Hybrid Oncocytic Tumors (HOTs) in Birt-Hogg-Dubé Syndrome Patients-A Tale of Two Cities: Sequencing Analysis Reveals Dual Lineage Markers Capturing the 2 Cellular Populations of HOT

Birt-Hogg-Dubé (BHD) syndrome is associated with an increased risk of multifocal renal tumors, including hybrid oncocytic tumor (HOT) and chromophobe renal cell carcinoma (chRCC). HOT exhibits heterogenous histologic features overlapping with chRCC and benign renal oncocytoma, posing challenges in diagnosis of HOT and renal tumor entities resembling HOT. In this study, we performed integrative analysis of bulk and single-cell RNA sequencing data from renal tumors and normal kidney tissues, and nominated candidate biomarkers of HOT, L1CAM, and LINC01187 , which are also lineage-specific markers labeling the principal cell and intercalated cell lineages of the distal nephron, respectively. Our findings indicate the principal cell lineage marker L1CAM and intercalated cell lineage marker LINC01187 to be expressed mutually exclusively in a unique checkered pattern in BHD-associated HOTs, and these 2 lineage markers collectively capture the 2 distinct tumor epithelial populations seen to co-exist morphologically in HOTs. We further confirmed that the unique checkered expression pattern of L1CAM and LINC01187 distinguished HOT from chRCC, renal oncocytoma, and other major and rare renal cell carcinoma subtypes. We also characterized the histopathologic features and immunophenotypic features of oncocytosis in the background kidney of patients with BHD, as well as the intertumor and intratumor heterogeneity seen within HOT. We suggest that L1CAM and LINC01187 can serve as stand-alone diagnostic markers or as a panel for the diagnosis of HOT. These lineage markers will inform future studies on the evolution and interaction between the 2 transcriptionally distinct tumor epithelial populations in such tumors.

Incidental Discovery of Hepatocellular Carcinoma on 18F-PSMA PET CT Performed for Prostate Cancer Reassessment

Prostate-specific membrane antigen positron emission tomography (PSMA PET) has been approved by the Food and Drug Administration (FDA) to identify prostate cancer in the setting of biochemical recurrence but can also identify other malignancies. 18F-PSMA PET has not been studied as a potential tool for hepatocellular carcinoma (HCC). We describe the case of a 76-year-old male with a rising prostate-specific antigen (PSA) after definitive prostate cancer treatment and no prior liver pathology who was incidentally found to have HCC on 18F-PSMA PET.

Kidney Biopsy Un-masquerading Plasma Cell Leukemia Diagnosed as Acute Myeloid Leukemia: An Unusual Clinical Experience

Plasma cell leukemia (PCL) is a rare aggressive variant of plasma cell myeloma. The differential diagnosis of PCL includes multiple myeloma (MM), other leukemias, and lymphomas with abnormal cells circulating in the peripheral blood. In addition, infectious or autoimmune diseases can cause reactive polyclonal plasmacytosis, which could confuse us with PCL occasionally. Sometimes, blastoid morphology can cause confusion in diagnosis, and immunohistochemistry is needed to differentiate PCL from other forms of leukemias and lymphomas. Here, we present a rare case of PCL diagnosed as acute myeloid leukemia (AML) with kidney biopsy establishing the correct diagnosis.

Adenovirus-Associated Acute Interstitial Nephritis With Graft Survival and Novel Follow-Up Biopsy Findings Including Karyomegaly: A Case Series

Adenoviral infections in post-transplant patients have been described in multiple organ systems, most classically the lung, liver, and alimentary tract. In the genitourinary tract, hemorrhagic cystitis is most frequently observed. Clinically apparent renal involvement with adenovirus is rare, and adenovirus-associated interstitial nephritis (AAIN) is an uncommon cause of renal allograft failure. Here, we present three cases of AAIN in patients who, after prompt diagnosis and treatment adjustment, experienced a return of allograft function. All patients were on standard triple therapy with tacrolimus levels within the target range at the time of biopsy. None of the patients had respiratory symptoms, and despite diarrhea, colon biopsies were negative. Only case one had positive adenovirus serology (IgG only) and case three had positive urine; two patients had leukopenia without neutropenia. Renal biopsies showed a characteristic granulomatous tubulocentric mixed lymphocytic and neutrophilic infiltrate. Adenovirus immunohistochemistry (IHC) showed strong staining in the tubular epithelium (nuclear and cytoplasmic) while staining for polyomavirus was negative. A follow-up biopsy two months after the diagnosis of AAIN in one patient revealed persistent cytopathic effects with negative adenoviral IHC staining while a biopsy at one year in another patient showed glomerular and tubulointerstitial scarring. AAIN is an uncommon but important etiology to consider in cases of acute renal allograft dysfunction. Although the presenting symptoms for AAIN are nonspecific, hematuria is frequently noted. Adenovirus IHC should be considered in cases with granulomatous inflammation associated with necrosis and mixed inflammatory infiltrate. As demonstrated in this single-institution case series, prompt diagnosis can result in the preservation of the renal allograft. Lasting cytopathic effects after adenoviral infection should also be considered in patients with a history, or potential history, of AAIN.

Sjögren's Syndrome Overlap With Lupus Nephritis: A Case Report and Literature Review of a Rare Entity

Overlap syndrome is a connective tissue disorder that satisfies the diagnostic criteria for at least two well-known autoimmune diseases. In this report, we describe a rare case of lupus overlap in an elderly woman with primary Sjögren's syndrome who presented with features of nephritic-nephrotic syndrome and renal biopsy results typical of lupus nephritis combined with multiple positive autoantibodies. The kidney biopsy results were assigned the highest weightage based on the revised 2019 systemic lupus erythematosus (SLE) classification criteria developed by the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR). The patient's condition significantly improved after appropriate immunosuppressive therapy was initiated. With the revised ACR/EULAR-2019 criteria, we anticipate that more SLE patients with typical lupus nephritis biopsy findings will be diagnosed accurately.

