Reclassifying Papillary, Oncocytic and Chromophobe Renal Tumours Based on the 5 < sup > th < /sup > Who Classification 2022

OBJECTIVE

The classification of renal tumors is expanding with the addition of new molecular entities in the 5th World Health Organization classification. Apart from this, the major updates in the definition of papillary renal cell carcinoma are that these tumors are no longer subtyped into type 1 and type 2. In oncocytic tumors, the new molecularly defined renal tumors, emerging and novel entities need to be considered in the diagnosis of oncocytic and chromophobe renal tumors.

MATERIAL AND METHODS

This is a retrospective study to review and reclassify papillary, oncocytic, and chromophobe renal tumors based on the new WHO classification and correlate with clinical data, gross, microscopic features, and immunohistochemistry markers.

RESULTS

A total of thirteen cases were reviewed and the tumor grade was changed for three out of four cases of papillary renal cell carcinoma and a single case was recategorized and graded. In nine cases of oncocytic and chromophobe renal tumors, the diagnoses were modified in 3 cases.

CONCLUSION

Newly defined molecular renal tumors require advanced immunohistochemistry markers and molecular tests. This poses diagnostic challenges to pathologists practicing in low resource settings where molecular tests are not available.

Hürthle (Oncocytic) Cell Tumors of Thyroid: Etiopathogenesis, Diagnosis and Clinical Significance

The etiopathogenesis and the classification of oncocytic (Hurthle cell) tumors of the thyroid is reviewed with an emphasis on the role played by mitochondrial and nuclear genetic abnormalities that interfere with mitochondrial function. Oxyphilia is classified into primary or secondary and the so-called Hurthle cell carcinoma is divided into oncocytic (Hurthle cell) variants of papillary and follicular carcinoma.

Papillary tumor of the pineal region and spindle cell oncocytoma of the pituitary: new tumor entities in the 2007 WHO Classification

We have reviewed the features of two recently described intracranial tumors, which have been formally recognized as distinct entities by the 2007 WHO Classification of Brain Tumours: Papillary tumor of the pineal region and spindle cell oncocytoma of the pituitary gland. Their salient clinicopathological features, differential diagnosis, histogenetic hypothesis and outcome are discussed.

Expression of CD138 (Syndecan-1) in renal cell carcinoma is reduced with increasing nuclear grade

CD138/Syndecan-1 is a cell-surface heparan sulfate proteoglycan expressed on most epithelial cells, and decreased CD138 expression is associated with increased invasive and metastatic potential in carcinomas. CD138 expression has not been investigated previously in renal neoplasms. Formalin-fixed, paraffin-embedded tissue sections of 50 renal cell carcinomas (RCCs) (40 clear-cell RCCs of various nuclear grades, 10 of which harbored metastases; 6 papillary RCCs, 4 chromophobe RCCs) and 4 oncocytomas were stained immunohistochemically for CD138 using the monoclonal antibody B-B4 (CD138). Staining intensity and distribution were scored and results related to histologic type, nuclear grade, and local stage (pT). Immunoreactivity was membranous in all clear-cell RCCs, chromophobe RCCs, and oncocytomas and was located at the basal aspect of cytoplasm in papillary RCCs. In clear-cell RCCs, the extent of CD138 immunoreactivity decreased with increasing nuclear grade (P<0.001). No significant correlation was found between CD138 immunoreactivity and histologic type (P=0.2) or local stage (P=0.7). Metastatic foci showed a mild to moderate decrease in intensity compared with primary tumor. Decreased expression of CD138 may have a role in more aggressive behavior of clear-cell RCC.

Pathological Features of Renal Neoplasms Classified by Size and Symptomatology

PURPOSE

We examined the relationship between tumor size and pathological findings in a contemporary series of surgical renal lesions and we characterized the relationship of incidental and symptomatic tumors to pathological findings.

MATERIALS AND METHODS

We retrospectively reviewed the records of patients treated surgically for renal lesions suspicious for malignancy between March 2000 and May 2005. Specimens were examined for a gross and microscopic description. Statistical analysis was used to determine the correlation of size and symptomatology.

