Mucinous tubular and spindle cell carcinoma: a report of 15 cases and a review of the literature

Indolent mucinous tubular and spindle cell carcinoma of the kidney: A case report and review of the literature

Mucinous tubular and spindle cell carcinoma of the kidney (MTSCC) is a rare subtype of renal cancer. It consists of tubules separated by mucus stroma and a spindle cell. Few cases have been reported; thus, the imaging features of MTSCC are not well characterized. An MTSCC in the left kidney of a 65-year-old woman was incidentally discovered during a medical checkup. A review of the patient's medical history revealed that this kidney lump had an indolent growth process. The current study presented this case and reviewed the pathological features, imaging findings and treatment options of MTSCC to strengthen the recognition of this rare renal neoplasm by radiologists.

A contemporary guide to chromosomal copy number profiling in the diagnosis of renal cell carcinoma

The routine clinical implementation of molecular methods other than fluorescence in situ hybridization in the evaluation of renal neoplasia is currently limited, as the current standard of care primarily involves a combination of morphologic and immunophenotypic analysis of such tumors. Amongst various molecular techniques, global copy number profiling using single nucleotide polymorphism-based microarrays, colloquially referred to as SNP-arrays, is being increasingly utilized to profile renal tumors, as several subtypes have characteristic recurrent patterns of copy number alterations. Recurrent copy number alterations in common tumor types include loss of chromosome 3p in clear cell renal cell carcinoma (RCC), gain of chromosomes 7 and 17 in papillary RCC and multiple losses in chromosomes 1, 2, 6, 10, 13, 17, and 21 in chromophobe RCC. Such assays are being increasingly utilized in the clinical setting. Herein, we discuss some common clinical applications of such testing that includes high yield diagnostic and prognostic applications. Diagnostic utility includes evaluation of tumor types that are primarily defined by underlying copy number alterations, establishing the underlying subtype in high grade dedifferentiated (unclassified) renal tumors, as well as assessment of loss of heterozygosity, which is an important component in the workup for germline alterations in tumor suppressor genes. Universal adoption of these techniques across clinical laboratories will likely be significantly affected by variables such as cost, reimbursement, and turnaround time.

Mucinous Tubular and Spindle Cell Carcinoma of the Kidney: A Study of Clinical, Imaging Features and Treatment Outcomes

Purpose

To describe the clinical, imaging, pathological features and oncologic outcomes of mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney.

Patients and Methods

Twenty-two cases of MTSCC were pathologically identified between January 2004 and April 2021 at our institution. The clinical and imaging findings, pathological features, treatment methods and outcomes of the patients were reviewed.

Results

These cases included 17 women and 5 men, with a median age at diagnosis of 52.5 years. On contrast-enhanced CT, MTSCC was less enhanced than the adjacent renal parenchyma. Tumor attenuation values were 33.3 ± 6.8HU, 44.0 ± 9.1HU, 54.4 ± 13.9HU and 67.1 ± 11.8HU in the non-contrast, corticomedullary, nephrographic and excretory phases of CT, respectively. Contrast-enhanced ultrasonography and MRI also showed hypovascular features of the masses. On MRI, the tumors were isointense on T1-weighted images and slightly hypo- or hyperintense on T2-weighted images. Diffusion-weighted imaging revealed a low apparent diffusion coefficient of the tumor. The patients were managed with laparoscopic partial nephrectomy (n=5), radical nephrectomy (n=16), or robotic-assisted laparoscopic partial nephrectomy (n=1). The median follow-up time was 59.5 months. All the patients were free of local recurrence or distant metastasis.

Conclusions

MTSCC is generally indolent and has favorable outcomes. The imaging features of MTSCC are generally hypovascular, which is significantly different from clear cell renal cell carcinoma. However, it is still difficult to distinguish MTSCC from other hypovascular renal tumors preoperatively because their imaging features overlap. Further studies are essential to fully characterize the features of this rare RCC variant.

Mucinous tubular and spindle cell carcinoma with high-grade transformation: case report

Background

Mucinous tubular and spindle cell carcinoma (MTSCC) is a type of renal cell carcinoma (RCC) described as an entity with low-grade and low malignant potential. This report presents a high-grade transformation of MTSCC which is an uncommon finding in this subtype of RCC. Although most reported cases showed low malignant potential and good prognosis after surgical resection, a small subset of patients has been reported with aggressive phenotype and fatal outcome.

