Histologic Diagnosis of Renal Mass Biopsy

Clear-cell papillary renal cell tumour: New insights into clinicopathological features and molecular landscape after renaming by 5th WHO classification

OBJECTIVE

Clear cell papillary renal cell tumour (CCPRCT) is a kind of renal epithelial cell tumor, and was renamed by the 5th WHO due to its specific epidemiology and clinicopathological characteristics. However, the biological mechanism and molecular basis of CCPRCT still need to be further clarified. This study aims to comprehensively evaluate clinicopathologic and molecular characteristics of CCPRCC, and particularly compare it with other more prevalent subtypes of renal cell carcinoma.

METHODS

12 cases of CCPRCT were collected for analyzing the clinicopathological characteristics. Then, whole-exome sequencing (WES) was employed to reveal the genetic profiles, followed by comparison with the molecular genetic alterations identified in ccRCC (341) and pRCC (200) datasets obtained from the TCGA database.

RESULTS

Of the 12 CCPRCT cases, the male-to-female ratio was 4:1 with a mean age of 49.5 years (48.5 ± 10.5) at diagnosis. All patients were diagnosed accidentally during routine physical examinations. All tumors (12/12, 100%）had a solid-cystic appearance with a well-defined fibrous capsule. The median size of the tumors was 3 cm (2.98 ± 1.2). Histologically, the cystic papillary structures were considered to be prominent, lined with cuboidal tumor cells away from basement membrane. The tumor cells were moderately atypia equivalent to grade 1 or grade 2 according to the ISUP nuclear grading system. Typically, the tumor cell diffusely positive for CK7 and CAIX in a "cup-like" pattern. The results of WES revealed recurrent gene alterations (mainly missense mutation) of TTN and FLT in 4 cases (4/12, 33.3%), respectively, of which, the alteration of FLT was not observed in ccRCC and pRCC of the TCGA database. Other gene alterations including POTEC (1 cases), PRADC1 (1 cases), ZZZ3 (1 case) and PTPRZ1 (1 case), etc. Moreover, all of the CCPRCT cases displayed a lower tumor mutation burden (TMB) compared to ccRCC and pRCC with median TMB of 1.04 (range: 1.94 ± 2.74). None of the patients experienced tumor metastasis, recurrence, or tumor-related deaths.

CONCLUSION

CCPRCT is a renal epithelial cell tumor characterized by specific clinical and pathological features. Our study provides additional evidence supporting the favorable prognosis of CCPRCT. Furthermore, the potential molecular alterations were uncovered by this study in CCPRCT such as the FLT family and TTN. However, due to the limited sample size, larger studies are required to validate these findings.

Application of contrast-enhanced ultrasound in renal space-occupying lesion puncture biopsy

OBJECTIVE

The purpose of this study was to investigate the utility of contrast-enhanced ultrasound (CEUS) in percutaneous renal space-occupying lesion puncture biopsy.

METHODS

Ultrasound (US)-guided percutaneous needle biopsies were performed on 55 patients with renal space-occupying lesions, and the results were analyzed retrospectively. The US group included 36 patients receiving conventional US, and the contrast-enhanced ultrasound (CEUS) group included 22 patients, including 19 patients receiving CEUS directly and 3 patients receiving additional enhanced ultrasound due to the first conventional ultrasound puncture failure. The relevant data were subjected to statistical analysis.

RESULTS

The results of this study showed that the successful rate of obtaining effective tissue (100% vs. 75%) and the puncture accuracy (100% vs. 88.89%) in CEUS group were significantly higher than those in US group (P < 0.05). CEUS-guided puncture biopsy of renal mass, especially in the case of urothelial carcinoma of the renal pelvis, outperforms conventional ultrasound, and the difference was statistically significant (P < 0.05).

CONCLUSION

Percutaneous renal space-occupying lesion puncture biopsies aided by CEUS yield more effective tissue and improved puncture accuracy.

The effect of refined nursing education on improving the urination of patients after renal biopsy

BACKGROUND

To investigate the clinical effect of better nursing education on patients' postoperative urination after renal biopsy.

METHODS

In this study, patients who underwent renal biopsy in the Department of Nephrology at our hospital were selected as the observation group (July-December 2018, n = 120) and control group (January-June 2018, n = 110) and received refined nursing education and routine nursing education, respectively. Postoperatively, the causes of dysuria after puncture, the degree of postoperative pain, and the urination mode were compared between the two groups.