RESULTS

A total of 349 renal masses from 331 patients were identified. Of the 349 renal masses 56 (16.0%) were benign, 289 (82.8%) were renal cell carcinoma and 4 (1.1%) were other malignancies. The percent of malignant tumors increased from 72.1% for those less than 2 cm to 93.7% for those greater than 7 cm (OR 1.39, 95% CI 1.17 to 1.65). Of the 349 renal masses 258 (73.9%) were discovered incidentally and 91 (26.1%) were symptomatic. Mean size of incidental and symptomatic tumors was 3.7 and 6.2 cm, respectively (p < 0.001). When comparing T1 incidental and symptomatic tumors, there was no significant difference in the overall frequency of malignancy. When comparing T2 incidental and symptomatic tumors, the groups had similar malignancy rates (90.9% and 100%, respectively, p = 0.16). However, symptomatic lesions showed an increased incidence of high grade malignancy (78.4% vs 40.9%, p = 0.012).

CONCLUSIONS

Smaller renal tumors are more likely to be benign or be a lower grade of malignancy. T1 renal tumors are more likely to be detected incidentally than T2 tumors. When T1 incidental and symptomatic tumors were compared, there was no difference between the malignancy rates. However, when T2 incidental and symptomatic tumors were compared, symptomatic tumors were more likely to be high grade malignancy.

Subclinical adenomas in postmortem pituitaries: classification and correlations to clinical data

OBJECTIVE

The aim of this study was to examine pituitary adenomas in a series of postmortem pituitaries by use of modern technologies of immunostaining, to classify the adenomas according to the current WHO classification and to analyse the possible associations to the available clinical data.

METHODS

In this study, pituitaries of 3048 autopsy cases obtained from autopsy series of the years 1991-2004 were examined.

RESULTS

A total of 334 pituitary adenomas were found in 316 pituitaries. One hundred and thirty-two sparsely granulated prolactin cell adenomas (39.5%), 75 null cell adenomas (22.5%) and 31 oncocytomas were diagnosed. Forty-six ACTH cell adenomas (13.8%, 27 densely granulated, 19 sparsely granulated) and one adenoma composed of Crooke's cells were detected. Twenty-two gonadotroph cell adenomas (6.6%), seven GH cell adenomas (four sparsely granulated, three densely granulated), one mixed GH cell-PRL cell adenoma, two TSH cell adenomas, five plurihormonal adenoma type I, four plurihormonal adenoma type II and two alpha-subunit-only adenomas were seen. Six adenomas remained unclassified because the tissue was not contained in all sections for immunohistochemistry. Seventeen pituitaries included multiple tumours. The overall tumour size ranged from 0.1 to 20 mm in diameter. Among 76 adenomas (22.7%), which had a tumour size of > or = 3 mm, only three tumours were macroadenomas corresponding to a tumour size of more than 10 mm. The evaluation of the available clinical data showed 99 cases of hypertension, 65 cases of diabetes mellitus, six patients with hyperthyroidism and four with hypothyroidism. No symptoms of adenohypophyseal hormone hypersecretion were reported. The statistical correlations to clinical data were discussed.

CONCLUSIONS

Adenomas in postmortem pituitaries differ from those in surgical series in proportion of adenoma types and biological behaviour.

Karunkeltumor unklarer Dignität

CASE REPORT

A sixty year old woman presented with a tumor of the caruncle that had persisted for one year. Ophthalmologic history was unremarkable. Physical examination disclosed an indolent, tight elastic, highly vascularizated tumor. The lesion measured five millimeter in diameter. Histopathology revealed tall columnar cells with small round nuclei. The cytoplasm stained positive with hematoxylin and eosin. The typical histopathologic features were consistent with an oncocytoma.

CONCLUSION

Tumors of the caruncle are very heterogenous because the caruncle contains tissues of the conjunctiva and the epidermis. Therefore to exclude a malignant process an excisional biopsy should always be performed even so in general tumors of the caruncle are benign. The most frequent tumors of the caruncle are papilloma, nevi, pyogenic granuloma, epithelial inclusion cyst and chronic inflammation. In only 4 % of the cases oncocytomas are found even the oncocytoma is considered to be a typical tumor of the caruncle.