Case presentation

A case of a 23-year-old male is discussed with an incidental renal mass in the left kidney after a workup of bilateral flank pain. Morphologically, the tumor was composed of tubular structures lined by cuboidal cells mixed with spindle cells and sarcomatoid change was present in the tumor. Previously sarcomatoid change has been mostly reported along with conventional morphology in other common type of RCC with a worse prognosis.

Conclusions

The aim of this report is to draw the attention of pathologists and clinicians to the importance of high grade MTSCC owing to the unfavorable prognosis.

Proteomic profiling identifies novel diagnostic biomarkers and molecular subtypes for mucinous tubular and spindle cell carcinoma of the kidney

Mucinous tubular and spindle cell carcinoma (MTSCC) is a relatively rare renal epithelial neoplasm resembling type 1 papillary renal cell carcinoma (PRCC) morphologically and immunohistochemically. The accurate diagnosis of MTSCC remains a challenge. Here, by using proteomic profiling, we characterized MTSCC and PRCC to identify diagnostic biomarkers. We found that the MTSCC tumor proteome was significantly enriched in B‐cell‐mediated immunity when compared with the proteome of adjacent normal tissues of MTSCC or tumors of PRCC. Importantly, we identified MZB1, VCAN, and SOSTDC1 as diagnostic biomarkers to distinguish MTSCC from the solid variant of type 1 PRCC, with an AUC of 0.985 when combined. MZB1 was inversely correlated with tumor clinical stage and may play an anti‐tumor role by activating the complement system. Finally, unsupervised clustering revealed two molecular subtypes of MTSCC, displaying different morphology, expression signatures of oxidative phosphorylation, and aggravation. In summary, our analyses identified a three‐protein diagnostic panel and molecular subtypes for MTSCC. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Key Renal Neoplasms With a Female Predominance

Renal neoplasms largely favor male patients; however, there is a growing list of tumors that are more frequently diagnosed in females. These tumors include metanephric adenoma, mixed epithelial and stromal tumor, juxtaglomerular cell tumor, mucinous tubular and spindle cell carcinoma, Xp11.2 (TFE3) translocation-associated renal cell carcinoma, and tuberous sclerosis complex (somatic or germline) associated renal neoplasms. The latter category is a heterogenous group with entities still being delineated. Eosinophilic solid and cystic renal cell carcinoma is the best-described entity, whereas, eosinophilic vacuolated tumor is a proposed entity, and the remaining tumors are currently grouped together under the umbrella of tuberous sclerosis complex/mammalian target of rapamycin-related renal neoplasms. The entities described in this review are often diagnostic considerations when evaluating renal mass tissue on biopsy or resection. For example, Xp11.2 translocation renal cell carcinoma is in the differential when a tumor has clear cell cytology and papillary architecture and occurs in a young or middle-aged patient. In contrast, tuberous sclerosis complex-related neoplasms often enter the differential for tumors with eosinophilic cytology. This review provides an overview of the clinical, gross, microscopic, immunohistochemical, genetic, and molecular alterations in key renal neoplasms occurring more commonly in females; differential diagnoses are also discussed regardless of sex predilection.

Mucinous Tubular and Spindle Cell Carcinoma of the Kidney with Nodal Metastasis Managed with Surgical Resection

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare renal malignancy that usually follows an indolent course. The few existing reports of metastatic MTSCC show poor response to systemic therapy. Here we describe the unusual case of a 39-yr-old male with MTSCC presenting as a large renal mass with bulky retroperitoneal lymphadenopathy managed with complete resection of disease. He has remained free of recurrence for 1 yr postoperatively. On the basis of the experience reported here, aggressive surgical resection of MTSCC with isolated nodal metastases may be considered for similar patients in the future given the historically poor response rates to systemic therapy.

Mucinous tubular and spindle cell carcinoma of the kidney: A case series with a brief review of the literature

Background

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare low grade renal tumour exhibiting characteristic morphological features. We share our experience and discuss briefly, a review of the current literature.

Methods

Electronic medical records were searched between January 2005 to January 2017. The histopathology and immunohistochemistry slides were retrieved and reviewed.