Localized Amyloidosis of the Sphenoid Sinus: A Case Report and a Descriptive Literature Review

Amyloidosis is the process of extracellular deposition of protein fibrils and manifests pathologically as a systemic or localized process. Localized amyloidosis of the head and neck is uncommon, and involvement of the sphenoid sinus is exceedingly rare. We describe a case of localized amyloidosis isolated from the sphenoid sinus. A descriptive literature search was conducted to highlight presentation, management, and outcomes related to this pathology. Our patient was a 65-year-old male who presented to our clinic with nasal congestion and an incidental finding of a large expansile mass within the sphenoid sinuses. The mass was seen to displace the pituitary gland, and thus a multidisciplinary care approach ensued. The mass was removed via a transnasal endoscopic approach. Pathology revealed fibrocollagenous tissue with calcifications that were positive on Congo red staining. The patient underwent further workup to rule out systemic involvement, which was unremarkable. Based on the findings of his workup, he was ultimately diagnosed with localized amyloidosis. A comprehensive review of the literature revealed 25 other reported cases of localized amyloidosis within the sinonasal region, with only one other case of isolated sphenoid sinus disease. Common presenting symptoms are nonspecific and may mimic other, more frequently seen regional pathologies, including nasal obstruction, rhinorrhea, and epistaxis. The treatment for localized disease is surgical resection. While localized amyloidosis within the sinonasal region is rare, it is important to recognize, work up, and treat it appropriately. A multidisciplinary team approach is necessary for appropriate diagnosis and management, and these patients should be followed closely after treatment.

Subarachnoid Hemorrhage in Autoimmune Vasculitis: A Rare Presentation of Systemic Lupus Erythematosus-Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis Overlap Syndrome

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) and systemic lupus erythematosus (SLE), though they share similar clinical characteristics, are distinguishable based on specific characteristics. The concomitant presentation of SLE and AAV as overlap syndrome is rare and makes the diagnosis challenging. Here, we describe a rare case of SLE and AAV overlaps presenting with hemorrhagic stroke as initial presentation, which has been reported only once before. The presence of several positive autoantibodies made the diagnosis challenging, but a kidney biopsy provided the definitive diagnosis and aided in initiating immunosuppressive therapy. The patient did not respond to standard initial surgical measures to lower elevated intracranial pressure and showed significant improvement to immunosuppressive therapy proving the temporal relationship. The authors of this case study aim to highlight the importance of considering SLE-AAV overlap in patients presenting with features similar to those described in the case report and intervening early, as delays in diagnosis can be fatal.

Brown-Norway chromosome 1 mitigates the upregulation of proinflammatory pathways in mTAL cells and subsequent age-related CKD in Dahl SS/JrHsdMcwi rats

Chronic kidney disease (CKD) has a strong genetic component; however, the underlying pathways are not well understood. Dahl salt-sensitive (SS)/Jr rats spontaneously develop CKD with age and are used to investigate the genetic determinants of CKD. However, there are currently several genetically diverse Dahl SS rats maintained at various institutions and the extent to which some exhibit age-related CKD is unclear. We assessed glomerulosclerosis (GS) and tubulointerstitial fibrosis (TIF) in 3- and 6-mo-old male and female SS/JrHsdMcwi, BN/NHsd/Mcwi [Brown-Norway (BN)], and consomic SS-Chr 1BN/Mcwi (SS.BN1) rats, in which chromosome 1 from the BN rat was introgressed into the genome of the SS/JrHsdMcwi rat. Rats were fed a 0.4% NaCl diet. GS (31 ± 3% vs. 7 ± 1%) and TIF (2.3 ± 0.2 vs. 0.5 ± 0.1) were significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi rats, and CKD was exacerbated in males. GS was minimal in 6- and 3-mo-old BN (3.9 ± 0.6% vs. 1.2 ± 0.4%) and SS.BN1 (2.4 ± 0.5% vs. 1.0 ± 0.3%) rats, and neither exhibited TIF. In SS/JrHsdMcwi and SS.BN1 rats, mean arterial blood pressure was significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi (162 ± 4 vs. 131 ± 2 mmHg) but not SS.BN1 (115 ± 2 vs. 116 ± 1 mmHg) rats. In 6-mo-old SS/JrHsdMcwi rats, blood pressure was significantly greater in females. RNA-sequencing analysis revealed that inflammatory pathways were upregulated in isolated medullary thick ascending tubules in 7-wk-old SS/JrHsdMcwi rats, before the development of tubule pathology, compared with SS.BN1 rats. In summary, SS/JrHsdMcwi rats exhibit robust age-related progression of medullary thick ascending limb abnormalities, CKD, and hypertension, and gene(s) on chromosome 1 have a major pathogenic role in such changes.NEW & NOTEWORTHY This study shows that the robust age-related progression of kidney disease in Dahl SS/JrHsdMcw rats maintained on a normal-salt diet is abolished in consomic SS.BN1 rats. Evidence that medullary thick ascending limb segments of SS/JrHsdMcw rats are structurally abnormal and enriched in proinflammatory pathways before the development of protein casts provides new insights into the pathogenesis of kidney disease in this model.

Novel Histopathologic and Ultrastructural Findings in Renal Allografts From Patients With Size and Age Mismatches: A Case Series

While reports on the long-term pathology in mismatched allografts have been focused on the donor and recipient body surface area, evidence is emerging to support donor-recipient age difference as an additional prognostic factor. Most reports are based on pediatric recipients receiving older/bigger allografts. Here, we describe three cases with age mismatch including two cases of adult patients receiving pediatric allografts and a third case of a younger patient receiving an allograft from an older donor exhibiting findings not described in extant literature. Each of these cases exhibits unique changes seen in mismatched donor-recipient size/age post-transplant pathology. These non-rejection changes should be suspected in cases of donor-recipient size/age mismatch. In cases of allograft function decline, a full biopsy workup, including electron microscopy, should be considered.

