Mucinous tubular and spindle cell carcinoma of kidney is probably a variant of papillary renal cell carcinoma with spindle cell features

Mucin-secreting clear cell renal cell carcinoma. A rare variant of conventional renal cell carcinoma

We report herein one case of conventional renal cell carcinoma (RCC) producing extensive extracellular mucinous secretion in a 71-year-old man. To the best of our knowledge, the presence of mucinous secretion in this tumor has not been documented. Mucin production, despite its low frequency, can be considered an additional feature of conventional RCC. Therefore, clear cell RCC should be added to the list of parenchymal renal tumors that can show significant mucin secretion; and it should be included in the inventory of morphologic variations of this tumor, which may cause diagnostic difficulties. It is of primary importance to distinguish mucin-secreting clear cell RCC from the metastasis of a mucin-secreting tumor to conventional RCC. Presence of mucin in a clear cell carcinoma does not exclude a renal origin.

Mucinous tubular and spindle cell carcinoma of the kidney: imaging features

This article describes the features on sonography, computed tomography (CT) and magnetic resonance imaging (MRI) of mucinous tubular and spindle cell carcinoma of the kidney. Six pathologically proven cases of mucinous tubular and spindle cell carcinoma of the kidney were identified (5 females, 1 male); all patients underwent preoperative imaging. The mean age of the patients was 58.5 years. Thirteen imaging studies were available for review: 2 sonograms, 1 unenhanced CT scan, 5 contrast-enhanced CT scans, 1 unenhanced magnetic resonance imaging (MRI) examination, and 4 contrast-enhanced MRI examinations. Two abdominal radiologists evaluated all images retrospectively on a PACS workstation using a standardized data collection sheet until consensus was reached. All mucinous tubular and spindle cell carcinomas presented as well-marginated, small (mean 2.6 cm, range 1.9-3.2 cm) predominantly solid masses. No intratumoral fat or calcification was identified. Unenhanced CT and MRI appearances were variable as was the degree of enhancement following intravenous contrast material administration. There was no evidence of perinephric extension, renal vein involvement or metastatic disease in any of the cases. The radiological appearance of mucinous tubular and spindle cell carcinoma is diverse and therefore indistinguishable from the more common subtypes of renal cell carcinoma.

Mucinous tubular and spindle cell carcinoma

A case of a 30-year-old female patient diagnosed with mucinous tubular and spindle cell carcinoma (MT&SCC) of her left kidney of the basis of an abdominal ultrasound scan performed when nonspecific pain is presented. The histopathology report revealed a classic type of MT&SCC. Photographs of histopathological samples are shown. Nephrectomy was applied as sole treatment. A follow-up of six years confirmed surgery to be a sufficient approach. The discussion presents a review of up to date world literature concerning the histopathological features, prognosis, and treatment of MT&SCC.

Clinical genomics of renal epithelial tumors

Kidney and upper urinary tract cancers account for approximately 54,000 cases every year in the United States, and represent about 3.7% of adult malignancies, with more than 13,000 annual deaths. Classification of renal tumors is typically based on histomorphologic characteristics but, on occasion, morphologic characteristics are not sufficient. Each of the most common histologic subtypes harbors specific recurrent genetic abnormalities, such as deletion of 3p in conventional clear cell carcinoma, trisomy 7 and 17 in papillary renal cell carcinoma, multiple monosomies in chromophobe renal cell carcinoma, and a nearly diploid genome in benign oncocytomas. Knowledge of this information can provide diagnostic support and prognostic refinement in renal epithelial tumors. Identification of the specific subtype of a renal tumor is critical in guiding surveillance for recurrence and the appropriate use of targeted therapies. Cytogenomic arrays are increasingly being used as a clinical tool for genome-wide assessment of copy number and loss of heterozygosity in renal tumors. In addition, the improved understanding of the hereditary causes of renal tumors and their role in sporadic malignancies has led to the development of more effective targeted therapies. This review summarizes the genetic and genomic changes in the most common types of renal epithelial tumors and highlights the clinical implications of these aberrations.

Current pathology keys of renal cell carcinoma

CONTEXT

Renal cell carcinoma (RCC) in adults comprises a heterogeneous group of tumours with variable clinical outcomes that range from indolent to overtly malignant. The application of molecular genetic techniques to the study of renal neoplasms has resulted in an improved classification of these entities and a better understanding of the biologic mechanisms responsible for tumour development and progression. The current 2004 World Health Organisation classification of adult renal epithelial neoplasms has expanded rapidly with new categories recently incorporated.