RESULTS

Six patients in the observation group and 23 patients in the control group needed urethral catheterization, accounting for about 5% and 15.2%, respectively. Therefore, the postoperative catheterization rate in the observation group was significantly lower than the control group, with a statistically significant difference.

CONCLUSION

The refined nursing education proposed in this study can effectively improve urinary dysfunction after renal biopsy and has a clinical promotional value.

Shear Wave Elastography for Assessment of Biopsy-Proven Renal Fibrosis: A Systematic Review and Meta-analysis

The purpose of this meta-analysis was to evaluate the diagnostic performance of shear wave elastography (SWE) for the staging of renal fibrosis in patients with chronic kidney disease (CKD). Classification of CKD into mild, moderate and severe fibrosis was based on renal biopsy pathology (glomerulosclerosis, tubulointerstitial injury and vascular sclerosis). The Cochrane Library, Medline, PubMed, Web of Science, EMBASE and CNKI databases were searched from January 1, 2009, to April 20, 2022. Pooled sensitivity, specificity, diagnostic odds ratio and area under the receiver operating characteristic curve (AUROC) were calculated using random effects models. A total of 1394 patients from 14 studies were included in the final analysis. For mild, moderate and severe renal fibrosis, SWE had a sensitivity of 0.79 (95% confidence interval [CI]: 0.67-0.88), 0.73 (95% CI: 0.65-0.80) and 0.87 (95% CI: 0.71-0.95); a specificity of 0.82 (95% CI: 0.75-0.87), 72% (95% CI: 0.67-0.77) and 0.83 (95% CI: 0.80-0.86); an AUROC of 0.87 (95% CI: 0.84-0.90), 0.78 (95% CI: 0.75-0.82) and 0.86 (95% CI: 0.82-0.88); and a diagnostic odds ratio of 17 (95% CI: 7-43), 7 (95% CI: 4-12) and 34 (95% CI: 13-88), respectively. Meta-regressions revealed that the publication date, system used and number of valid measurements of SWE were the main causes of heterogeneity. SWE is a good technique for diagnosing mild and severe renal fibrosis, as well as a fair technique for diagnosing moderate fibrosis.

Evolution in the Pathologic Classification of Renal Neoplasia

The pathologic classification of renal tumors is a dynamic and complex process, which has evolved to a "histomolecular" driven system. Despite advances in molecular characterization, most renal tumors can be diagnosed by morphology with or without using a limited set of immunohistochemical stains. If access to molecular resources and specific immunohistochemical markers is limited, pathologists may face difficulties in following an optimal algorithm to classify renal tumors. In this article, we detail the historical evolution of renal tumor classification, including a synopsis of major changes introduced by the current fifth edition World Health Organization 2022 classification of renal epithelial tumors.

Ultrasound-Guided Lauromacrogol Injection for the Treatment of Active Bleeding After Renal Biopsy

Background: This study aimed to describe the technique and outcomes of hemostasis for ultrasound-guided lauromacrogol injection for active bleeding after renal biopsy. Methods: Data from patients with active bleeding after renal biopsy between January 2018 and December 2020 were retrospectively collected. Patients who still had active bleeding after 30 min of compression were then injected with lauromacrogol under ultrasound guidance. The patient's symptoms before and after operation were collected to assess whether they had severe complications. Changes in hemoglobin and serum creatinine values were collected. Results: Data from a total of 15 patients with active bleeding after renal biopsy were collected, including data of 6 men and 9 women. After the operation, there were 11 cases of mild back pain; 1 case of chills, cold sweats, and back pain; 1 case of cold sweats and blood pressure reduction, and 2 cases with no obvious symptoms. No severe complications occurred in this study, and active bleeding was stopped in all patients. After the operation, compared with before the operation, there was no statistically significant difference in the hemoglobin value and serum creatinine value (p = 0.10 > 0.05, p = 0.78 > 0.05). Conclusion: Ultrasound-guided lauromacrogol injection is a relatively simple, safe and feasible method, which could be helpful in treating active bleeding in the immediate post-procedure period after renal biopsy.

