Cystic clear cell papillary renal cell carcinoma: is it related to multilocular clear cell cystic neoplasm of low malignant potential?

Vascular, adipose tissue, and/or calyceal invasion in clear cell tubulopapillary renal cell tumour: potentially problematic diagnostic scenarios

AIMS

The 2022 WHO classification for kidney tumours recently downgraded clear cell tubulopapillary (also known as clear cell papillary) renal cell carcinoma (RCC) to a benign neoplasm (i.e. clear cell tubulopapillary renal cell tumour) based on the overwhelmingly banal nature of this neoplasm. However, it has been recognized that some clear cell tubulopapillary renal cell tumours demonstrate vascular, adipose or pelvicalyceal invasion, raising the possibility of more aggressive behaviour. The goal of this study was to determine if these 'high stage' features have an effect on tumour prognosis, warranting a carcinoma designation.

METHODS AND RESULTS

After excluding cases with tissue artefact (i.e. prior core biopsy track changes) and other RCC subtypes with next-generation sequencing, nine clear cell tubulopapillary renal cell tumours with these so-called 'high stage' features, and otherwise classic morphologic and immunophenotypic findings, including low-grade cytology and 'cup-like' CA9 expression, were evaluated. Median tumour size was 2.2 cm with a range of 0.8 to 6.7 cm. Eight cases (89%) demonstrated perinephric or hilar adipose tissue invasion, although most of these cases showed a bulging (in contrast to an infiltrative) growth pattern. One case demonstrated renal vascular invasion in addition to hilar adipose tissue invasion, and one case demonstrated extension into the pelvicalyceal system. There were no recurrences or evidence of metastatic disease.

CONCLUSION

These overall findings continue to support the benign designation for clear cell tubulopapillary renal cell tumours, despite morphologic features that might raise the possibility of a 'higher stage' neoplasm.

Multicystic Clear Cell Renal Tumors With Low-grade Nuclear Features: Time to Include TFE3 Translocation-associated Carcinomas

TFE3 -rearranged renal cell carcinoma (RCC) is a distinct, uncommon entity with more than 20 different fusion partners identified; however, histomorphology may be suggestive of specific fusion partners in select TFE3 -rearranged RCCs. For example, most MED15 :: TFE3 fusion associated RCCs exhibit multilocular cystic morphology, mimicking multilocular cystic renal neoplasm of low malignant potential. Here we present a case of MED15 :: TFE3 RCC in an older adult and review the literature with an emphasis on practical diagnostic approaches for predominantly cystic, low-grade, clear cell renal tumors.

Clear cell renal cell carcinoma with cystic component similar to multilocular cystic renal neoplasm of low malignant potential: a rare pattern of cyst-dependent progression from multilocular cystic renal neoplasm of low malignant potential

BACKGROUND

For clear cell renal cell carcinoma (ccRCC) with cystic component similar to multilocular cystic renal neoplasm of low malignant potential (MCRN-LMP) and solid low-grade component simultaneously, we propose the designation "ccRCC with cystic component similar to MCRN-LMP" and to study the relationship between MCRN-LMP and it.

METHODS

Twelve cases of MCRN-LMP and 33 cases of ccRCC with cystic component similar to MCRN-LMP were collected from 3,265 consecutive RCCs to compare them in clinicopathological features, immunohistochemical findings (PAX8, CA-IX, CK7, Vimentin, CD10, P504s, TFE3, 34βE12) and prognosis.

RESULTS

There was no significant difference in age, sex ratio, tumor size, treatment, grade and stage between them (P > 0.05). All ccRCCs with cystic component similar to MCRN-LMP coexisted with MCRN-LMP and solid low-grade ccRCCs, and MCRN-LMP component ranged from 20 to 90% (median, 59%). The positive ratio of CK7 and 34βE12 in MCRN-LMPs and ccRCCs' cystic parts was significantly higher than that in ccRCCs' solid parts, but the positive ratio of CD10 in MCRN-LMPs and ccRCCs' cystic parts was significantly lower than that in ccRCCs' solid parts (P < 0.05). There was no significant difference of all immunohistochemistry profiles between MCRN-LMPs and ccRCCs' cystic parts (P > 0.05). No patient developed recurrence or metastasis.