OBJECTIVE

To review and evaluate the evidence implicating pathologic features and classification of RCC in adults as a tool to approach patients' prognosis and modulate current therapy.

EVIDENCE ACQUISITION

Members of Committee 3: Pathology, under the auspices of the International Consultation on Urological Diseases and the European Association of Urology (ICUD-EAU) International Consultation on Kidney Cancer, performed a systematic review using PubMed. Participating pathologists discussed pathologic categories and diagnostic features of RCC in adults.

EVIDENCE SYNTHESIS

We reviewed and discussed articles and the personal experiences of participating uropathologists.

CONCLUSIONS

The conclusions reached by the ICUD-EAU 2010 International Consultation on Kidney Cancer emphasise the appropriate pathologic diagnosis of RCC in adults as a tool to approach patients' prognosis and modulate current therapy. Further emphasis should be placed on defining risk groups of RCC and diagnostic features of unusual tumours such as familial RCC, translocation RCC, and tubular mucinous and spindle cell carcinoma. A number of recently described entities and morphologic variants of classical categories deserves recognition because they can be important in differential diagnosis and therapy.

Immunohistochemical diagnosis of renal neoplasms

CONTEXT

Histologic diagnosis of renal neoplasm is usually straightforward by routine light microscopy. However, immunomarkers may be essential in several contexts, including differentiating renal from nonrenal neoplasms, subtyping of renal cell carcinoma (RCC), and diagnosing rare types of renal neoplasms or metastatic RCC in small biopsy specimens.

OBJECTIVE

To provide a comprehensive review of the diagnostic utility of immunomarkers for renal neoplasms.

DESIGN

This review is based on published literature and personal experience.

CONCLUSIONS

The following markers may have diagnostic utility in various diagnostic contexts: cytokeratins, vimentin, α-methylacyl coenzyme A racemase, carbonic anhydrase IX, PAX2, PAX8, RCC marker, CD10, E-cadherin, kidney-specific cadherin, parvalbumin, claudin-7, claudin-8, S100A1, CD82, CD117, TFE3, thrombomodulin, uroplakin III, p63, and S100P. Cytokeratins are uniformly expressed by RCC, albeit in a somewhat limited amount in some subtypes, requiring broad-spectrum anti-CK antibodies, including both low- and high-molecular-weight cytokeratins. PAX2 and PAX8 are sensitive and relatively specific markers for renal neoplasm, regardless of subtype. CD10 and RCC marker are sensitive to renal cell neoplasms derived from proximal tubules, including clear cell and papillary RCCs. Kidney-specific cadherin, parvalbumin, claudin-7, and claudin-8 are sensitive markers for renal neoplasms from distal portions of the nephron, including chromophobe RCC and oncocytoma. CK7 and α-methylacyl coenzyme A racemase are sensitive markers for papillary RCC; TFE3 expression is essential in confirming the diagnosis of Xp11 translocation RCC. The potentially difficult differential diagnosis between chromophobe RCC and oncocytoma may be facilitated by S100A1 and CD82. Thrombomodulin, uroplakin III, p63, and S100P are useful markers for urothelial carcinoma. Together with high-molecular-weight cytokeratins, PAX2, and PAX8, they can help differentiate renal pelvic urothelial carcinoma from collecting duct RCC. A sensitive marker for sarcomatoid RCC is still not available. Immunomarkers are most often used for diagnosing metastatic RCC. Compared with primary RCC, expression of the above-mentioned markers is often less frequent and less diffuse in the metastatic setting. Recognizing the variable sensitivity and specificity of these markers, it is important to include at least CD10, RCC marker, PAX2, and PAX8 in the diagnostic panel.

Acquired cystic disease-associated renal cell carcinoma with sarcomatoid change and rhabdoid features

Acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) is a recently described entity. To the best of our knowledge, there are no reports of ACD-associated RCC with sarcomatoid and rhabdoid changes. In this article, we present the first case of such a tumor. A 56-year-old Japanese man has received long-term hemodialysis and had a history of right renal cancer. Following the discovery of metastatic cancer in the thoracic wall, detailed imaging studies revealed a mass in the left kidney. The histologic examination of the left renal tumor showed ACD-associated RCC with sarcomatoid change and rhabdoid features. Immunohistochemically, intracytoplasmic globular inclusions in rhabdoid cells were positive for vimentin and cytokeratin CAM5.2. The G-band karyotype showed the following changes: 46, X, +X. -Y[1]/43, idem, add(2)(q31), -6, -9, -14, -15, +16, -22, +mar1[6]/46, XY[2]/abnormal cell[11]. In conclusion, pathologists and urologists should be aware that rhabdoid features may occur in ACD-associated RCC and that the loss of chromosomes 9 and 14 may occur during the process of sarcomatoid change in ACD-associated RCC.