Immunohistochemistry for the diagnosis of renal epithelial neoplasms

Despite the increasing number of newly identified renal neoplasms, the diagnosis of renal cell carcinoma (RCC) can usually be reached with careful histologic examination and a limited immunohistochemical (IHC) panel. Clear cell, papillary, chromophobe RCC and oncocytoma account for more than 90% of renal neoplasia in adults, and sophisticated ancillary tools are usually unnecessary. Renal tumors with entity-defining genetic alterations may ultimately require molecular confirmation via cytogenetics or sequencing technologies, such as RCC with TFE3, TFEB, or ALK gene rearrangements, or TFEB amplified RCC. In fumarate hydratase-deficient and succinate dehydrogenase-deficient RCC, highly specific IHC markers can strongly suggest the diagnosis. In the metastatic setting, PAX8 and carbonic anhydrase 9 are among the most helpful markers for confirming RCC and clear cell type, respectively; however, caution should be exercised in the absence of a current or historical renal mass. In diagnostically challenging cases, such as renal eosinophilic tumors with low-grade nuclear features, or infiltrative high-grade tumors, careful examination coupled with a judicious panel of IHC markers usually resolves the diagnosis. This review offers concise algorithms for diagnosis of kidney neoplasia with the latest recognized, provisional, and emerging entities to daily pathology practice.

Application of B-ultrasound information image in Renal Puncture Biopsy treatment and Nursing

Objectives

This study was to explore the application value of B-ultrasound in guiding puncture biopsy of chronic kidney disease (CKD) and the clinical nursing effects under the guidance of B-ultrasound.

Methods

Pathological examination of kidney biopsy was performed on 94 patients with CKD under the guidance of ultrasound from August 2020 to December 2020.; patients were observed for symptoms such as low back pain, backache, hematuria, and subcapsular hematoma. Color Doppler ultrasonography was performed on the punctured patients on day 1, 2, and 3 to observe whether there was subrental hematoma. The pathological results were analyzed and the success rate of percutaneous renal biopsy under ultrasound guidance was analyzed. Before the patient was discharged, investigate the satisfaction with the nursing work.

Results

(1) After the puncture, 45 patients developed low back pain and low back pain symptoms, 12 cases developed subcapsular hematoma; 8 cases showed gross hematuria, 62 cases showed microscopic hematuria, and the rest had no obvious symptoms; (2) the nursing satisfaction rate of 94 cases was as high as 95.7%.

Conclusion

US-PRB is a safe and effective auxiliary examination method, which can improve the success rate of puncture and reduce postoperative complications. Effective nursing can reduce the incidence of postoperative complications and improve patient satisfaction.

Diagnostic accuracy of core biopsies of renal masses: Experience in a real-life setting from a tertiary center

OBJECTIVE

To document and analyze diagnostic accuracy of renal core biopsy (RCB), its diagnostic correlation with resection specimens, and to question the need for immunohistochemistry (IHC) in the preoperative diagnosis of renal masses.

MATERIAL AND METHOD

RCBs performed at a reference center between 2007 and 2017 were included. Pathological, clinical, and radiological data were obtained from medical records.

RESULTS

Among 302 biopsies included in this study, 274 (90.7%) were diagnostic. Two hundred sixty-six were neoplastic and 179 were of primary renal origin. The most common secondary neoplasms were hematolymphoid (n = 35) and metastatic (n = 17). Sixty-nine tumors were classified as small renal masses (SRMs) (≤4 cm in diameter) and 53 of them were malignant. Nephrectomy was performed in 58 patients. Overall diagnostic accuracy between resections and RCBs was 88.7%. IHC was performed in 160 (53%) cases. In 15 of those, a definite diagnosis could not be rendered. Renal cell origin and subtype were determined by histomorphology alone in 81 and 75 cases, respectively. Sixty primary neoplasms of renal cell origin required IHC for diagnosis.

CONCLUSION

RCB is a safe and highly accurate method for the diagnosis of both primary and secondary renal neoplasms. IHC is mostly required for the diagnosis of secondary tumors. Histomorphology is still the primary diagnostic tool, highly dependent on the experience of the surgical pathologist.

Inflammatory pseudotumor of Castleman disease and IgG4-related disease masquerading as kidney malignancy

Background

With widespread clinical application of imaging techniques, renal space-occupying lesions have been identified at an increasing frequency. Here, we report two rare cases, Castleman disease (CD) and IgG4-related disease (IgG4-RD), presenting primarily with the symptoms and imaging findings of kidney malignancy.