Is patient's age a prognostic factor for follicular thyroid carcinoma in the TNM classification system?

The knowledge of prognostic factors is essential for an optimal treatment of patients. The aim of our study was to find out if age is an independent prognostic factor for patients with follicular or Hürthle cell carcinoma. This retrospective study was carried out in 261 patients (median age, 62 years) with follicular or Hürthle cell thyroid carcinoma treated at our institute from 1972-2002. For all patients the follow-up was performed at our institute at least once per year. The data on gender and age of the patients, disease history, extent of disease, morphologic characteristics, mode of therapy, outcome, and survival were collected. Statistical correlation between possible prognostic factors and cause-specific survival was analyzed by univariate and Cox's multivariate survival analysis. The 10-year and 20-year survival of all 261 patients were 70% and 42%, respectively. Even 10 of 49 (20%) of our patients who were under 45 years of age (i.e., in stage II of the tumor, node, metastases [TNM] classification system) died of disease. Multivariate analysis showed that primary tumor size and distant metastases were independent prognostic factors for survival. Lymph node metastases as well as the age of patients were not found to be independent prognostic factors. Therefore, the patients with distant metastases or tumor stage T4 who are under 45 years of age cannot be considered to have favorable prognosis.

The diagnostic utility of MOC31, BerEP4, RCC marker and CD10 in the classification of renal cell carcinoma and renal oncocytoma: an immunohistochemical analysis of 328 cases

AIMS

To demonstrate the diagnostic utility of MOC31, BerEP4, renal cell carcinoma marker (RCC Ma) and CD10 in the classification of RCC and renal oncocytoma, based upon a comprehensive immunohistochemical analysis.

METHODS AND RESULTS

Immunohistochemistry was performed on 328 samples consisting of 256 clear cell/conventional, 27 papillary, 28 chromophobe, five collecting duct, five unclassified RCCs and seven renal oncocytomas using antibodies MOC31, BerEP4 and antibodies against cytokeratins (KL-1, CAM5.2, 34betaE12, cytokeratin 7), RCC Ma, epithelial membrane antigen, E-cadherin, CD10, CD15 and vimentin. Multivariate analysis showed that MOC31, BerEP4, RCC Ma and CD10 have discriminatory value. MOC31 and BerEP4 chiefly labelled distal tubules of normal kidney while RCC Ma and CD10 labelled the proximal tubules. Twenty-three chromophobe RCCs (82%) were reactive for MOC31, while only four clear cell RCCs and three papillary RCCs were positive for this marker. Clear cell RCCs were characterized by a high positive rate for CD10 (82%) and a low positive rate for BerEP4 (27%). Papillary RCCs frequently coexpressed RCC Ma and BerEP4 (51%). All renal oncocytomas were negative for MOC31 and CD10.

CONCLUSIONS

MOC31 has diagnostic merit in discerning chromophobe RCC. The CD10+/BerEP4- profile and RCC Ma+/BerEP4+ profile achieve moderate sensitivity and good specificity for clear cell RCC and papillary RCC, respectively. The non-reactivity for both MOC31 and CD10 is helpful in distinguishing renal oncocytoma from RCC. When properly selected, antibodies have immunohistochemical diagnostic utility for the classification of renal cortical epithelial tumours.

RET rearrangements in archival oxyphilic thyroid tumors: New insights in tumorigenesis and classification of Hürthle cell carcinomas?

BACKGROUND

Oncocytic carcinomas (Hürthle cell carcinomas [HCCs]) are commonly considered a subgroup of follicular thyroid carcinomas (FTCs). Recent characterization of a subgroup of "Hürthle cell" papillary thyroid carcinomas (PTCs) was based on the identification of PTC-specific RET hybrid oncogenes in HCCs.