Fine needle aspiration biopsy of renal mucinous tubular and spindle cell carcinoma: report of two cases

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare renal tumor. Here we report two cases of MTSCC which were initially evaluated by fine needle aspiration biopsy (FNAB) and followed by surgical resection of the tumors. The cytomorphologic features of MTSCC were characterized by aggregates of relatively uniform, predominantly oval to spindle cells intermixed with abundant metachromatic myxoid matrix. Only rare epithelioid tumor cells with vacuolated cytoplasm were present. Immunohistochemically, the tumor cells were positive for CK7, CK19, CD10, vimentin, E-cadherin, alpha-methyl CoA racemase, and negative for CK903 and CK20. EMA and carbonic anhydrase IX immunoreactivity was seen in one of the two cases. Multiple chromosomal losses involving chromosomes 1, 2, 17 and likely chromosome 7 were revealed by fluorescence in situ hybridization (FISH). These cytomorphologic, immunophenotypic, and cytogenetic features were helpful for including this entity in the differential diagnosis of renal cell carcinomas.

Uncommon and recently described renal carcinomas

Major consensus conferences held over a decade ago laid the foundations for the current (2004) WHO classification of renal carcinoma. Clear cell, papillary and chromophobe carcinomas account for 85-90% carcinomas seen in routine practice. The remaining 10-15% of carcinomas consist of rare sporadic and hereditary tumors, some of which had been long recognized, but many of which only emerged as distinct entities in the decade leading up to the WHO publication. Collecting-duct carcinoma is a rare, often lethal form of carcinoma. Medullary carcinoma associated with sickle cell trait, has emerged as a distinctive tumor showing some overlapping features with upper tract urothelial carcinoma. Mucinous tubular and spindle-cell carcinoma and tubulocystic carcinoma were earlier considered as patterns of low-grade collecting-duct carcinoma, but are now recognized as separate tumor entities. Carcinomas associated with somatic translocations of TFE3 and TFEB comprise a significant proportion of pediatric renal carcinomas. Oncocytoid renal carcinomas in neuroblastoma survivors was recognized as a unique tumor category in the WHO classification. Renal carcinoma associated with end-stage renal disease is now recognized as having distinct morphological patterns and behavior. In addition there is a group of rare recently described carcinomas, including clear cell papillary carcinoma, oncocytic papillary renal cell carcinoma, follicular renal carcinoma and leiomyomatous renal cell carcinoma. It behooves the surgical pathologist to not only be capable of diagnosing the common forms of renal cancer, but also to be aware of the rare types of renal carcinoma, many of which have emerged in recent years.

Molecular Pathology of the Genitourinary Tract: Molecular Pathology of Kidney and Testes

With the advent of newer molecular technologies, our knowledge of cellular mechanisms with tumors of the kidney and testis has grown exponentially. Molecular technologies have led to better understanding of interplay between the von Hippel-Lindau gene and angiogenic cytokines in renal cancer and isochromosome 12p in testicular neoplasms. The result has been development of antiangiogenic-targeted therapy within recent years that has become the mainstay treatment for metastatic renal cell cancer. In the near future, classification and diagnosis of renal and testicular tumors through morphologic analysis will be supplemented by molecular information correlating to prognosis and targeted therapy. This article outlines tumor molecular pathology of the kidney and testis encompassing current genomic, epigenomic, and proteonomic findings.

Pathologic Features of Adult Renal Cortical Tumors

In the past few years, a much better understanding of the morphologic spectrum of renal cortical tumors has resulted in a clinically highly relevant contemporary classification system of these tumors. The current and still evolving era of targeted therapies in kidney cancer further highlights the importance of the appropriate pathologic classification. The recently gained knowledge about molecular-driven antigen expression almost certainly will have a major role to play in the characterization, development, and evaluation of targeted therapies in kidney cancer in the future.

[Papillary renal cell carcinoma spectrum]

OBJECTIVES

Significant conceptual expansion of renal cancer continues to increase. The key point to this phenomenon is based on the combination of morphology and molecular data. The result is the new 2004 WHO classification of renal tumors in adults. The apparently never ending advance in molecular genetics is constantly pushing to update recently proposed listings.