Results

Eleven cases of MTSCC were identified. Mean age at presentation was 53.9 (age range 41 to 71) years with a slight female preponderance (F: M=6:5). Clinical stage at presentation was: Stage I (4 cases), Stage II (3 cases), Stage III (1 case), and Stage IV (3 cases). The average tumour size was 7.5cm (range 3.5 to 17cm). Microscopically, characteristic biphasic tumour with tubular and spindle cell morphology with variable mucinous stroma was noted in all. The prominent immunohistochemical profile revealed positivity for CK7 (7/8, 87.5%), AMACR (6/8, 75%), AE1/3 (4/4, 100%), CD10 (3/10, 27.3%), and Vimentin (3/3, 100%). Seven patients (Stage I and II) had been treated with nephrectomy, whereas only a diagnostic biopsy was available in four patients who presented with locally advanced disease (n=1) or distant metastasis (n=3) at presentation. The mean follow-up was 37.8 months (range 8 to 96 months), available in 10 out of 11 patients, without recurrence in nine while one died 8 months after diagnosis.

Conclusion

MTSCC is an indolent renal cancer with characteristic morphology. However, presentation with locally advanced disease or distant metastasis may be seen in a subset of these patients. This warrants close follow-up in even localized tumors.

Mucinous tubular and spindle cell carcinoma of the kidney: Five case reports and review of the literature

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a rare and polymorphic tumor, which has been previously considered to be a low-grade malignancy, predominantly occurring in women. To the best of our knowledge, MTSCC with bladder metastasis has never been reported. The current study presents five adult cases of MTSCC that included three male and two female patients. Among the male cases, two were of advanced stage, one with MTSCC and renal chromophobe cell carcinoma with bladder metastasis and the other with MTSCC with invasion of the renal vein. The other three cases with small masses were at an early stage. All five cases had a good prognosis and were without recurrence after several years of follow-up. A 70-year-old male with intermittent gross hematuria, intermittent renal colic, and groin radiation pain for a year (case 1), was incidentally detected to have a left renal density mass by total abdominal enhanced computed tomography scans. In the other four cases, renal masses were found by B-ultrasound. The patient in case 1 underwent a retroperitoneal laparoscopic radical nephroureterectomy with bladder cuff resection and transurethral resection of the bladder tumor, and received gemcitabine hydrochloride via intravesical instillation therapy plus cisplatin chemotherapy every 3 months. The patient in case 2 underwent an open left radical nephrectomy and renal pedicle lymph node dissection. The other three patients underwent a laparoscopic radical nephrectomy. All five patients had no recurrence or new metastasis in other organs after follow-up. In conclusion, the incidence of MTSCC in men and women is not as disparate as reported in previous publications. The characteristics of the images of the five adult cases in the present study showed a considerable consistency, with only minor differences. The malignancy and prognosis of MTSCC are still controversial, and thus inclusion and review of more cases is required to reach a definite final conclusion. Sunitinib and gemcitabine chemotherapy in combination with cisplatin may be effective for the therapy of MTSCC patients with metastasis, but a larger range of treatments needs to be identified.

Renal Cell Tumors: Molecular Findings Reshaping Clinico-pathological Practice

Over the past 20 years, the number of subtypes of renal epithelial cell neoplasia has grown. This growth has resulted from detailed histological and immunohistochemical characterization of these tumors and their correlation with clinical outcomes. Distinctive molecular phenotypes have validated the unique nature of many of these tumors. This growth of unique renal neoplasms has continued after the 2016 World Health Organization (WHO) Classification of Tumours. A consequence is that both the pathologists who diagnose the tumors and the clinicians who care for these patients are confronted with a bewildering array of renal cell carcinoma variants. Many of these variants have important clinical features, i.e. familial or syndromic associations, genomics alterations that can be targeted with systemic therapy, and benignancy of tumors previously classified as carcinomas. Our goal in the review is to provide a practical guide to help recognize these variants, based on small and distinct sets of histological features and limited numbers of immunohistochemical stains, supplemented, as necessary, with molecular features.

Distinct Genomic Copy Number Alterations Distinguish Mucinous Tubular and Spindle Cell Carcinoma of the Kidney From Papillary Renal Cell Carcinoma With Overlapping Histologic Features