METHODS

We examined 27 HCCs, 4 oxyphilic FTCs, 5 oxyphilic PTCs, 2 poorly differentiated carcinomas arising from HCCs (HCC-UTCs), and 16 oxyphilic adenomas. Total RNA was extracted from paraffin-embedded thyroid neoplasms by a novel macrodissection technique that uses a cylindric punch. After reverse transcription-polymerase chain reaction-based screening for RET rearrangements, the samples were tested for all known RET/PTC 1 to 11 hybrids with the use of artificially constructed chimeric sequences as controls.

RESULTS

The elimination of C cells by punching dissection significantly reduced RET wild-type expression. RET hybrid oncogenes (7x RET/PTC1, 1x RET/PTC1L, 2x RET/PTC3, 5 uncharacterized RET/PTCx) were demonstrated in 7 of 27 HCCs, in 0 of 4 oxyphilic FTCs, in 4 of 5 oxyphilic PTCs, in 1 of 2 HCC-UTCs, and in 3 of 16 oxyphilic adenomas.

CONCLUSION

Our results suggest that the expression of rearranged RET hybrid oncogenes (1) is present in a similar percentage of HCCs when compared with the literature on nonoxyphilic PTCs, (2) defines PTC-like HCCs better than histomorphologic characterization, (3) excludes HCCs as a subgroup of FTCs, and (4) may play a role in the early tumorigenesis of oncocytic tumors.

Subclassification of renal cell neoplasms: an update for the practising pathologist

The classification of renal cell neoplasms has been extensively studied in the last decade, and a standardized nomenclature adopted. Although this system is based on a combination of genetic, histological and immunohistological features, in most cases accurate classification can be based on histological features alone. This review summarizes the key features of the tumours included in this system, and then focuses on diagnostic difficulties that can arise when using this system, as well as reviewing several recently characterized tumours that are not yet included.

Hürthle cell tumors: using molecular techniques to define a novel classification system

BACKGROUND

Since ret/PTC gene rearrangements are specific to papillary thyroid carcinoma (PTC), the diagnosis of Hürthle cell PTC (HCPTC) has recently been expanded to include a subset of Hürthle cell tumors (HCTs) that may lack both papillary architecture and/or classic nuclear features but that harbor a ret/PTC gene rearrangement. We hypothesize that such HCPTCs behave in a fashion analogous to other papillary carcinomas, while Hürthle cell carcinomas (HCCs) behave similarly to follicular carcinomas.

EDUCATIONAL OBJECTIVES

At the conclusion of this article, participants should be able to discuss HCTs and to identify HCPTCS using molecular techniques.

METHODS

A retrospective chart review was carried out on 56 patients with HCTs. All pathological specimens were analyzed for ret/PTC gene rearrangements. Hürthle cell adenoma (HCA) was defined as an HCT that did not exhibit capsular and/or vascular invasion and that lacked a ret/PTC gene rearrangement when evaluated by immunohistochemical and reverse transcription polymerase chain reaction analysis. An HCC was defined as an HCT with capsular and/or vascular invasion that lacked a ret/PTC gene rearrangement, and an HCPTC was defined as any HCT that harbored a ret/PTC gene rearrangement.

RESULTS

The subclassification of the 56 HCTs was as follows: 21 HCAs, 15 HCCs, and 20 HCPTCs. No patients with HCA or HCC were ret/PTC positive. Five of the 6 patients with definite lymph node metastasis were in the HCPTC group, demonstrating that molecular analysis helps to explain biological behavior.

CONCLUSIONS

Hürthle cell neoplasms can now be classified using histopathological as well as molecular criteria. It appears that the new subclassification of malignant HCTs into follicular (HCC) and papillary (HCPTC) variants identifies 2 distinct biological groups.

