[Vancouver classification of renal tumors: Recommendations of the 2012 consensus conference of the International Society of Urological Pathology (ISUP)]

Clinicopathological characteristics and typing of multilocular cystic renal neoplasm of low malignant potential

BACKGROUND

Up until now, no research has been reported on the association between the clinical growth rate of multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) and computed tomography (CT) imaging characteristics. Our study sought to examine the correlation between them, with the objective of distinguishing unique features of MCRNLMP from renal cysts and exploring effective management strategies.

AIM

To investigate optimal management strategies of MCRNLMP.

METHODS

We retrospectively collected and analyzed data from 1520 patients, comprising 1444 with renal cysts and 76 with MCRNLMP, who underwent renal cyst decompression, radical nephrectomy, or nephron-sparing surgery for renal cystic disease between January 2013 and December 2021 at our institution. Detection of MCRNLMP utilized the Bosniak classification for imaging and the 2016 World Health Organization criteria for clinical pathology.

RESULTS

Our meticulous exploration has revealed compelling findings on the occurrence of MCRNLMP. Precisely, it comprises 1.48% of all cases involving simple renal cysts, 5.26% of those with complex renal cysts, and a noteworthy 12.11% of renal tumors coexisting with renal cysts, indicating a statistically significant difference (P = 0.001). Moreover, MCRNLMP constituted a significant 22.37% of the patient population whose cysts demonstrated a rapid growth rate of ≥ 2.0 cm/year, whereas it only represented 0.66% among those with a growth rate below 2.0 cm/year. Of the 76 MCRNLMP cases studied, none of the nine patients who underwent subsequent nephron-sparing surgery or radical nephrectomy following renal cyst decompression experienced recurrence or metastasis. In the remaining 67 patients, who were actively monitored over a 3-year postoperative period, only one showed suspicious recurrence on CT scans.

CONCLUSION

MCRNLMP can be tentatively identified and categorized into three types based on CT scanning and growth rate indicators. In treating MCRNLMP, partial nephrectomy is preferred, while radical nephrectomy should be minimized. After surgery, active monitoring is advisable to prevent unnecessary nephrectomy.

Multilocular Cystic Renal Neoplasm of Low Malignant Potential: A Case Report and Literature Review

Multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) is a rare subtype of renal cell carcinoma that has a favorable outcome. Most cases of MCRNLMP usually present as distinct multilocular cystic lesions; however, they may appear as small complicated cysts with hemorrhagic components. Herein, we present a case of MCRNLMP and provide a review of the literature.

Pathology and systemic therapy of non-clear cell renal cell carcinoma: an overview

Introduction: Non-clear cell renal cell carcinoma (nccRCC) represents a highly heterogenous group of kidney cancer entities. As most clinical trials predominantly include patients with clear cell RCC (ccRCC), nccRCC treatment guidelines are mainly extrapolated from recommendations in ccRCC. Here, we review and elucidate current data on the pathologic classification and treatment of nccRCC.Areas covered: This article gives an overview of the WHO classification of RCC, showing the histological diversity of nccRCC and focusing particularly on entities first characterized since 2016, their specific molecular behavior and their role as indicators for hereditary cancer syndromes. In this context, we discuss the available data on nccRCC treatment oprtions such as tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, cytotoxic chemotherapy, and immune checkpoint inhibitors.Expert opinion: Although nccRCCs are relatively uncommon, entities of this type account for a subgroup of up to 20-25% of all RCCs. Advances in histopathology and molecular genetics, together with evidence gained from retrospective and prospective clinical data, have improved understanding of these tumors in recent years. Nevertheless, selective trials of current and novel therapies including new targeted agents in patients with nccRCC are urgently needed to further improve treatment guidelines.

[Histological subtypes of renal cell carcinoma : Overview and new developments]

BACKGROUND

The classification of renal cell carcinoma (RCC) has changed remarkably in recent years.

OBJECTIVES

This is a short overview of the classification of RCC, focusing on new developments.

