non-neoplastic (NN) 1.4% (5), atypia of undetermined significance (AUS) 11.0% (39), benign neoplasm (BN) 49.4% (175), salivary gland neoplasms of unknown malignant potential (SUMP) 10.7% (38), suspicious for malignancy (SM) 3.4% (12), and malignant (M) 7.1% (25). The ROM was as follows: ND 22%, NN 20%, AUS 15%, BN 2%, SUMP 53%, SM 75%, and M 96%. The diagnostic accuracy for separating benign versus malignant neoplasms was 96%. Cytologic-histologic correlation yielded a false-negative rate of 2.7%, false-positive rate of 10.5%, PPV of 89%, NPV of 97%, sensitivity of 87%, and specificity of 98%. CONCLUSION: MSRSGC helps standardize cytology reports, provides useful information for appropriate clinical management, and ensures the best care of patients with salivary gland lesions.

Utility of NR4A3 on FNA cytology smears and liquid-based preparations of salivary gland.

BACKGROUND: Fine-needle aspiration cytology (FNAC) is generally the initial sampling method for salivary gland neoplasms. The cytomorphologic features of acinic cell carcinoma (AciCC) of salivary gland can overlap with other neoplastic and nonneoplastic entities. AciCCs harbor a recurrent t(4;9) rearrangement with upregulation of nuclear receptor subfamily 4 group A member 3 (NR4A3). NR4A3 protein overexpression has been shown to be highly sensitive and specific for the diagnosis of AciCC in histologic specimens and cell block preparations. However, data on NR4A3 immunocytochemistry (ICC) on conventional smears or liquid-based cytology are limited. METHODS: The authors identified 18 FNAC of histologically proven AciCC cases between 2013 and 2019. FNAC samples of diagnostic mimickers were likewise retrieved and included in the study cohort for comparison. The NOR1/NR4A3 mouse monoclonal antibody was applied directly to FNAC slides using a standard ICC technique. RESULTS: The cohort included ethanol-fixed Papanicolaou-stained cytologic smears and liquid-based preparations from 18 AciCC, one secretory carcinoma, four mucoepidermoid carcinomas, four salivary duct carcinomas, five pleomorphic adenomas (PA), five Warthin tumors, five oncocytomas, one oncocytic hyperplasia, and five nonneoplastic salivary gland cases. Strong nuclear staining for NR4A3 was present in all AciCC, weak nuclear staining was present in one PA, and all other non-AciCC were negative (sensitivity, 100%; specificity, 97%). CONCLUSIONS: NR4A3 ICC can be used directly on FNAC conventional smears and liquid-based cytology to reliably distinguish AciCC from its mimickers. This marker may be useful in cases where a cell block preparation is unavailable or inadequate.

Anti-Phospholipase A2 Receptor in Nonlupus Patients with Membranous Nephropathy and Crescents.

Introduction: Anti-phospholipase A2 receptor (PLA2R) is detected in approximately 70% of biopsies of "primary" membranous nephropathy (MN). Crescents in MN in nonlupus patients suggest additional injury, such as antineutrophil cytoplasmic antibody (ANCA) or anti-glomerular basement membrane (anti-GBM)-associated glomerulonephritis and are postulated to reflect injury by a mechanism that unmasks cryptic epitopes leading to the second autoantibody. Methods: We studied PLA2R staining in nonlupus patients with MN and crescents. Native renal biopsies in 16 nonlupus patients with MN and crescents were stained for PLA2R. Results: The patients included 5 women and 11 men, with mean age 61 years and elevated serum creatinine (mean 4.68 mg/dL). Hematuria and proteinuria (mean 4.97 g/day) were documented in 13 patients. Two patients had positive serum anti-GBM antibody. Nine of 11 patients tested for ANCA were positive, with p-ANCA (n = 4), c-ANCA (n = 2), or both (n = 1), with 2 not specified. On average, 27% of glomeruli had crescents. One patient had an initial biopsy with MN, 4 years later had MN with crescent, and 7 years later had rebiopsy with persistent MN with crescents. One patient had ANCA-associated vasculitis, and 5 years later had MN and crescent. The remaining 14 patients had concurrent diagnoses of MN and crescents. PLA2R was positive in 5 cases, 3 with ANCA positivity, 2 with unknown ANCA status, and none with anti-GBM disease. The patient with initial MN preceding crescent was PLA2R positive; the patient with initial ANCA-associated vasculitis preceding MN was PLA2R negative. Conclusions: Most patients (64%) presented with concomitant MN and crescents, with rare occurrence of an initial disease process followed later by the second injury. PLA2R was positive in 31% of patients, suggesting most are secondary MN. Further study to determine the cryptic epitopes may shed light on the triggering mechanisms for these rare but unlikely coincidental glomerular injuries.