Renal epithelial neoplasms: the diagnostic implications of electron microscopic study in 55 cases

Several unsettled histogenetic, nosologic and diagnostic considerations for renal epithelial tumors may have ultrastructural ramifications. Yet, a comprehensive electron microscopic study of renal epithelial neoplasms, in light of the recent classification, is not available. The ultrastructural findings from fifty-five renal epithelial neoplasms [31 clear cell renal cell carcinomas (RCC), 11 papillary RCC, 5 chromophobe RCC, 3 sarcomatoid RCC and 5 oncocytomas] were correlated with their light microscopic appearance. Clear cell RCC showed long microvilli similar to the brush border of the normal proximal tubules, with abundant cytoplasmic lipid and glycogen. Papillary RCC showed variably sized microvilli, and small amounts of cytoplasmic lipid, but no glycogen. Chromophobe RCC showed many cytoplasmic vesicles and abnormal mitochondria, with rare short and stubby microvilli. Renal oncocytoma showed many mitochondria with a few vesicles in the apical portion of the cytoplasm and rare short and stubby microvilli. The eosinophilic cell variants of clear cell RCC, papillary RCC and chromophobe RCC showed ultrastructural features similar to those of their respective prototypes, except for an increased numbers of mitochondria in the cytoplasm. One sarcomatoid clear cell RCC showed skeletal muscle differentiation. Two types of cytoplasmic inclusions, i.e. hyaline globules and granules similar to those in the Paneth cells (PC-like granules) were identified only in clear cell RCC, which displayed distinctive ultrastructural features. The current EM study demonstrates distinctive ultrastructural features of renal epithelial neoplasms. The findings lend additional support to the current classification of the pertinent tumor types, facilitate the differential diagnoses, and provide insights into the possible histogenesis of renal epithelial neoplasms.

[Renal onococytic adenoma]

Renal oncocytic adenoma. Renal oncocytic adenoma is a rare neoplasm now considered as a benign tumour. The purpose of this paper is to describe the radiological features of this tumour and to assess the value of imaging work-up in the diagnosis and management of patients with renal oncocytic adenomas.

Contemporary approach to the classification of renal epithelial tumors

Our understanding of the morphologic and genetic features of renal epithelial neoplasia has brought about profound changes in the classification of these tumors. It is clear that they represent a heterogeneous group of tumors with distinct histopathologic, genetic, and clinical features ranging from benign to high-grade malignant. "Granular" and "sarcomatoid" carcinomas are not distinct entities, since tumors with granular or spindle cell features may be seen in many tumor-types. Using conventional pathologic tools such as hematoxylin and eosin staining, histochemistry, immunohistochemistry, and electron microscopy, we are able to properly classify the majority of these tumors. Nevertheless, approximately 6% to 7% of cases are impossible to classify in this fashion, thus requiring molecular genetic studies for proper characterization.

Loss or reduction of Fhit expression in renal neoplasias: correlation with histogenic class

Involvement of the 3p14.2 region of chromosome 3 in kidney cancers was suggested 20 years ago, when a reciprocal constitutional translocation, t(3;8)(p14.2;q24), was shown to segregate with bilateral clear cell renal carcinoma in 3 generations of 1 family. The FHITgene that is interrupted at 3p14.2 by the t(3;8) translocation has been isolated, characterized, and shown to be frequently altered, mainly by internal deletion, in carcinomas or cancer-derived cell lines of the lung, stomach, pancreas, esophagus, cervix, and colon. Although up to 90% of sporadic clear cell renal carcinomas, representing 70% of adult renal carcinomas, exhibit loss of FHIT alleles, FHIT gene alterations have been documented for only a few renal cell carcinoma-derived cell lines. Nevertheless, more than 50% of clear cell carcinomas were recently shown to express little or no Fhit protein, unlike the normal kidney tubule epithelium, which is uniformly strongly positive for Fhit expression. We have extended our immunohistochemical study of expression of Fhit protein to the spectrum of histopathologic subtypes of adult renal tumors. There is an apparent continuum of Fhit expression from the 100% strongly positive oncocytomas through mostly positive papillary and chromophobe to the mostly negative clear cell and sarcomatoid to the negative or predominantly negative collecting duct renal carcinomas. This pattern of diminishing Fhit expression correlates with reported frequency of 3p allele loss in renal carcinomas and may parallel the potential for aggressive behavior of tumors, as suggested by the abundant Fhit expression in the benign oncocytomas and the near absence of Fhit expression in sarcomatoid and collecting duct RCCs.