The rising incidence of ductal adenocarcinoma and intraductal carcinoma of the prostate: Diagnostic accuracy of biopsy, MRI-visibility, and outcomes

INTRODUCTION

Ductal adenocarcinoma (DA) and intraductal carcinoma (IDC) of the prostate are associated with higher stage disease at radical prostatectomy (RP). We evaluated diagnostic accuracy of biopsy, MRI-visibility, and outcomes for patients undergoing RP with DA/IDC histology compared to pure acinar adenocarcinoma (AA) of the prostate.

MATERIALS AND METHODS

A retrospective cohort study of men receiving RP between 2014 and 2021 revealing AA, DA, or IDC on final pathology was conducted. Multivariable logistic regression and Cox proportional hazards regression models were employed.

RESULTS

A total of 609 patients were included with 103 found to have DA/IDC. Patients with DA/IDC were older and had higher PSA, biopsy grade group (GG), RP GG, and other pathologic findings (extraprostatic extension, lymphovascular invasion, perineural invasion, pN stage) compared to AA patients (all P < 0.05). On multivariable analysis, higher age, RP GG, and pT3a were associated with DA/IDC on RP (all P < 0.05). Sensitivity and specificity of biopsy compared to RP for diagnosis of DA/IDC was 29.1% (16.7% DA, 27.8% IDC) and 96.6% (99.3% DA, 96.6% IDC), respectively. In a subset of 281 men receiving MRI, PI-RADS distribution was similar for patients with DA/IDC vs. AA (90.7% vs. 80.7% with PI-RADS 4-5 lesions, P = 0.23) with slightly higher biopsy sensitivity (41.9%). DA/IDC was associated with worse BCR (HR = 1.77, P = 0.02) but not biopsy DA/IDC (P = 0.90).

CONCLUSIONS

Sensitivity of prostate biopsy was low for detection of DA/IDC histology at RP. Patients with DA/IDC histology had unfavorable pathologic features at RP and worse BCR. Of patients with DA/IDC at RP, 90.7% were categorized as PI-RADS 4 to 5 on preoperative MRI.

Tissue biopsy for the diagnosis of amyloidosis: experience from some centres

A reliable diagnosis of amyloidosis is usually based on a tissue biopsy. With increasing options for specific treatments of the different amyloid diseases, an exact and valid diagnosis including determination of the biochemical fibril nature is imperative. Biopsy sites as well as amyloid typing principles vary and this paper describes methods employed at some laboratories specialised in amyloidosis in Europe, Japan and USA.

Benign tumors in TSC are amenable to treatment by GD3 CAR T cells in mice

Mutations underlying disease in tuberous sclerosis complex (TSC) give rise to tumors with biallelic mutations in TSC1 or TSC2 and hyperactive mammalian target of rapamycin complex 1 (mTORC1). Benign tumors might exhibit de novo expression of immunogens, targetable by immunotherapy. As tumors may rely on ganglioside D3 (GD3) expression for mTORC1 activation and growth, we compared GD3 expression in tissues from patients with TSC and controls. GD3 was overexpressed in affected tissues from patients with TSC and also in aging Tsc2+/^– mice. As GD3 overexpression was not accompanied by marked natural immune responses to the target molecule, we performed preclinical studies with GD3 chimeric antigen receptor (CAR) T cells. Polyfunctional CAR T cells were cytotoxic toward GD3-overexpressing targets. In mice challenged with Tsc2^–/– tumor cells, CAR T cells substantially and durably reduced the tumor burden, correlating with increased T cell infiltration. We also treated aged Tsc2+/^– heterozygous (>60 weeks) mice that carry spontaneous Tsc2^–/– tumors with GD3 CAR or untransduced T cells and evaluated them at endpoint. Following CAR T cell treatment, the majority of mice were tumor free while all control animals carried tumors. The outcomes demonstrate a strong treatment effect and suggest that targeting GD3 can be successful in TSC.

Salt-Sensitive Hypertension, Renal Injury, and Renal Vasodysfunction Associated With Dahl Salt-Sensitive Rats Are Abolished in Consomic SS.BN1 Rats

Background

Abnormal renal hemodynamic responses to salt‐loading are thought to contribute to salt‐sensitive (SS) hypertension. However, this is based largely on studies in anesthetized animals, and little data are available in conscious SS and salt‐resistant rats.

Methods and Results

We assessed arterial blood pressure, renal function, and renal blood flow during administration of a 0.4% NaCl and a high‐salt (4.0% NaCl) diet in conscious, chronically instrumented 10‐ to 14‐week‐old Dahl SS and consomic SS rats in which chromosome 1 from the salt‐resistant Brown‐Norway strain was introgressed into the genome of the SS strain (SS.BN1). Three weeks of high salt intake significantly increased blood pressure (20%) and exacerbated renal injury in SS rats. In contrast, the increase in blood pressure (5%) was similarly attenuated in Brown‐Norway and SS.BN1 rats, and both strains were completely protected against renal injury. In SS.BN1 rats, 1 week of high salt intake was associated with a significant decrease in renal vascular resistance (−8%) and increase in renal blood flow (15%). In contrast, renal vascular resistance failed to decrease, and renal blood flow remained unchanged in SS rats during high salt intake. Finally, urinary sodium excretion and glomerular filtration rate were similar between SS and SS.BN1 rats during 0.4% NaCl and high salt intake.

Conclusions

Our data support the concept that renal vasodysfunction contributes to blood pressure salt sensitivity in Dahl SS rats, and that genes on rat chromosome 1 play a major role in modulating renal hemodynamic responses to salt loading and salt‐induced hypertension.

Acute Kidney Injury Associated With Semaglutide

Case reports of acute kidney injury in patients taking the glucagon-like peptide 1 (GLP-1) receptor agonists exenatide and liraglutide have been reported. We report 2 patients with chronic kidney disease due to diabetic kidney disease who experienced rapid worsening of kidney function and increased proteinuria after being prescribed the GLP-1 receptor agonist semaglutide. In 1 patient, kidney biopsy showed advanced diffuse and nodular glomerulosclerosis accompanied by interstitial lymphoplasmacytic and eosinophilic infiltrate and evidence of acute tubular injury. At this time, the long-term outcomes of patients who experience acute kidney injury associated with GLP-1 receptor agonists is not known. We recommend that caution be used with these agents in patients with moderate to severe chronic kidney disease due to limited kidney reserve in the event of an adverse kidney event. Because most adverse kidney events have occurred in patients who experience adverse gastrointestinal symptoms, such patients should have laboratory tests and discontinuation of the medication if there is acute worsening of kidney function.