MATERIALS AND METHODS

A literature search was performed resulting in an overview of the classification of RCC. Emerging entities were discussed in detail.

RESULTS

Apart from the RCC subtypes in the WHO classification of 2016, several emerging entities came up over the last few years that are characterized by typical morphology, immunophenotype, and especially specific genetic alterations.

CONCLUSION

Precise classification of RCC is the key to better prognostic assessment with potential tumor-specific therapy and plays an important role in the recognition of possible association with hereditary tumor syndromes.

SETD2, GIGYF2, FGFR3, BCR, KMT2C, and TSC2 as candidate genes for differentiating multilocular cystic renal neoplasm of low malignant potential from clear cell renal cell carcinoma with cystic change

Purpose

Multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) and clear cell renal cell carcinoma with cystic change (MCRCC) have different prognoses despite similar histologic characteristics. The aim of this study was to identify differentially mutated genes in resected tumor specimens from patients diagnosed with MCRNLMP and MCRCC using a kidney cancer gene panel.

Materials and Methods

Between 2009 and 2016, 13 MCRNLMP and 17 MCRCC cases were selected. Tumor tissues from 5 MCRNLMP and 16 MCRCC cases were subjected to gene sequencing to detect mutations among 88 genes selected from a kidney cancer gene panel after quality control. Fisher's exact test was used to compare gene mutation profiles between the two diseases. Genes were considered to be positive for mutation according to the presence of an in-frame/frameshift deletion or insertion, missense/nonsense mutation, or multi-hit mutation.

Results

During a median follow-up period of 66.2 months, there was only one case of MCRCC recurrence among all 30 patients. Target gene sequencing showed that 35 genes tended to be more frequently positive in either disease group, with six genes showing a significantly different frequency of mutation between the groups: GIGYF2 (odds ratio [OR], 5.735), FGFR3 (OR, 6.787), SETD2 (OR, 4.588), BCR (OR, 6.266), KMT2C (OR, 8.167), and TSC2 (OR, 4.474).

Conclusions

Six candidate genes showed significantly different mutation patterns between MCRNLMP and MCRCC, providing insight into their pathogenic mechanisms and differential prognoses.

Clear cell papillary renal cell carcinoma: A case report and review of the literature

Clear cell papillary renal cell carcinoma (ccpRCC) was recently established as a distinct type of epithelial neoplasm by the International Society of Urological Pathology Vancouver Classification of Renal Neoplasia. Here, we report a case of partial nephrectomy for a ccpRCC detected during the routine follow-up of a previously treated liposarcoma in a 70-year-old male patient. The patient was referred to the urology department for a right-sided renal mass (size: 2 cm) detected during routine annual imaging follow-up for a malignant right inguinal fibrous histocytoma and liposarcoma that had been diagnosed 6 and 4 years earlier, respectively, and treated with surgery and adjuvant radiation therapy. Following partial nephrectomy, the renal mass was pathologically diagnosed as ccpRCC, and immunohistochemistry revealed carbonic anhydrase 9 (CA9) expression. No recurrences or metastases were detected on follow-up imaging for 6 months. This is the first report of partial nephrectomy for incidentally discovered CA9-positive ccpRCC.

Tumour heterogeneity in triplet-paired metastatic tumour tissues in metastatic renal cell carcinoma: concordance analysis of target gene sequencing data

AIMS

The aim of the present study was to determine the concordant correlation in the expression of 88 target genes from triple-paired metastatic tissues in individual patients with metastatic renal carcinoma (mRCC) using a target gene sequencing (TGS) approach.

METHODS

Between 2002 and 2017, a total of 350 triple-paired metastatic tissue samples from 262 patients with mRCC obtained from either nephrectomy or metastasectomy were used for TGS of 88 candidate genes. After quality check, 243 tissue samples from 81 patients were finally applied to TGS. The concordance of triple-paired tissues was analysed with the 88 TGS panels using bioinformatics tools.