Neoplasms composed of eosinophilic polygonal cells: an overview with consideration of different cytomorphologic patterns

Neoplasms that are composed of large eosinophilic cells present a distinctive and challenging image to the diagnostic pathologist. Potential lineages for such lesions include several types of epithelial tissue, as well as melanocytic, lymphoid, germ-cell, and mesenchymal proliferations. Attention to morphological details represents a useful first step in the further evaluation of eosinophilic large-cell tumors. These tumors can usually be segregated into one of four cytological categories, including granular eosinophilic (oncocytic and oncocytoid), fibrillary eosinophilic (myoid), globular eosinophilic (rhabdoid and gemistocytic), and diffusely eosinophilic (hyaline-cell and deeply eosinophilic, not further specified). Correlation with anatomic locations, nuances of clinical presentation, and results of electron microscopic and immunohistochemical studies provides additional data that can be used for a specific interpretation, especially if it is applied in an algorithmic fashion.

Quantitative evaluation of apoptosis and proliferation in renal cell carcinoma. Correlation to tumor subtype, cytological grade according to thoenes-classification and the occurrence of metastasis

To analyse growth characteristics of human renal cell tumors, 66 renal cell carcinomas and one oncocytoma were investigated concerning the proliferative activity by immunohistochemical demonstration of the Ki-67 antigen (clone MIB1) and the apoptotic rate using the terminal deoxynucleotidyl-transferase mediated dUTP-fluorescin nick end labelling (TUNEL) method. The TUNEL method indicates DNA double strand breaks considered as a hallmark of programmed cell death (apoptosis). Apoptotic cells were observed in 57 of 67 cases. The apoptotic rate (percentage of stained tumor cells) varied from 0% to 54.1%. GI carcinomas possessed a statistically significant higher apoptotic rate than GII/GIII carcinomas. The proliferation index (percentage of Ki-67 labelled cells) ranged from 0.09% to 22.3%. The well differentiated carcinomas (GI) showed statistically lower proliferative activity than moderate and poorly differentiated carcinomas (GII/GII). The clear cell variant of renal cell carcinoma expressed a higher apoptotic rate than the chromophilic variant. A statistical correlation between apoptosis/proliferation and occurrence of metastasis could not be established. In progression from well to less differentiated renal cell carcinoma the decrease of apoptotic rate, as well as the increase of the proliferative activity, contributes to a rapid tumor growth.

Hürthle cell adenoma of the thyroid: in 32 consecutive cases

Hürthle cell neoplasms of the thyroid gland are uncommon but potentially lethal lesions, the treatment of which is controversial because of a lack of information about their biological and clinical behaviour. Based on histological criteria Hürthle cell tumours cannot always be separated accurately into benign and malignant. Unexpected evolutions with malignant late recurrence of an adenoma previously labelled as benign have been reported. The authors reviewed the clinical and pathological features of 32 patients with Hürthle cell adenomas. The results suggest that total thyroidectomy 'de principe' is not necessary and that some electron microscopy criteria are useful to understand the nature and to predict the biological deportment of Hürthle cell adenomas.

[Thyroidal oxyphilic tumors]

Treatment of thyroidal oxyphilic (Hurthle cell) tumors is controversial due to difficulties in grading tumor malignancy. We classify these tumors into 3 histological subtypes: adenomas, atypical adenomas, and carcinomas. The purpose of this study was to find out whether this classification is a useful criterion for determination of the extent of surgery. Our retrospective study included 5 cases of adenoma, 2 of atypical adenoma and 13 of carcinoma. All histological specimens were revised and were stained immunohistochemically for thyroglobulin. All specimens were positive for thyroglobulin; staining for factor VIII was performed in cases in which the tumor had penetrated into blood vessels. Hemithyroidectomy was used for typical adenomas, while atypical adenomas were treated as carcinomas and total thyroidectomy was performed. 5 patients were treated with radioactive iodine. Taking into account the clinical results, we conclude that histological subtype is a useful guide for proper surgical management. Hemithyroidectomy is proper therapy for adenomas. The management of atypical adenomas was not determined as all were treated as carcinomas.