Case presentation

In case 1, an occupying lesion located in the right renal pelvis was detected using magnetic resonance imaging in a 32-year-old female who presented with hematuria and lumbago. First misdiagnosed as carcinoma of the renal pelvis, the patient underwent right radical nephroureterectomy. However, postoperative pathological and immunohistochemistry studies finally confirmed the diagnosis of CD. In case 2, a 45-year-old male presented with the chief complaint of anuria. Nephrostomy and renal biopsy indicated lymphoma, following which, antegrade urography and computed tomography urography were performed, which revealed bilateral hydronephrosis and mass lesions around the renal pelvis. Partial resection of the masses and frozen section examination indicated the diagnosis of CD. However, the results of postoperative histopathology and immunohistochemistry combined with serum IgG4 were consistent with IgG4-RD. Both the patients recovered well after drug treatment without recurrence of the diseases.

Conclusions

Inflammatory pseudotumor of CD and IgG4-RD with kidney involvement are primarily diagnosed by postoperative histopathology and can pose a preoperative diagnostic challenge because these lesions can masquerade as kidney malignancy. Therefore, we recommend core biopsy as a nonnegligible procedure to evaluate renal masses and potentially prevent unnecessary surgical treatment.

The Clinicopathologic and Molecular Landscape of Clear Cell Papillary Renal Cell Carcinoma: Implications in Diagnosis and Management

BACKGROUND

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently described tumor entity. Several questions remain about its epidemiology, molecular features, and clinical behavior.

OBJECTIVE

To comprehensively evaluate clinicopathologic and molecular features of CCPRCC, and compare it with more common kidney cancer subtypes.

DESIGN, SETTING, AND PARTICIPANTS

We identified 89 CCPRCC patients and compared their clinicopathologic features with 1120 localized clear cell renal cell carcinoma (ccRCC) and 129 type 1 papillary renal cell carcinoma (pRCC) patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Nonparametric statistical testing was used to compare relevant features between tumor types. Overall, cancer-specific survival (CSS) and metastasis-free survival estimates were calculated from initial diagnosis using the Kaplan-Meier method. Patients with ipsilateral multifocal disease were explored further. A subset of CCPRCC tumors underwent genomic analysis and were compared with other RCC subtypes.

RESULTS AND LIMITATIONS

A higher proportion of female (45% vs 32%) and African-American (19% vs 3%) patients were observed in the CCPRCC cohort than in the ccRCC and pRCC cohorts. CCPRCC tumors also had increased odds of presenting with additional ipsilateral masses (odds ratio [OR]: 4.41 [confidence interval {CI}: 2.34, 8.15], p < 0.001) and bilateral disease (OR: 4.80 [CI: 2.40, 9.59], p < 0.001) compared with ccRCC tumors. On molecular analysis, CCPRCC tumors showed fewer somatic aberrations and a greater degree of mitochondrial DNA depletion. In multifocal CCPRCC tumors, histologic concordance among the different renal cell carcinoma masses was estimated at 44% (7/16), and none of the individuals presenting exclusively with CCPRCC tumors developed metastatic disease after 5 yr. In contrast, multifocal tumors with CCPRCC and other nonconcordant histologies were more likely to experience adverse outcomes (CSS, log rank p = 0.034).

CONCLUSIONS

CCPRCC is characterized by distinct molecular and epidemiologic features that could be used to refine current diagnostic approaches. Although their clinical course is generally indolent, multifocal CCPRCC tumors represent a unique diagnostic challenge. In this context, single-mass biopsies could miss concomitant aggressive disease, with a potential negative impact on patient outcomes. Furthermore, high discordance rates in multifocal CCPRCC tumors have important clinical implications in management.

PATIENT SUMMARY

We explored the molecular and clinical features of clear cell papillary renal cell carcinoma (CCPRCC) relative to other kidney cancer subtypes. While CCPRCC generally conveys a good prognosis, additional caution should be taken when it is diagnosed using biopsy if multiple kidney masses are present.

Renal Cell Carcinoma Diagnosis After Initial Detection on Screening Mammogram

Renal cell carcinoma (RCC) defines a varied class of primary renal neoplasms which arise from the renal cortex. Because RCC often progresses silently to a very advanced metastatic stage, the majority of RCC cases are diagnosed either incidentally on abdominal imaging or upon presentation of invasive disease at metastatic sites. This case profiles a 57-year-old woman with distant history of resected RCC who presented with a posterior breast mass that was diagnosed as metastatic recurrence of RCC through mammogram, ultrasound, and core biopsy. Although the breast is an unusual site for metastasis, clinicians should consider metastatic RCC as a possible etiology when evaluating women with history of RCC and a newly discovered breast mass.