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a rare type of renal cell carcinoma that frequently exhibits histologic and immunophenotypic features overlapping with type 1 papillary renal cell carcinoma (PRCC). To clarify molecular attributes that can be used for this difficult differential diagnosis, we sought to delineate the genome-wide copy number alterations in tumors displaying classic histologic features of MTSCC in comparison to the solid variant of type 1 PRCC and indeterminate cases with overlapping histologic features. The study included 11 histologically typical MTSCC, 9 tumors with overlapping features between MTSCC and PRCC, and 6 cases of solid variant of type 1 PRCC. DNA samples extracted from macrodissected or microdissected tumor areas were analyzed for genome-wide copy number alterations using an SNP-array platform suitable for clinical archival material. All cases in the MTSCC group exhibited multiple chromosomal losses, most frequently involving chromosomes 1, 4, 6, 8, 9, 13, 14, 15, and 22, while lacking trisomy 7 or 17. In contrast, cases with overlapping morphologic features of MTSCC and PRCC predominantly showed multiple chromosomal gains, most frequently involving chromosomes 7, 16, 17, and 20, similar to the chromosomal alteration pattern that was seen in the solid variant of type 1 PRCC cases. Morphologic comparison of these molecularly characterized tumors identified histologic features that help to distinguish MTSCC from PRCC, but immunohistochemical profiles of these tumors remained overlapping, including a marker for Hippo-Yes-associated protein signaling. Characteristic patterns of genome-wide copy number alterations strongly support MTSCC and PRCC as distinct entities despite their immunohistochemical and certain morphologic overlap, and help define histologic features useful for the classification of questionable cases.

Mucinous Tubular and Spindle-Cell Carcinoma of the Kidney: Clinical Features, Genomic Profiles, and Treatment Outcomes

BACKGROUND

Mucinous tubular and spindle-cell carcinoma (MTSCC) is a rare kidney cancer subtype with limited cases reported in the literature. We report on outcomes of 25 patients with this variant who were managed at our institution.

MATERIALS AND METHODS

The institution database was queried, and clinical data extracted for patients with MTSCC. Molecular features examined included next-generation sequencing with Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets and allele-specific copy number analysis using the Fraction and Allele-Specific Copy Number Estimates from Tumor Sequencing (FACETS) algorithm in a subset of patients.

RESULTS

All patients underwent primary tumor-directed therapy (nephrectomy = 23, cryoablation = 2). Metastases were diagnosed in 6 patients (24%), 3 (12%) of whom had de novo metastatic disease. Five of 6 patients with metastatic disease had high-grade histological features compared with 0 of 19 nonmetastatic patients (83% vs. 0%; P < .001, Fisher exact test). Three-year overall survival from diagnosis was 84.8% (95% confidence interval, 59.6-94.9) with a median follow-up time of 3.9 years (range, 1 month to 10.3 years). Three deaths occurred, all from metastatic disease. Four patients received systemic therapy with time to treatment failure ≤6 months across different agents with the exception of 1 patient with prolonged response with sunitinib treatment (30.6 months). The most frequent molecular alterations were neurofibromin 2 mutations (n = 2; 40%), germline alterations (n = 2; 40%) including checkpoint kinase 2 and BRCA2 DNA repair associated mutations, multiple chromosomal copy number losses, and mismatch repair deficiency in 1 patient.

CONCLUSION

MTSCC is characterized by localized tumors treated successfully with primary tumor-directed therapy. However, patients with high-grade histological features were more likely to develop metastatic disease with limited responses to standard therapies.

Mucinous Tubular and Spindle Cell Carcinoma: A Review of Histopathology and Clinical and Prognostic Implications

Mucinous tubular and spindle cell carcinomas are rare kidney tumors with generally indolent behavior. As the name suggests, classic histomorphology reveals bland spindle cells, tubules, and mucinous stroma. Uncommon histologic features include mucin-poor stroma, high nuclear grade, cellular pleomorphism, and presence of necrosis. Rare cases can show aggressive growth and distant metastasis. Mucinous tubular and spindle cell carcinoma has characteristic chromosomal abnormalities and the molecular signature remains the same, irrespective of the varied histomorphology.

Imaging features of primary renal lymphoma

Background Cases of primary renal lymphoma (PRL) are quite rare and are often mistaken for renal cell carcinoma. Purpose To determine the multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) characteristics of PRL. Materials and Methods Twenty-three patients with PRL were identified by CT and MRI, and their tumor characteristics were assessed. Results Tumors exhibited single or multifocal nodules (n = 19) and diffuse renal enlargement (n = 4). Twenty-two tumors exhibited an infiltrative appearance. There was no evidence of calcification in any of the cases. Twenty-one tumors displaced or wrapped around abdominal vessels rather than encasing them. Enlarged retroperitoneal nodes were observed in three cases. Neither extension into the venous system nor distant metastasis was found. Tumor enhancement was of low attenuation compared with that of normal renal cortex and medulla ( P < 0.05). PRL was isointense on T1-weighted imaging, slightly hypointense on T2-weighted imaging and hyperintense on diffusion-weighted imaging. Twenty-two patients exhibited biopsy-confirmed PRN. There were four, 12, and seven cases of low-grade, intermediate-grade, and high-grade tumors, respectively. Patient were followed up over 16 to 166 months. Six patients died within three years and five patients died within five years. Conclusion Infiltrative appearance and tumor displacement or extension around abdominal vessels rather than vessel encasement are common findings on CT or MRI imaging and may suggest a diagnosis of PRL.