RESULTS

Among 81 patients, alterations were observed in 42 (51.9%) for any of the 88 mRCC panel genes; however, no pathogenic gene was detected in 38 (39.5%) . Concordance >95% for altered gene expression among the three tissues was reported in 12 (28.6%) patients, while concordance >95% within two tissues was reported in 30 (71.4%); concordance <50% was reported in the remaining eight patients. Considering several types of genetic alterations, including deletions, insertions, missense and nonsense mutations, and splice variants, genes most frequently detected with genetic alterations in the patients with mRCC were PTEN loss, followed by FLCN, BCR, SMARCA2, AKAP9, MLH1, MYH11, APC and TP53.

CONCLUSIONS

The study provides reference information on the genetic alterations at various organ sites and the multi-heterogeneity of mRCC tissues. The concordance of pathogenic gene alterations within tissues was not high, and approximately half of the patients showed no pathogenic gene alterations at all.

Immune checkpoint inhibitors in renal cell carcinoma

The immune system has long been known to play a critical role in the body's defence against cancer, and there have been multiple attempts to harness it for therapeutic gain. Renal cancer was, historically, one of a small number of tumour types where immune manipulation had been shown to be effective. The current generation of immune checkpoint inhibitors are rapidly entering into routine clinical practice in the management of a number of tumour types, including renal cancer, where one drug, nivolumab, an anti-programmed death-1 (PD-1) monoclonal antibody (mAb), is licensed for patients who have progressed on prior systemic treatment. Ongoing trials aim to maximize the benefits that can be gained from this new class of drug by exploring optimal timing in the natural course of the disease as well as combinations with other checkpoint inhibitors and drugs from different classes.

[Succinate dehydrogenase (SDH)-deficient renal cell carcinoma]

Succinate dehydrogenase (SDH) represents a type II mitochondrial complex related to the respiratory chain and Krebs cycle. The complex is composed of four major subunits, SDHA, SDHB, SDHC and SDHD. The oncogenic role of this enzyme complex has only recently been recognized and the complex is currently considered an important oncogenic signaling pathway with tumor suppressor properties. In addition to the familial paraganglioma syndromes (types 1-5) as prototypical SDH-related diseases, many other tumors have been defined as SDH-deficient, in particular a subset of gastrointestinal stromal tumors (GIST), rare hypophyseal adenomas, a subset of pancreatic neuroendocrine neoplasms (recently added) and a variety of other tumor entities, the latter mainly described as rare case reports. As a central core subunit responsible for the integrity of the SDH complex, the expression of SDHB is lost in all SDH-deficient neoplasms irrespective of the specific SDH subunit affected by a genetic mutation in addition to concurrent loss of the subunit specifically affected by genetic alteration. Accordingly, all SDH-deficient neoplasms are by definition SDHB-deficient. The SDH-deficient renal cell carcinoma (RCC) has only recently been well-characterized and it is included as a specific subtype of RCC in the new World Health Organization (WHO) classification published in 2016. In this review, the major clinicopathological, immunohistochemical and genetic features of this rare disease entity are presented and discussed in the context of the broad differential diagnosis.

Adult Renal Cell Carcinoma: A Review of Established Entities from Morphology to Molecular Genetics

According to the current World Health Organization (WHO), renal cell carcinomas (RCCs) that primarily affect adults are classified into 8 major subtypes. Additional emerging entities in renal neoplasia have also been recently recognized and these are discussed in further detail by Mehra et al (Emerging Entities in Renal Neoplasia, Surgical Pathology Clinics, 2015, Volume 8, Issue 4). In most cases, the diagnosis of a RCC subtype can be based on morphologic criteria, but in some circumstances the use of ancillary studies can aid in the diagnosis. This review discusses the morphologic, genetic, and molecular findings in RCCs previously recognized by the WHO, and provides clues to distinction from each other and some of the newer subtypes of RCC. As prognosis and therapeutic options vary for the different subtypes of RCC, accurate pathologic distinction is critical for patient care.