CONCLUSIONS

MCRN-LMP and ccRCC with cystic component similar to MCRN-LMP have similarity and homology in clinicopathological features, immunohistochemical findings and prognosis, and form a low-grade spectrum with indolent or low malignant potential behavior. The ccRCC with cystic component similar to MCRN-LMP may be a rare pattern of cyst-dependent progression from MCRN-LMP.

Clear Cell Papillary Renal Cell Tumors: A Study of 42 Tumors with Emphasis on the Fibrous Capsule, Cystic Component, and GATA3 Immunohistochemistry

Clear cell papillary renal cell tumor is a common and sometimes underdiagnosed renal cell neoplasm. Its proper recognition is important because its diagnosis implies a remarkably high probability of indolent behavior. This study aimed to evaluate the frequency of a fibrous capsule, a cystic component, and a GATA3 expression in clear cell papillary renal cell tumors. We assessed 419 renal cell neoplasms from three institutions located in northeastern Brazil and identified 42 clear cell papillary renal cell tumors (from 39 patients), which were the fourth most common renal cell neoplasm. These tumors commonly exhibited fibrous capsules (all showed complete or partial capsules) and cystic component (93%). Eighteen out of 42 tumors (43%) showed some expression of GATA3, and weak and focal staining was common among the positive tumors. Clear cell papillary renal cell tumor must always be included in the differential diagnosis of predominantly cystic renal cell neoplasms. As GATA3 is inconsistently expressed in clear cell papillary renal cell tumors, it is not useful in this diagnosis.

A Sarcomatoid Renal Cell Carcinoma with Clear Cell Papillary-Like Primary Tumor and Lymph Node Metastasis: A Diagnostic Conundrum

Clear cell papillary renal cell tumor (CCPRCT) is a distinct clinical entity with characteristic pathological features and non-aggressive clinical behavior. Diagnostically challenging cases present when there are immunomorphological findings of CCPRCT associated with heterogeneous morphologies, aggressive histological features, and advanced pathological stages-so-called CCPRCT-like tumors. In this report, we describe a heterogeneous, multifocal renal tumor with immunomorphological characteristics of CCPRCT but with associated aggressive features such as sarcomatoid and necrotic areas, perirenal and sinus fat involvement, and most notably, lymph node metastasis composed entirely of classic CCPRCT morphology and immunophenotype. Immunohistochemical and fluorescence in situ hybridization studies did not support a translocation renal cell carcinoma. Molecular analyses did not identify common mutations or chromosomal abnormalities seen in clear cell renal cell carcinoma or ELOC-mutated renal cell carcinoma. This case highlights that rare renal cell tumors remain difficult to classify and the distinction between CCPRCT and CCPRCT-like tumors remains to be better defined.

Renal Cell Carcinoma in End-Stage Renal Disease: A Review and Update

Renal cell carcinoma (RCC) occurring in the setting of end-stage renal disease (ESRD) shows unique clinicopathological characteristics. The two most frequent types of ESRD-associated RCC are acquired cystic kidney disease-associated renal cell carcinoma (ACKD-RCC) and clear-cell papillary renal cell carcinoma (ccpRCC). Other types of RCC also occur in ESRD, albeit with different frequencies from the non-ESRD general population. The histological features of RCC do not vary in the setting of ESRD vs. non-ESRD, yet other findings, such as multifocality and multiple tumor types, are more frequent in ESRD. Studies have generated novel and important knowledge of the etiology, epidemiology, diagnosis, treatment, immunophenotype, and molecular characteristics of ESRD-associated RCC. Knowledge of these data is important for both pathologists and other physicians who may encounter ESRD patients with RCC. This review presents a comprehensive summary and update of the literature on RCC in ESRD, with a focus on the two most frequent types, ACKD-RCC and ccpRCC.

Classification of renal cell tumors – current concepts and use of ancillary tests: recommendations of the Brazilian Society of Pathology

Classification of renal cell carcinomas has become more challenging. The 2016 WHO classification included 14 different subtypes and 4 emerging/provisional entities, and recent literature indicates new entities to be incorporated. Nomenclature is based on cytoplasmic appearance, architecture, combination of morphologies, anatomic location, underlying disease, familial syndromes, and specific genetic alterations. Immunohistochemistry is useful in selected cases while it can be insufficient in entities that require molecular confirmation of a specific gene alteration. The aim of these recommendations is to provide a reasonable and optimized approach for the use of ancillary tests in subtyping renal tumors, particularly in resource-limited settings.