Mucin-poor and aggressive mucinous tubular and spindle cell carcinoma of the kidney: Two case reports

Mucinous tubular and spindle cell carcinoma (MTSCC) is a relatively rare renal epithelial neoplasm. Although MTSCC is considered to be a low-grade and indolent neoplasm, aggressive cases have been recently reported. The present study discussed two additional cases of high-grade MTSCC causing multiple distant metastases with a fatal course. In case 1, a 71-year-old patient presented with hematuria and pyuria. Computed tomography (CT) scan of the right kidney revealed a mass lesion, for which partial nephrectomy was performed. However, a follow-up CT imaging revealed distant metastases in the liver, the paraaortic lymph nodes and the bone. Despite molecular targeted therapy and irradiation, the patient succumbed due to tumor progression. In case 2, a 64-year-old patient presented with an incidentally identified mass lesion in the right kidney. A laparoscopic nephrectomy was performed, and a follow-up CT imaging revealed metastases in the skin and lungs. The cytology of pleural effusion revealed pleuritis carcinomatosa. Histologically, both cases were diagnosed as mucin-poor MTSCC with high-grade transformation, which comprised uniform tumor cells primarily forming slender tubules. The tumors contained low- and high-grade regions. In addition, venous invasion and necrosis were observed. The tumor cells also demonstrated increased Ki-67 labeling indices and cellular tumor antigen p53 (p53) nuclear accumulation. High-grade transformation, large tumor size, necrosis, venous invasion, high Ki-67 labeling index and p53 nuclear accumulation are generally predictive findings for aggressive behavior of malignant tumors. In the current report, it was emphasized that MTSCC possesses a wide spectrum of clinicopathological features. Thus, careful postoperative investigation is required for MTSCC with high-grade elements due to its aggressive nature.

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.

Unusual Case of Coexisting Renal Malignancies: Mucinous Tubular and Spindle Cell Carcinoma Kidney With Sarcomatoid Dedifferentiation

Mucinous tubular and spindle cell carcinoma (MTSCC) is a recent entity introduced in the World Health Organization 2004 Classification. It is a tumour of low malignant potential. MTSCC is a subtype of renal cell carcinoma (RCC), which is characterized by a polymorphous histology, wherein the spindled epithelial cell is an inherent carcinomatous component. We report the case of a 57-year-old man presenting with loin pain and dragging sensation. Imaging revealed a large mass arising from the left kidney. Radical nephrectomy was performed, and histopathology revealed spindle cell elements of MTSCC with low-grade cytology, which occasionally blended with tubular structures in variable mucinous stroma admixed with spindle sarcomatoid cells with marked nuclear pleomorphism, associated with significant necrosis and mitoses of up to 5/10 high-power field. A final diagnosis of MTSCC along with high-grade areas consistent with sarcomatoid dedifferentiation was made. Sarcomatoid dedifferentiation has been well documented in various subtypes of RCC, and its presence signifies a worse prognosis in RCC.

Mucinous tubular and spindle cell renal cell carcinoma: a review of clinicopathologic aspects

Mucinous tubular and spindle cell renal cell carcinoma is a rare, recently described variant of renal cell carcinoma characterized by an admixture of cuboidal cells in tubules and sheets of spindle cells, and variable amounts of mucinous stroma. It has been recognized as a distinct entity in the 2004 World Health Organization tumor classification. Since then, several dozen of these tumor have been reported with additional complementary morphologic characteristics, immunohistochemical profile, and molecular genetic features that have further clarified its clinicopathologic aspects. Although originally considered as a low grade renal cell carcinoma on the basis of its bland appearing nuclear features and indolent clinical course, mucinous tubular and spindle cell renal cell carcinoma has currently been proven to be a tumor that has a histological spectrum ranging from low to high grade that includes sarcomatoid differentiation. In this review, we present a detailed summary of the current knowledge regarding the clinicopathologic, immunohistochemical, molecular genetic, and prognostic characteristics, as well as differential diagnoses of mucinous tubular and spindle cell renal cell carcinoma.