Human Penile Ossification: A Rare Cause of Sexual Dysfunction - A Case Report and Review of the Literature

Human penile ossification is a rare urologic condition with approximately 40 cases reported in the literature so far. While bone is essential for penetrative intercourse in many non-human mammals, human penile ossification appears to be part of a metaplastic process occurring after injury or trauma. Conditions such as Peyronie’s disease, diabetes mellitus, local trauma, and end-stage renal disease have been associated with this entity. We report the case of a 65-year-old male with penile curvature and a history of painful intercourse who underwent partial excision and grafting with bovine pericardial graft and was found on pathologic examination to have penile ossification.

The Pathology of Amyloidosis in Classification: A Review

BACKGROUND

The amyloidoses are a rare and heterogeneous group of disorders that are characterized by the deposition of abnormally folded proteins in tissues ultimately leading to organ damage. The deposits are mainly extracellular and are recognizable by their affinity for Congo red and their yellow-green birefringence under polarized light. Current classification of amyloid in medical practice is based on the amyloid protein type. To date, 36 proteins have been identified as being amyloidogenic in humans.

SUMMARY

in clinical practice, it is critical to distinguish between treatable versus non-treatable amyloidoses. Moreover, amyloidoses with a genetic component must be distinguished from the sporadic types and systemic amyloidoses must be distinguished from the localized forms. Among the systemic amyloidoses, AL continues to be the most common amyloid diagnosis in the developed world; other clinically significant types include AA, ALECT2, and ATTR. The latter is emerging as an underdiagnosed type in both the hereditary and wild-type setting. Other hereditary amyloidoses include AFib, several amyloidoses derived from apolipoproteins, AGel, ALys, etc. In a dialysis setting, systemic amyloid derived from β2 microglobulin (Aβ2M) should be considered, although a very rare hereditary variant has also been reported; several amyloidoses may be typically associated with aging and several iatrogenic types have also emerged. Determination of the amyloid protein type is imperative before specific therapy can be implemented and the current methods are briefly summarized. A brief overview of the target organ involvement by amyloid type is also included. Key Messages: (1) Early diagnosis of amyloidosis continues to pose a significant challenge and requires the participation of many clinical and laboratory specialties. (2) Determination of the protein type is imperative before specific therapy can be implemented. (3) While mass spectrometry has emerged as the preferred method of amyloid typing, careful application of immune methods is still clinically useful but caution and experience, as well as awareness of the limitations of each method, are necessary in their interpretation. (4) While the spectrum of amyloidoses continues to expand, it is critical to distinguish between those that are currently treatable versus those that are untreatable and avoid causing harm by inappropriate treatment.

Pathophysiology of unilateral ischemia-reperfusion injury: importance of renal counterbalance and implications for the AKI-CKD transition

Unilateral ischemia-reperfusion (UIR) injury leads to progressive renal atrophy and tubulointerstitial fibrosis (TIF) and is commonly used to investigate the pathogenesis of the acute kidney injury-chronic kidney disease transition. Although it is well known that contralateral nephrectomy (CNX), even 2 wk post-UIR injury, can improve recovery, the physiological mechanisms and tubular signaling pathways mediating such improved recovery remain poorly defined. Here, we examined the renal hemodynamic and tubular signaling pathways associated with UIR injury and its reversal by CNX. Male Sprague-Dawley rats underwent left UIR or sham UIR and 2 wk later CNX or sham CNX. Blood pressure, left renal blood flow (RBF), and total glomerular filtration rate were assessed in conscious rats for 3 days before and over 2 wk after CNX or sham CNX. In the presence of a contralateral uninjured kidney, left RBF was lower (P < 0.05) from 2 to 4 wk following UIR (3.6 ± 0.3 mL/min) versus sham UIR (9.6 ± 0.3 mL/min). Without CNX, extensive renal atrophy, TIF, and tubule dedifferentiation, but minimal pimonidazole and hypoxia-inducible factor-1α positivity in tubules, were present at 4 wk post-UIR injury. Conversely, CNX led (P < 0.05) to sustained increases in left RBF (6.2 ± 0.6 mL/min) that preceded the increases in glomerular filtration rate. The CNX-induced improvement in renal function was associated with renal hypertrophy, more redifferentiated tubules, less TIF, and robust pimonidazole and hypoxia-inducible factor-1α staining in UIR injured kidneys. Thus, contrary to expectations, indexes of hypoxia are not observed with the extensive TIF at 4 wk post-UIR injury in the absence of CNX but are rather associated with the improved recovery of renal function and structure following CNX.

Should the Reporting of Bone Marrow Positivity for Amyloid Be Revised? A Critical Assessment Based On 66 Biopsies From a Single Institution

CONTEXT.—

Amyloidoses are rare but heterogeneous disorders for which diagnosis is contingent upon the detection of deposits by Congo red stain and amyloid protein typing determines the treatment options.

OBJECTIVE.—

To address the reporting of bone marrow (BM) involvement by amyloid in relation to the spatial distribution of deposits and to explore whether the location of deposits may have clinical relevance.

DESIGN.—

We examined 66 BM biopsies positive for amyloid with regard to the location and type of amyloid, the percentage and clonality of plasma cells, other organ involvement, and relevant clinical information.

RESULTS.—

In 21 cases, amyloid deposits involved BM stroma, whereas 45 cases were nonstromal. All cases of stromal involvement were typed as AL amyloidosis (or presumed AL), whereas nonstromal involvement was associated with at least 3 types of amyloidosis: AL, ATTR, and AA. The initial diagnosis of amyloidosis was made in a BM specimen in 21 of 66 cases (31.8%). Plasma cells ranged from 1% to 80% (mean, 13.4%; median, 8%; <10% in 44 of 66 specimens [66.6%]) and were monoclonal in 58 of 66 cases (87.8%), and in 54 of 66 cases (81.8%) amyloid deposits were documented in at least one other organ.