Clear cell papillary renal cell carcinoma: an update after 15 years

Fifteen years since the first recognition of clear cell papillary renal cell carcinoma, this distinct renal tumour type is now well accepted as a distinct entity in major classification schemes. It occurs both with and without end-stage renal disease and may be multifocal or bilateral in both scenarios. Recognisable morphological features include clear cells lining branching glands and variable papillary formations with nuclear alignment. Most tumours are small (pT1a) and nucleolar grade 1-2. Immunohistochemistry consistently shows positivity for carbonic anhydrase IX and cytokeratin 7, and often high molecular weight cytokeratin or GATA3, the latter suggesting distal nephron phenotype. Labeling for AMACR and CD10 is consistently negative or minimal. Despite a resemblance to clear cell renal cell carcinoma, molecular alterations of VHL and chromosome 3p are typically lacking, with debatable rare exceptions. Potential mimics include clear cell renal cell carcinoma (with branching architecture or nuclear alignment), papillary renal cell carcinoma with clear cytoplasm, or rarely MITF family translocation renal cell carcinoma. Clinical behaviour is highly favourable with rare, debatable reports of aggressive behaviour. Combined with striking similarity to several extrarenal benign neoplasms, it would be reasonable to reclassify this entity as a benign or low malignant potential neoplasm. Using the nomenclature of the extrarenal counterparts, clear cell papillary (cyst)adenoma is proposed.

Clear Cell Papillary Renal Cell Carcinoma: A Recent Entity With Distinct Imaging Patterns

OBJECTIVE. Clear cell papillary renal cell carcinoma (RCC), an entity with strikingly indolent behavior, recently was added to the World Health Organization classification of renal tumors and represents the fourth most common histologic type of renal cell carcinoma. This article aims to describe the imaging features of clear cell papillary RCC along with its clinical and pathologic characteristics. MATERIALS AND METHODS. This retrospective study consisted of 27 patients with 44 clear cell papillary RCC tumors. The inclusion criteria were a pathologically proven clear cell papillary RCC and the availability of preoperative imaging including at least CT or MRI. Two experienced radiologists performed the imaging analysis independently. RESULTS. Patients (mean age, 62 years old) presented with renal failure in 26% of cases, and four had a tumor-predisposing disease. Multiple clear cell papillary RCC tumors occurred in 5 of the 27 patients. Two imaging patterns were recognizable. Solid clear cell papillary RCC (n = 23, 52%) presented as heterogeneous tumors with minor cystic changes (74%) and rarely exhibited calcifications (10%). All solid tumors showed hyperintensity on T2-weighted images compared with renal cortex and maximal enhancement on corticomedullary phase with a delayed washout. Cystic clear cell papillary RCC (n = 21, 48%) were classified as Bosniak IV (57%), III (33%), or IIF (10%), with a predominant unilocular pattern (76%). Pathologic stage according to TNM classification was mostly pT1a and low grade on nucleolar grade. All patients were alive at the date of last follow-up after treatment with no metastasis or recurrence. CONCLUSION. Clear cell papillary RCC exhibits two imaging patterns including cystic and solid in almost equal proportion. Imaging characteristics of solid clear cell papillary RCC including high signal T2 intensity and early arterial enhancement are unexpectedly distinct from papillary RCC and very similar to clear cell RCC.

Reactivity of CK7 across the spectrum of renal cell carcinomas with clear cells

AIMS

Current available data on cytokeratin 7 (CK7) immunostaining pattern in the clear cell renal cell carcinoma (RCC) spectrum is conflicting. The aim of this study was to assess CK7 immunoreactivity within the spectrum of clear cell renal neoplasms, including clear cell RCC, multicystic renal neoplasm of low malignant potential and clear cell papillary RCC-like tumours.

METHODS AND RESULTS

We analysed two clones of CK7 and two tumour blocks for a total of 75 cases divided into five distinct groups: (i) low-grade clear cell RCC, (ii) high-grade clear cell RCC, (iii) multicystic renal neoplasm of low malignant potential, (iv) clear cell RCC with cystic changes and (v) clear cell papillary RCC-like tumours. We found the highest CK7 reactivity in low-grade clear cell RCC, multicystic renal neoplasm of low malignant potential and clear cell papillary RCC-like groups, ranging from 60% to 93%.