Mucinous spindle and tubular renal cell carcinoma: analysis of chromosomal aberration pattern of low-grade, high-grade, and overlapping morphologic variant with papillary renal cell carcinoma

The chromosomal numerical aberration pattern in mucinous tubular and spindle renal cell carcinoma (MTSRCC) is referred to as variable with frequent gains and losses. The objectives of this study are to map the spectrum of chromosomal aberrations (extent and location) in a large cohort of the cases and relate these findings to the morphologic variants of MTSRCC. Fifty-four MTSRCCs with uniform morphologic pattern were selected (of 133 MTSRCCs available in our registry) and divided into 3 groups: classic low-grade MTSRCC (Fuhrman nucleolar International Society of Urological Pathology grade 2), high-grade MTSRCC (grade 3), and overlapping MTSRCC with papillary renal cell carcinoma (RCC) morphology. Array comparative genomic hybridization analysis was applied to 16 cases in which DNA was well preserved. Four analyzable classic low-grade MTSRCCs showed multiple losses affecting chromosomes 1, 4, 8, 9, 14, 15, and 22. No chromosomal gains were found. Four analyzable cases of MTSRCC showing overlapping morphology with PRCC displayed a more variable pattern including normal chromosomal status; losses of chromosomes 1, 6, 8, 9, 14, 15, and 22; and gains of 3, 7, 16, and 17. The group of 4 high-grade MTSRCCs exhibited a more uniform chromosomal aberration pattern with losses of chromosomes 1, 4, 6, 8, 9, 13, 14, 15, and 22 and without any gains detected. (1) MTSRCC, both low-grade and high-grade, shows chromosomal losses (including 1, 4, 6, 8, 9, 13, 14, 15, and 22) in all analyzable cases; this seems to be the most frequent chromosomal numerical aberration in this type of RCC. (2) Cases with overlapping morphologic features (MTSRCC and PRCC) showed a more variable pattern with multiple losses and gains, including gains of chromosomes 7 and 17 (2 cases). This result is in line with previously published morphologic and immunohistochemical studies that describe the broad morphologic spectrum of MTSRCC, with changes resembling papillary RCC. (3) The diagnosis of MTSRCC in tumors with overlapping morphology (MTSRCC and PRCC) showing gains of both chromosomes 7 and 17 remains questionable. Based on our findings, we recommend that such tumors should not be classified as MTSRCC but rather as PRCC.

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney: a detailed study of radiological, pathological and clinical outcomes

OBJECTIVE

To characterise the clinical, radiological and histological features of mucinous tubular and spindle cell carcinoma (MTSCC), as well as oncological outcomes.

PATIENTS AND METHODS

This is a single institution retrospective analysis of all patients with MTSCC from 2002 to 2011. Patients were excluded if MTSCC could not be confirmed on pathology re-review (four patients). Clinical characteristics, pathology, imaging, and outcomes were reviewed for the 19 included patients.

RESULTS

The median (range) age at diagnosis was 59 (17-71) years with a female predominance (78.9%). On contrast-enhanced computed tomography, MTSCC enhanced less than the cortex during the corticomedullary phase. The mean (range) tumour attenuation was 36 (24-48), 67 (41-133), 89 (49-152), and 76 (52-106) Hounsfield units in the pre-contrast, corticomedullary, nephrographic and excretory phases, respectively. In all, 16 patients were treated with partial (five patients) or radical nephrectomy (11) for pT1 (62.5%), pT2 (31.3%), and pT3a disease (6.3%). One patient underwent active surveillance. Of three patients (13.0%) managed with energy ablation, there was one recurrence that was treated with salvage surgery. One patient (5.3%) had metastatic disease at diagnosis and died from disease 64.7 months later. A patient with a pT2bN0M0 MTSCC with sarcomatoid dedifferentiation developed bone metastases 9.5 months after diagnosis and was alive at 19.0 months. The remainder were free of recurrence or progression.

CONCLUSION

MTSCC is a rare renal cell carcinoma (RCC) variant. In this largest series to date, MTSCC presented at a broad range of ages and displayed a female predilection. Imaging and pathological features of MTSCC display some overlap with papillary RCC. MTSCC is associated with excellent outcomes overall, but is not universally indolent.

Distal nephron neoplasms

Tumours of the distal nephron are uncommon but can create diagnostic difficulties. They may be divided into three groups-tumours of intercalated cell phenotype, those of principal cell phenotype and others with an unconfirmed distal nephron origin. Oncocytomas, chromophobe carcinoma and hybrid oncocytoma chromophobe carcinoma, all show features of intercalated cells and the distinction amongst these is one of the most common areas of diagnostic dilemma. Collecting duct carcinoma and renal medullary carcinoma are the most aggressive forms of renal cancer but recent evidence suggests they may respond to targeted therapy so their recognition becomes crucial to the management of these patients. There remains debate over the precise phenotype of both tubulocystic carcinoma and mucinous tubular and spindle cell carcinoma.