CONCLUSIONS.—

This study demonstrates that there is significant heterogeneity in the spatial distribution of amyloid in BM biopsy specimens with medullary, extramedullary, purely vascular, or combined involvement. Whereas stromal deposits were associated exclusively with AL, nonstromal and purely vascular deposits were seen in at least 3 types of systemic amyloidosis (AL, AA, and ATTR). We discuss the reporting of BM biopsy tissue positivity for amyloid deposits.

Penile Paget's Disease: A Case Report and Review of the Literature

Extramammary Paget's Disease (EMPD) is a rare cutaneous, slow growing, intraepithelial adenocarcinoma that can be either primary (intraepithelial arising within the epidermis) or secondary (intraepithelial spread of a visceral carcinoma). Here we present the case of a 63-year-old male with EMPD of the glans penis stemming from underlying urothelial carcinoma. Our treatment decision elected for management with chemotherapy and local treatment with radiation therapy. Subsequent, review of the literature demonstrated a rare disease with a variety of underlying malignancies causing this secondary pathology. Caregivers should be aware of the association of Paget's disease and urothelial cancer and should have a high index of suspicion that erythematous penile lesions may represent Paget's disease and that penile biopsies should be performed early in this setting.

The evaluation of monoclonal gammopathy of renal significance: a consensus report of the International Kidney and Monoclonal Gammopathy Research Group

The term monoclonal gammopathy of renal significance (MGRS) was introduced by the International Kidney and Monoclonal Gammopathy Research Group (IKMG) in 2012. The IKMG met in April 2017 to refine the definition of MGRS and to update the diagnostic criteria for MGRS-related diseases. Accordingly, in this Expert Consensus Document, the IKMG redefines MGRS as a clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin and does not meet previously defined haematological criteria for treatment of a specific malignancy. The diagnosis of MGRS-related disease is established by kidney biopsy and immunofluorescence studies to identify the monotypic immunoglobulin deposits (although these deposits are minimal in patients with either C3 glomerulopathy or thrombotic microangiopathy). Accordingly, the IKMG recommends a kidney biopsy in patients suspected of having MGRS to maximize the chance of correct diagnosis. Serum and urine protein electrophoresis and immunofixation, as well as analyses of serum free light chains, should also be performed to identify the monoclonal immunoglobulin, which helps to establish the diagnosis of MGRS and might also be useful for assessing responses to treatment. Finally, bone marrow aspiration and biopsy should be conducted to identify the lymphoproliferative clone. Flow cytometry can be helpful in identifying small clones. Additional genetic tests and fluorescent in situ hybridization studies are helpful for clonal identification and for generating treatment recommendations. Treatment of MGRS was not addressed at the 2017 IKMG meeting; consequently, this Expert Consensus Document does not include any recommendations for the treatment of patients with MGRS.

This Expert Consensus Document from the International Kidney and Monoclonal Gammopathy Research Group includes an updated definition of monoclonal gammopathy of renal significance (MGRS) and recommendations for the use of kidney biopsy and other modalities for evaluating suspected MGRS

Comparing oncologic outcomes in patients undergoing surgery for oncocytic neoplasms, conventional oncocytoma, and chromophobe renal cell carcinoma

INTRODUCTION

Oncocytic neoplasms are renal tumors similar to oncocytoma, but their morphologic variations preclude definitive diagnosis. This somewhat confusing diagnosis can create treatment and surveillance challenges for the treating urologist. We hypothesize that these subtle morphologic variations do not drastically affect the malignant potential of these tumors, and we sought to demonstrate this by comparing clinical outcomes of oncocytic neoplasms to those of classic oncocytoma and chromophobe.

METHODS

We gathered demographic and outcomes data for patients with variant oncocytic tumors. Oncologic surveillance was conducted per institutional protocol in accordance with NCCN guidelines. Descriptive statistics were used to compare incidence of metastasis and death against those for patients with oncocytoma and chromophobe. Three hundred and fifty-one patients were analyzed: 164 patients with oncocytoma, 28 with oncocytic neoplasms, and 159 with chromophobe tumors.

RESULTS

Median follow-up time for the entire cohort was 32.4 months, (interquartile range 9.2-70.0). Seventeen total patients (17/351, 4.9%) died during the course of the study. In patients with oncocytoma or oncocytic neoplasm, none were known to metastasize or die of their disease. Only chromophobe tumors >6 cm in size in our series demonstrated metastatic progression and approximately half of these metastasized tumors demonstrated sarcomatoid changes.

CONCLUSION

Variant oncocytic neoplasms appear to have a natural course similar to classic oncocytoma. These tumors appear to have no metastatic potential, and oncologic surveillance may not be indicated after surgery.

A Case of Renal Metastasis of Uterine Leiomyosarcoma

A 49-year-old woman with a distant history of uterine leiomyosarcoma underwent robotic-assisted laparoscopic partial nephrectomy for a 3.5 cm right renal mass, which was presumed to be a primary renal cell carcinoma. Surgical margins were negative, and the histologic analysis confirmed leiomyosarcoma. Uterine leiomyosarcoma is traditionally a locally aggressive disease with only rare reports of renal involvement. We report a case of a metastatic leiomyosarcoma to the kidney four years following initial treatment for uterine leiomyosarcoma.

Immunohistochemistry in the workup of prostate biopsies: Frequency, variation and appropriateness of use among pathologists practicing at an academic center

OBJECTIVES

We studied the frequency, inter-pathologist variation, appropriateness and utility of immunohistochemistry (IHC) performed on prostate biopsies (PB) to determine the significance of foci of suspicious glands/atypical small acinar proliferations (ASAP).

METHODS

We calculated the rate of IHC use and diagnostic rate of ASAP and adenocarcinoma in PB from 01/01/2008 to 06/30/2015 for individual pathologists working in a tertiary academic institution, and correlated them with the pathologists' experience, subspecialization and PB volume with the aim of determining the interpathologist variation and appropriateness of use of IHC according to recently published recommendations, and the usefulness of IHC to resolve foci of ASAP as either benign or adenocarcinoma.