CONCLUSIONS

Our findings show that CK7 immunoreactivity in clear cell RCC is variable, and the extent of staining depends on the grade and architectural growth patterns of the tumours.

New entities, new technologies, new findings: A review of the cytologic features of recently established subtypes of renal cell carcinoma

Several new renal tumor types with distinctive pathologic, epidemiologic, and genetic signatures have recently been adopted in the fourth edition of the World Health Organization classification. In succeeding years, the cytologic features of most of these new types have been described, adding to the trend of increasing diagnostic accuracy for most common renal cell carcinoma subtypes and the important diagnostic role of cytologic sampling in the management and personalization of therapy. The current article reviews the cytologic findings from these recently established renal cell carcinoma subtypes. Emphasis is placed on cytologic diagnostic clues, confirmatory ancillary testing, salient differential diagnoses, and challenges that can be encountered in an attempt to render accurate interpretations in small samples.

Validation of 34betaE12 immunoexpression in clear cell papillary renal cell carcinoma as a sensitive biomarker

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently recognised neoplasm with a broad spectrum of morphological characteristics, thus representing a challenging differential diagnosis, especially with the low malignant potential multicystic renal cell neoplasms and clear cell renal cell carcinoma. We selected 14 cases of CCPRCC with a wide spectrum of morphological features diagnosed on morphology and CK7 immunoreactivity and analysed them using a panel of immunohistochemical markers, focusing on 34βE12 and related CKs 1,5,10 and 14 and several molecular analyses such as fluorescence in situ hybridisation (FISH), array comparative genomic hybridisation (aCGH), VHL methylation, VHL and TCEB1 sequencing and multiplex ligation-dependent probe amplification (MLPA). Twelve of 13 (92%) CCPRCC tumours were positive for 34βE12. One tumour without 3p alteration by FISH revealed VHL mutation and 3p deletion at aCGH; thus, it was re-classified as clear cell RCC. We concluded that: (1) immunohistochemical expression of CK7 is necessary for diagnostic purposes, but may not be sufficient to identify CCPRCC, while 34βE12, in part due to the presence of CK14 antigen expression, can be extremely useful for the recognition of this tumour; and (2) further molecular analysis of chromosome 3p should be considered to support of CCPRCC diagnosis, when FISH analysis does not evidence the common loss of chromosome 3p.

Cytomorphology of clear cell papillary renal cell carcinoma

BACKGROUND

Clear cell papillary renal cell carcinoma (CCPRCC) shares some morphologic and immunohistochemical markers with clear cell RCC and papillary RCC. To the author's knowledge, its cytomorphology on fine-needle aspiration (FNA) or touch preparations (TPs) of core needle biopsy specimens has not been well delineated in the English language literature.

METHODS

The FNA/TP cytomorphology of 7 retrieved cases was studied.

RESULTS

The tumor cells were arranged in small nests (100%), 3-dimensional clusters (71%), papillary/tubular/acinar arrays (43%), and as single cells (57%). The tumor cells were columnar (100%) and polygonal (57%) in shape, with eccentric, small, round-to-oval nuclei. The nuclei contained evenly distributed, fine granular chromatin and demonstrated a smooth nuclear membrane (100%) (Fuhrman grade 1 to 2). The tumor cells had a moderate amount of delicate or clear cytoplasm containing small vacuoles (100%) and ill-defined cytoplasmic borders (100%). Scattered macrophages (57%) and necrosis (29%) were identified in the background. Vessels were noted within the papillary cores, transversing or surrounding nests of tumors. Immunochemical studies demonstrated expression of cytokeratin 7 (CK7) (100%), carbonic anhydrase IX (CA 9) (100% in a cup-shaped membranous pattern), α-methylacyl-CoA racemase (AMACR) (50%), and CD10 (43%). The tumor cells were negative for CD117.

CONCLUSIONS

CCPRCC was found to demonstrate cytologic features that when taken together are helpful in diagnosing CCPRCC on FNA smears and TPs. If core needle biopsy specimens or cell blocks are available, an immunohistochemical panel including CK7, CA IX, CD10, and AMACR may help in excluding congeners. This subtype of RCC requires differentiation from clear cell RCC and papillary RCC due to its low-grade indolent behavior. Cancer Cytopathol 2017;125:48-54. © 2016 American Cancer Society.