Mucinous tubular and spindle cell carcinoma and solid variant papillary renal cell carcinoma: a clinicopathologic comparative analysis of four cases with similar molecular genetics datum

Mucinous tubular and spindle cell carcinoma (MTSC) was first recognized as a specific entity in the World Health Organization 2004 classification. The “classic” tumor presentation includes an extracellular blue-gray mucinous/myxoid matrix accompanying the typical tubular and spindle cell epithelial components. Tubules are lined by cuboidal to columnar cells with bland nuclei, central small to medium sized nucleoli, and few to no mitoses. By expanding the histologic spectrum, a number of studies highlighted the distinction between MTSC and solid variant of papillary renal cell carcinoma (sPRCC), although controversy still exists. Here, we evaluated two cases of MTSC and compared two cases of sPRCC by light microscopy, special staining, immunohistochemical staining and fluorescence in situ hybridization (FISH). We found that morphologic and immunophenotyping features showed more overlap between MTSC and sPRCC. In addition, gains of chromosomes 7 and 17 and loss of Y, which are characteristic of PRCC, were observed in two cases of sPRCC and one case of MTSC, suggesting that MTSC is similar to sPRCC or may be a subtype of PRCC.

Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_194

Renal mucinous tubular and spindle cell carcinoma: a report of 8 cases and review of the literature

Background

Mucinous tubular and spindle cell carcinoma of kidney (MTSCC-K) is a rare variant of renal tumor. The current data show most of MTSCCs are of low malignant potential and rare cases metastatic to lymph nodes have been reported; however, the recorded computed tomography (CT) and follow up data are limited.

Material and method

In the present study, we retrospectively analyzed CT and clinicopathological data of eight patients with renal MTSCC-K.

Results

A total of eight cases, including six females and two males, were included in this analysis with a mean age of 48.4 (range 25 to 81) years. Mean tumor size was 4.2 (range 2.5 to 10.0) cm. Preoperative CT demonstrated that all tumors were slightly enhanced on both corticomedullary and nephrographic phase, which was different from many other renal cell carcinomas. Three of them were treated with open radical nephrectomy, three with laparoscopic radical nephrectomy and the other two with laparoscopic partial nephrectomy. No postoperative therapy was applied. Patients were followed up for 15 to 64 months and there was no evidence of recurrence and metastasis.

Conclusions

The MTSCC-K has special clinicopathological characteristics, low degree of malignancy and relative good prognosis. The diagnosis mainly depends on the histopathological examination and CT may help to differentiate with papillary renal cell carcinoma. Surgical treatment is recommended and additional therapies are not necessary.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8435581771088249.

Rare (<1%) histological subtypes of renal cell carcinoma: an update

Recent advances in genetics and pathology have allowed description of several new histological subtypes of renal cell carcinoma (RCC) as well as better characterization of other rare subtypes. We herein present a comprehensive review of taxonomy, epidemiology, pathology, imaging findings, and natural history of a wide spectrum of rare subtypes of RCCs that individually constitute <1% of all the RCCs.

Interpretation of needle biopsies of the kidney for investigation of renal masses

The development of new therapeutic options for renal tumors has lead to the need of a pretherapeutic diagnosis for an increasing proportion of patients presenting with a renal mass. This need is particularly important for a small, incidentally discovered renal mass (less than 4 cm) as it can be a benign lesion in a significant percentage of cases. Recent studies have shown that needle biopsy is an accurate and safe method allowing for a precise histopathological diagnosis of the mass in most cases. The aims of the biopsy are (1) to assess the benign or malignant nature of the lesion, (2) to assess the primary or secondary nature of the lesion, and (3), in case of a primary malignancy, to determine histological prognostic factors, such as the tumor type. This review, based on the most recent literature and our own experience, is intended to provide a practical approach to the diagnosis, relying on appropriate morphologic assessment and the use of immunohistochemistry.

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.