RESULTS

IHC was used in 966/2652 (36.4%, 95% CI 33.4-39.4%) PB cases and 1915 of 16,359 (11.7%, 95% CI 11.2%-12.2%) of PB blocks and allowed definitive diagnosis of either benign or malignant in 75.8% (95% CI 73.9-77.7%) of blocks. By pathologist, IHC use rates varied more than twofold (22.8-50.5%); higher use was found for pathologists with genitourinary pathology specialization, higher PB volume and more experience, and correlated with higher rates of both ASAP and adenocarcinoma diagnoses. The use of IHC stains was considered appropriate in 822/966 (85.1%, 95% CI 82.9-87.4%) cases.

CONCLUSIONS

Despite the fact that the use of IHC stains was considered useful and deemed appropriate in the majority of cases, it showed wide variation between pathologists, suggesting monitoring of IHC use rates may be useful to standardize its use.

Relative antihypertensive and glomeruloprotective efficacies of enalapril and candesartan cilexetil in the remnant kidney model

The present studies were performed to investigate whether the differences described between the two modalities for interruption of the renin-angiotensin-aldosterone system (RAAS), angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin AT 1receptor antagonists (AIIA) result in differences in renoprotective efficacy in the rat remnant kidney model. Male Sprague-Dawley rats with an initial body weight of 225—300 g, underwent 5/6 renal ablation and had radiotransmitters installed for radiotelemetric blood pressure (BP) measurements, owing to the known limitations of periodic tail-cuff BP measurements to adequately reflect ambient BP profiles. After renal ablation surgery, the rats received no treatment (n=10); enalapril (n=11) or candesartan (n=9) after the first week, both administered initially at a dose of 50 mg/l of drinking water (~10 mg/kg). However, the dose of candesartan had to be reduced to 10—25 mg/l in 4/9 rats to avoid excessive hypotension. Both enalapril and candesartan produced significant reductions in average systolic BP during the subsequent approximately six weeks of observations as compared with untreated rats (187±4 mmHg, p<0.001), but candesartan was significantly more effective at these relative doses (121±3 vs. 133±4 mmHg, p<0.05). At approximately seven weeks, serum creatinine and proteinuria were measured before sacrifice for morphologic assessment of percentage glomerulosclerosis (GS). Despite the described differences between ACE-I and AIIA after acute administration, the percentage GS was reduced similarly by enalapril (down to 6.8±2.8%) and candesartan (down to 2.9±1.5%) as compared with untreated rats (37.2±4.3%). Moreover, GS in individual animals paralleled the BP reductions achieved. Proteinuria was reduced in parallel to the decrease in % GS. These data indicate that, at least in the 5/6 renal ablation model, RAAS blockade by either ACE-I or AIIA provides protection by BPdependent rather than BP-independent mechanisms. This may reflect the primarily hypertensive pathogenesis of GS in this model, and the fact that hypertension is also very angiotensin II-dependent in this model. Thus, these data suggest that models other than the 5/6 ablation model may be more appropriate to demonstrate the BP-independent protective effects of RAAS blockade.

Oligometastatic Growing Teratoma Syndrome: A Case for an Aggressive Surgical Approach

Growing teratoma syndrome is an infrequent presentation of testicular cancer. We present a case of growing teratoma syndrome in a patient who initially presented with clinical stage I nonseminomatous testicular germ cell tumor, who subsequently developed large volume oligometastases to the retroperitoneum, thorax, and thigh. Despite two regimens of chemotherapy, his disease progressed. Complete surgical extirpation of all gross tumors confirmed mature teratoma. An aggressive surgical approach, including postchemotherapy resection of all known metastatic sites, can provide long-term disease-free survival.

Tubulocystic Carcinoma of the Kidney With Poorly Differentiated Foci: A Frequent Morphologic Pattern of Fumarate Hydratase-deficient Renal Cell Carcinoma

An emerging group of high-grade renal cell carcinomas (RCCs), particularly carcinomas arising in the hereditary leiomyomatosis renal cell carcinoma syndrome (HLRCC), show fumarate hydratase (FH) gene mutation and loss of function. On the basis of similar cytomorphology and clinicopathologic features between these tumors and cases described as tubulocystic carcinomas with poorly differentiated foci (TC-PD) of infiltrative adenocarcinoma, we hypothesized a relationship between these entities. First, 29 RCCs with morphology of TC-PD were identified retrospectively and assessed for FH expression and aberrant succination (2SC) by immunohistochemistry (IHC), with targeted next-generation sequencing of 409 genes-including FH-performed on a subset. The 29 TC-PD RCCs included 21 males and 8 females, aged 16 to 86 years (median, 46), with tumors measuring 3 to 21 cm (median, 9) arising in the right (n=16) and left (n=13) kidneys. Family history or stigmata of HLRCC were identifiable only retrospectively in 3 (12%). These tumors were aggressive, with 79% showing perinephric extension, nodal involvement in 41%, and metastasis in 86%. Of these, 16 (55%) demonstrated loss of FH by IHC (14/14 with positive 2SC). In contrast, 5 (17%) showed a wild-type immunoprofile of FH+/2SC-. An intriguing group of 8 (28%) showed variable FH± positivity, but with strong/diffuse 2SC+. Next-generation sequencing revealed 8 cases with FH mutations, including 5 FH-/2SC+ and 3 FH±/2SC+ cases, but none in FH+/2SC- cases. Secondly, we retrospectively reviewed the morphology of 2 well-characterized cohorts of RCCs with FH-deficiency determined by IHC or sequencing (n=23 and n=9), unselected for TC-PD pattern, identifying the TC-PD morphology in 10 (31%). We conclude that RCCs with TC-PD morphology are enriched for FH deficiency, and we recommend additional workup, including referral to genetic counseling, for prospective cases. In addition, based on these and other observations, we propose the term "FH-deficient RCC" as a provisional term for tumors with a combination of suggestive morphology and immunophenotype but where genetic confirmation is unavailable upon diagnosis. This term will serve as a provisional nomenclature that will enable triage of individual cases for genetic counseling and testing, while designating these cases for prospective studies of their relationship to HLRCC.