MATERIAL AND METHODS

Papillary renal cell carcinoma, considered the term in the broader sense, is the subject of this study. This histological phenotype in renal cancer, with an accelerated growth in the last times, is a good example of the never ending evolution of pathology as a clinical discipline.

RESULTS

The genetic background and the phenotype of all renal neoplasms with papillary or tubulo-papillary phenotype, or with its genetic background, some of them being very recently described entities even now under discussion is wide and heterogenous: conventional sporadic papillary carcinoma, papillary carcinomas linked to genetic syndromes (hereditary papillary carcinoma, papillary carcinoma associated to hereditary leiomyomatosis, papillary carcinoma associated to hereditary papillary thyroid carcinoma, Birt-Hogg-Dubé syndrome) or to specific genetic disorders (Xp11.2 associated papillary carcinoma), papillary carcinoma with distinct morphology (micropapillary carcinoma, inverted papillary carcinoma, papillary carcinoma with spindle cells and angulated tubules) and new renal carcinomas included within the group of papillary carcinoma (tubulo-cystic carcinoma and tubular, mucinous and spindle cell carcinoma).

CONCLUSION

Aside from the classically known histological variants, several new entities, some of them still badly delineated, are progressively enlarging the group of renal carcinomas with papillary phenotype. This growth will continue in the next times on the light of the new findings and pathologists will be main actors in this fact.

[An unusual renal neoplasm: mucinous tubular and spindle cell carcinoma]

Mucinous tubular and spindle cell carcinoma is a rare and newly described type of renal cell carcinoma (RCC) with a relatively indolent behaviour. We report a case of 53-year-old woman who had macroscopic hematuria and flank pain. A right radical nephrectomy was performed showing a well circumscribed tumour confined to the kidney and measuring 17cm. The histologic findings consisted of tightly packed, small, elongated tubules separated by pale mucinous stroma. The tumour cells were cuboidal to spindled with eosinophilic cytoplasm and lower nuclear grade. Tumour was immunoreactive for cytokeratin CK 7, CK19 and epithelial membrane antigen (EMA). The morphological and immunohistochemical features were consistent with mucinous tubular and spindle cell carcinoma of kidney.

Mucinous tubular and spindle cell carcinoma with aggressive histomorphology--a sarcomatoid variant

Mucinous tubular and spindle cell carcinoma (MTSCC) is a recently described renal epithelial tumor. The bland cytomorphology of the spindled component and low-grade behavior help in its differentiation from sarcomatoid renal carcinoma. Sarcomatoid change has been reported in most histologic variants of renal cell carcinoma apart from MTSCC. Herein we report a case of an MTSCC in a 72-year-old female patient with high-grade spindled areas resembling fibrosarcomatous and undifferentiated pleomorphic sarcoma patterns with metaplastic bone. This index case also demonstrates a high proliferation index and extensive necrosis representing the first documented case of sarcomatoid change in MTSCC.

Tubulocystic carcinoma of the kidney: clinicopathologic and molecular characterization

The nature of tubulocystic carcinoma, a rare renal tumor composed of tubular and cystic structures, is poorly understood. It has been suggested that it may represent a low-grade collecting duct carcinoma of the kidney despite the lack of sufficient molecular and pathologic evidence. The aim of this study was to examine the clinical and pathologic features of 13 cases of tubulocystic carcinoma of the kidney. Furthermore, using gene expression microarray analysis, we defined the molecular signature of this tumor by comparing it with other renal tumors in our previously established molecular profile database. Histologically, all 13 tumors were composed of closely packed tubules and cysts of varying sizes separated by fibrovascular septa. The epithelial lining cells of the tubules and cysts in this tumor were characterized by abundant eosinophilic cytoplasm with prominent nucleoli often showing a hobnail appearance. Clinically, one of the 13 cases showed metastasis to the pelvic lymph nodes. Five of the 13 cases coexisted with papillary renal cell carcinoma (RCC) (n=3) or papillary adenoma (n=2). In addition, the molecular profile of tubulocystic carcinoma was similar but not identical to those of papillary RCC by clustering analysis. Through comparative genomic microarray analysis, tubulocystic carcinoma showed gains of chromosome 17, but not chromosome 7, whereas most papillary RCCs showed chromosomal gains in both 7 and 17 (trisomies). Therefore, based on its unique pathologic features and molecular signature as well as its biologic behavior to develop metastasis either by itself or in association with papillary RCC, tubulocystic carcinoma of the kidney should be recognized as a distinct subtype of RCC and be distinguished from other malignant and benign cystic lesions of the kidney.