Delivering preventive, predictive and personalised cancer medicine for renal cell carcinoma: the challenge of tumour heterogeneity

Recent years have seen major advances in the management of metastatic renal cell carcinoma (mRCC). The tyrosine kinase and mammalian target of rapamycin inhibitors have resulted in disease control and improved survival for many patients with mRCC, but they have not led to preventive, predictive or personalised medicine (PPPM). Failure to achieve this rests ultimately with inadequate knowledge of tissue and molecular heterogeneity; discovery of these drugs was based upon identification of pathogenic molecular pathways in RCC, but research into molecular factors which underpin drug response, resistance and selection of therapy for individual patients has lagged well behind clinical trials of drug development. This review will provide an overview of the development of targeted drug therapies for mRCC, will discuss the challenges which currently impede the delivery of PPPM, including identification of biomarkers, drug resistance and molecular heterogeneity, and will propose research methodologies and technologies required to overcome these obstacles.

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.

Genetic profiles in renal tumors

Renal cell carcinoma in adult comprises a heterogeneous group of tumors with variable clinical outcomes, which ranges from indolent to aggressively malignant. The application of molecular genetics techniques to the study of renal neoplasms has resulted in improved classification of these entities and better understanding of biological mechanisms responsible for tumor development and progression. In the present article we review the molecular genetic profiles of different renal cell tumors and discuss their relevance to the carcinogenesis mechanisms and to the clinical diagnosis of renal cell carcinoma. Understanding of the molecular genetics of renal tumors is beneficial in making accurate diagnoses, assessing prognoses, and selecting appropriate and targeted therapeutic options.

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.

Mucinous tubular and spindle cell carcinoma of the kidney with sarcomatoid change

Sarcomatoid change has been well documented in the various subtypes of renal cell carcinoma (RCC) and its presence is known to portend a worse prognosis in RCC. Mucinous tubular and spindle cell carcinoma is a RCC subtype, which is defined as polymorphous histology wherein the spindled epithelial cell is an inherent carcinomatous component. Many of these putatively low-grade tumors have been previously misdiagnosed as unclassified or sarcomatoid papillary RCC. We present 2 examples of hitherto undescribed sarcomatoid change in mucinous tubular and spindle cell carcinoma in a 71-year-old woman and an 80-year-old man who both underwent a radical nephrectomy procedure. In addition to the classic mucinous tubular and spindle cell carcinoma morphology, both cases had a sarcomatoid component characterized by predominantly high-grade spindle cells, solid pleomorphic epithelioid cells, and malignant fibrous histiocytoma-like storiform patterns. Sarcomatoid change comprised 60% and 20% of the tumors, respectively. Unlike the spindle sarcomatoid cells, the inherent spindle cell elements of mucinous tubular and spindle cell carcinoma had distinctively low-grade cytology and occasionally blended with tubular structures and variable mucinous stroma. The sarcomatoid cells were associated with significant necrosis, marked nuclear pleomorphism, mitoses of up to 5/10 high power field, higher proliferation fraction (MIB1), and loss of alpha-methylacyl-CoA racemase or cytokeratin 7 expression. Cytogenetic analysis in 1 tumor showed loss of chromosomes 14 and 15 and gains of chromosomes 2, 5, 7, 9, 10, 12, 17, 19, 20, 22, and X. Widespread metastasis to lymph nodes, bones and lungs occurred in one patient who succumbed 9 months after nephrectomy. Helpful features in distinguishing spindle cells of sarcomatoid component versus that of the native tumor include the presence of high-grade cytology, expansile growth with loss of typical imperceptible blending with the tubulo-papillary component, extensive necrosis, high mitotic activity, high proliferation fraction, and loss of expression of alpha-methylacyl-CoA racemase that contrasted the classic areas. Distinction of the sarcomatoid histology from inherent spindle cell component of mucinous tubular and spindle cell carcinoma is important because of its unfavorable prognostic implication.

Molecular and cytogenetic insights into the pathogenesis, classification, differential diagnosis, and prognosis of renal epithelial neoplasms

Renal cell carcinomas comprise a heterogeneous group of epithelial neoplasms with diverse biologic potential and variable clinical outcomes. The application of molecular and cytogenetic techniques to the study of renal neoplasms has improved our understanding of the molecular mechanisms responsible for tumor initiation and progression. Molecular classification of renal cell carcinomas has also provided new avenues for diagnosis, clinical outcome, and therapy response prediction. In this article, we review the molecular markers for various renal epithelial neoplasms and discuss the mechanisms underlying the development of these neoplasms. We also evaluate the use of molecular and cytogenetic techniques in establishing an accurate diagnosis in difficult cases and their potential usefulness in accurately classifying renal neoplasms, assessing prognosis, and selecting appropriate therapy.

[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.