Standardized Reporting of Microscopic Renal Tumor Margins: Introduction of the Renal Tumor Capsule Invasion Scoring System

PURPOSE

Renal tumor enucleation allows for maximal parenchymal preservation. Identifying pseudocapsule integrity is critically important in nephron sparing surgery by enucleation. Tumor invasion into and through the capsule may have clinical implications, although it is not routinely commented on in standard pathological reporting. We describe a system to standardize the varying degrees of pseudocapsule invasion and identify predictors of invasion.

MATERIALS AND METHODS

We performed a multicenter retrospective review between 2002 and 2014 at Indiana University Hospital and Loyola University Medical Center. A total of 327 tumors were evaluated following removal via radical nephrectomy, standard margin partial nephrectomy or enucleation partial nephrectomy. Pathologists scored tumors using our i-Cap (invasion of pseudocapsule) scoring system. Multivariate analysis was done to determine predictors of higher score tumors.

RESULTS

Tumor characteristics were similar among surgical resection groups. Enucleated tumors tended to have thinner pseudocapsule rims but not higher i-Cap scores. Rates of complete capsular invasion, scored as i-Cap 3, were similar among the surgical techniques, comprising 22% of the overall cohort. Papillary histology along with increasing tumor grade was predictive of an i-Cap 3 score.

CONCLUSIONS

A capsule invasion scoring system is useful to classify renal cell carcinoma pseudocapsule integrity. i-Cap scores appear to be independent of surgical technique. Complete capsular invasion is most common in papillary and high grade tumors. Further work is warranted regarding the relevance of capsular invasion depth as it relates to the oncologic outcome for local recurrence and disease specific survival.

Adenovirus disease in six small bowel, kidney and heart transplant recipients; pathology and clinical outcome

Adenoviruses are emerging as important viral pathogens in hematopoietic stem cell and solid organ transplant recipients, impacting morbidity, graft survival, and even mortality. The risk seems to be highest in allogeneic hematopoietic stem cell transplant recipients as well as heart, lung, and small bowel transplant recipients. Most of the adenovirus diseases develop in the first 6 months after transplantation, particularly in pediatric patients. Among abdominal organ recipients, small bowel grafts are most frequently affected, presumably due to the presence of a virus reservoir in the mucosa-associated lymphoid tissue. Management of these infections may be difficult and includes the reduction of immunosuppression, whenever possible, combined with antiviral therapy, if necessary. Therefore, an awareness of the pathology associated with such infections is important in order to allow early detection and specific treatment. We reviewed six transplant recipients (small bowel, kidney, and heart) with adenovirus graft involvement from two institutions. We sought to compare the diagnostic morphology and the clinical and laboratory findings. The histopathologic features of an adenovirus infection of the renal graft and one native kidney in a heart transplant recipient included a vaguely granulomatous mixed inflammatory infiltrate associated with rare cells showing a cytopathic effect (smudgy nuclei). A lymphocytic infiltrate, simulating T cell rejection, with admixture of eosinophils was also seen. In the small bowel grafts, there was a focal mixed inflammatory infiltrate with associated necrosis in addition to cytopathic effects. In the heart, allograft adenovirus infection was silent with no evidence of inflammatory changes. Immunohistochemical stain for adenovirus was positive in all grafts and in one native kidney. All patients were subsequently cleared of adenovirus infection, as evidenced by follow-up biopsies, with no loss of the grafts. Adenovirus infection can involve allografts as well as native organs in solid organ transplant recipients. Infection is associated with variable necrosis and acute inflammation, in addition to a rejection-like infiltrate. Hematuria in non-renal solid organ transplant recipients may be associated with adenovirus nephritis and clinically silent graft involvement. Prompt diagnosis (aided by immunohistochemistry (IHC) and serology), with specific treatment, can prevent graft loss.

Proteomics and mass spectrometry in the diagnosis of renal amyloidosis

The amyloidoses are a ‘group’ of disorders, all of which are associated with deposits that display similar staining and ultrastructural features and are toxic to tissues. Many proteins—currently 31 protein types and many more variants—have been shown to undergo such transformations. Among the various currently known amyloidoses, there are marked differences with regard to their pathogenesis and incidence, while the associated clinical picture is frequently overlapping. However, the therapies that are currently available are amyloid-type specific. The diagnosis of amyloidosis thus involves two steps: (i) a generic diagnosis, followed by (ii) an amyloid type-specific diagnosis or ‘amyloid typing’. Immunofluorescence in frozen sections or immunohistochemistry (IHC) in paraffin sections has traditionally been used in the typing of amyloid. However, IHC of amyloid differs significantly from IHC in other areas of surgical pathology; both caution and experience are necessary for its interpretation. The rationale for the application of proteomic methods to amyloid typing lies in the relative abundance of amyloid proteins in tissue where, frequently, it is the ‘dominant’ protein. Proteomic techniques include the following steps: sample preparation, protein extraction and digestion into peptide fragments, followed by their subsequent separation and measurement by mass spectrometry (MS) and protein identification by informatics. The advantages as well as the limitations of both methods—immunohistochemistry and MS-based proteomics—are discussed. The current recommendations for the application of proteomics in renal amyloidosis are summarized.

Hemodynamic basis for the limited renal injury in rats with angiotensin II-induced hypertension

ANG II is thought to increase the susceptibility to hypertension-induced renal disease (HIRD) via blood pressure (BP)-dependent and BP-independent pathways; however, the quantitative relationships between BP and HIRD have not been examined in ANG II-infused hypertensive rats. We compared the relationship between radiotelemetrically measured BP and HIRD in Sprague-Dawley rats (Harlan) chronically administered ANG II (300-500 ng·kg(-1)·min(-1), n = 19) for 4 wk versus another commonly employed pharmacological model of hypertension induced by the chronic administration of N(ω)-nitro-l-arginine methyl ester (l-NAME, 50 mg·kg(-1)·day(-1), n = 23). [DOSAGE ERROR CORRECTED]. Despite the significantly higher average systolic BP associated with ANG II (191.1 ± 3.2 mmHg) versus l-NAME (179.9 ± 2.5 mmHg) administration, the level of HIRD was very modest in the ANG II versus l-NAME model as evidenced by significantly less glomerular injury (6.6 ± 1.3% vs. 11.3 ± 1.5%, respectively), tubulointerstitial injury (0.3 ± 0.1 vs. 0.7 ± 0.1 injury score, respectively), proteinuria (66.3 ± 10.0 vs. 117.5 ± 10.1 mg/day, respectively), and serum creatinine levels (0.5 ± 0.04 vs. 0.9 ± 0.07 mg/dl, respectively). Given that HIRD severity is expected to be a function of renal microvascular BP transmission, BP-renal blood flow (RBF) relationships were examined in additional conscious rats administered ANG II (n = 7) or l-NAME (n = 8). Greater renal vasoconstriction was observed during ANG II versus l-NAME administration (41% vs. 23% decrease in RBF from baseline). Moreover, administration of ANG II, but not l-NAME, led to a unique BP-RBF pattern in which the most substantial decreases in RBF were observed during spontaneous increases in BP. We conclude that the hemodynamic effects of ANG II may mediate the strikingly low susceptibility to HIRD in the ANG II-infused model of hypertension in rats.

Expanding the Morphologic Spectrum of Adult Biphasic Renal Tumors—Mixed Epithelial and Stromal Tumor of the Kidney With Focal Papillary Renal Cell Carcinoma

Mixed epithelial and stromal tumor (MEST) is a distinctive adult biphasic neoplasm of the kidney characterized by the presence of solid and cystic areas composed of spindled stroma and epithelium lining tubules and cystic spaces respectively. Most MESTs are benign although sarcomatous transformation has rarely been reported. It has not been clearly established whether the epithelial component represents entrapped tubules or constitutes a true neoplastic component. We report an unusual case of a biphasic tumor of the kidney with a benign stroma and a focal component of papillary carcinoma arising in one of the cysts and discuss its pathogenesis.

Positioning ganglioside D3 as an immunotherapeutic target in lymphangioleiomyomatosis

Tumors that develop in lymphangioleiomyomatosis (LAM) as a consequence of biallelic loss of TSC1 or TSC2 gene function express melanoma differentiation antigens. However, the percentage of LAM cells expressing these melanosomal antigens is limited. Here, we report the overexpression of ganglioside D3 (GD3) in LAM. GD3 is a tumor-associated antigen otherwise found in melanoma and neuroendocrine tumors; normal expression is largely restricted to neuronal cells in the brain. We also observed markedly reduced serum antibody titers to GD3, which may allow for a population of GD3-expressing LAM cells to expand within patients. This is supported by the demonstrated sensitivity of cultured LAM cells to complement mediated cytotoxicity via GD3 antibodies. GD3 can serve as a natural killer T (NKT) cell antigen when presented on CD1d molecules expressed on professional antigen-presenting cells. Although CD1d-expressing monocyte derivatives were present in situ, enhanced NKT-cell recruitment to LAM lung was not observed. Cultured LAM cells retained surface expression of GD3 over several passages and also expressed CD1d, implying that infiltrating NKT cells can be directly cytotoxic toward LAM lung lesions. Immunization with antibodies to GD3 may thus be therapeutic in LAM, and enhancement of existing NKT-cell infiltration may be effective to further improve antitumor responses. Overall, we hereby establish GD3 as a suitable target for immunotherapy of LAM.

Renal Lymph Nodes for Tumor Staging: Appraisal of 871 Nephrectomies With Examination of Hilar Fat

Context.—Despite decades of research, the role of lymphadenectomy in the management of renal cell carcinoma (RCC) is still not clearly defined. Before the implementation of targeted therapies, lymph node metastases were considered to be a portent of markedly decreased survival, regardless of the tumor stage. However, the role of lymphadenectomy and the relative benefit of retroperitoneal lymph node dissection in the context of modern adjunctive therapies have not been conclusively addressed in the clinical literature. The current pathologic literature does not offer clear recommendations with regard to the minimum number of lymph nodes that should be examined in order to accurately stage the pN in renal cell carcinoma. Although gross examination of the hilar fat to assess the nodal status is performed routinely, it has not yet been determined whether this approach is adequate.

Objective.—To evaluate the status of lymph nodes and their rate of identification in the pathologic examination of nephrectomy specimens in adult renal malignancies.

Design.—We reviewed the operative and pathology reports of 871 patients with renal malignancies treated by nephrectomy. All tumors were classified according to the seventh edition of the Tumor-Nodes-Metastasis classification. Patients were divided into 3 groups: Nx, no lymph nodes recovered; N0, negative; and N1, with positive lymph nodes. Grossly visible lymph nodes were submitted separately; as per grossing protocol, hilar fatty tissue was submitted for microscopic examination. We evaluated the factors that affected the number of lymph nodes identified and the variables that allowed the prediction of nodal involvement.

Results.—Lymph nodes were recovered in 333 of 871 patients (38%): hilar in 125 patients, nonhilar in 137 patients, and hilar and nonhilar in 71 patients. Patients with positive lymph nodes (n = 87) were younger, had larger primary tumors, and had lymph nodes of average size, as well as a higher pT stage, nuclear grade, and rate of metastases. Metastases were seen only in grossly identified lymph nodes (65% hilar, 16% nonhilar); all microscopic nodes were negative. Even with the microscopic examination of fat, hilar lymph nodes were recovered in only 22.5% of patients. A nonhilar route of node metastasis was suspected in 40 patients.

Conclusions.—Only grossly identifiable lymph nodes, both hilar and nonhilar, were positive for metastases. Although microscopic examination of the hilar fat increased the number of lymph nodes recovered, the identification rate of these nodes was low (22.5%), and such microscopic nodes were invariably negative. Hence, microscopic examination of the hilar fat may be unnecessary.