Primary synovial sarcoma of the kidney

Synovial Sarcoma of the Kidney: Diagnostic Pitfalls in a Case with Myxoid Monophasic Differentiation and No Epithelial Biomarkers Expression

Synovial sarcomas are soft tissue tumours of uncertain origin, most commonly found in the upper or lower extremities. They are characterised by distinctive chromosomal rearrangements involving the gene SS18. Synovial sarcomas can occasionally arise also in visceral sites, but retroperitoneal SSs are very unusual. Among them, a few primary renal synovial sarcomas have been described in the scientific literature. Primary renal synovial sarcomas tend to be monophasic and often show cystic changes. Histologically, they can closely resemble other primary kidney tumours, mainly paediatric tumours such as nephroblastoma and clear cell sarcoma of the kidney. In the current work, a primary synovial sarcoma of the kidney with unusual morphological features (extensively myxoid stroma and immunohistochemical positivity for BCOR) is described. Molecular analysis, through targeted RNA sequencing, was of invaluable help in reaching the correct diagnosis. Despite locally advanced disease at presentation, the patient showed an unexpectedly brilliant response to chemotherapy.

Primary Synovial Sarcoma of the Kidney: Diagnostic Approach and Therapeutic Modalities for a Rare Nosological Entity

Synovial sarcoma (SS) is a rare mesenchymal entity that represents 5–10% among soft tissue sarcomas (STS). Primary renal synovial sarcoma (PRSS) is an uncommon, rapidly growing tumor, with potential metastatic dissemination. The main prognostic factors of PRSS include tumor size and histologic grade, while translocation t (X; 18) (p11.2; q11.2) (fusion of SYT gene -chromosome 18- with SSX genes (1, 2 or 4)-chromosome X) is the most common pathognomonic sign. Aggressive surgical resection of the tumor along with concomitant regional lymphadenectomy is the treatment of choice for PRSS, while additional en bloc resection of the adjacent affected organs is often performed. To date, the role of preoperative or postoperative chemotherapy remains equivocal. The prognosis of patients with PRSS is poor, as the 5-year survival rate is only 20–30% and further deteriorates when a high mitotic activity is detected. Local recurrence even after complete R0 surgical excision remains the most frequent cause of death. The aim of this review was to meticulously discuss clinical features, histogenesis, and morphological and immunochemical findings of PRSS, while the role of current diagnostic and therapeutic management of this aggressive neoplasm was emphasized.

Knowledge of cytogenetic analysis for synovial sarcoma in sarcomatoid variant renal cell carcinoma

Sarcomatoid change in a renal tumor should undergo cytogenetic analysis of t(x;18) to prevent a missed diagnosis of synovial sarcoma. Surgeons should be vigilant regarding pathological correlation.

Primary Renal Synovial Sarcoma Presenting as Haemorrhagic Shock: A Rare Presentation

Primary synovial sarcoma (PSS) of the kidney is considered the rarest type of all renal sarcomas with specific chromosomal translocation t (X; 18) (p11.2; q11.2). We report the case of a 65-year-old man with no medical conditions who presented to the emergency department with sudden severe right flank pain associated with haemodynamic instability and haemorrhagic shock. Computed tomography (CT) of the abdomen and pelvis revealed a right renal mass. A right open radical nephrectomy was performed. Histopathology revealed a monophasic synovial sarcoma. The patient received six cycles of docetaxel and gemcitabine as adjuvant chemotherapy. No sign of recurrence was seen on a follow-up CT urogram. This rare tumour often presents atypically, and clear guidelines regarding appropriate treatment are lacking. Our case showed that treatment with docetaxel/gemcitabine after an open radical nephrectomy is promising.

Primary Renal Synovial Sarcoma and Clinical and Pathological Findings: a Systematic Review

PURPOSE OF REVIEW

To update epidemiological, diagnostic, and therapeutic information on primary synovial sarcoma of the kidney.

RECENT FINDINGS

A total of 96 studies were analyzed; age at presentation was 38.6±14.2 years, predominant location of tumor was right kidney; frequent reported symptoms at diagnosis were hematuria and pain. For definitive diagnosis, cytogenetic technique was used. Detected oncogene was available in 37.8% cases with fusion of SS18-SSX in most patients. Surgery is treatment of choice, with adjuvant chemotherapy; most frequently ifosfamide-based associated with doxorubicin or epirubicin. Overall median survival was 34 months. Mortality was 29% of the cases which reported death and the recurrence rate was 39.8%. Risk of death was increased in patients with metastases at diagnosis Primary RSS occurs more often in young men. RSS often presents with symptoms and in an advanced stage. Surgical treatment is the most commonly used and chemotherapy for advanced or recurrent treatment.

Primary Intraosseous Synovial Sarcoma with Molecular Confirmation: Expanding and Clarifying the Spectrum of This Rare Neoplasm

Synovial sarcoma is a well-known malignant tumor usually originating within deep soft tissues of the lower extremities of adolescents and young adults. Rare radiologically confirmed examples of primary bone synovial sarcoma have been documented, generally in isolated case reports. Herein, we report two cases of primary intraosseous synovial sarcoma, with molecular confirmation, involving the left humerus of a 45-year-old female and the right fourth metatarsal bone in a 36-year-old male. Additionally, we clarify the spectrum of primary intraosseous synovial sarcoma by separately analyzing reported cases with radiographic confirmation of bone origin and molecular support for the diagnosis. There are clinicopathologic differences between those tumors with documented molecular confirmation and those lacking such confirmation, specifically regarding their anatomic distribution (p < 0.0001). Regarding the radiology of our two cases, the humeral lesion appeared almost entirely intramedullary without soft tissue extension; the midfoot lesion demonstrated a destructive, metatarsal-centered bone lesion, initially thought clinically to represent primary bone osteosarcoma. The diagnoses of monophasic synovial sarcoma were rendered via core needle biopsies, with molecular FISH confirmation of SYT gene rearrangement. Clinical follow-up data was only available for the female patient with the primary humeral lesion, who underwent surgical resection, with no local recurrence or distant metastasis at 7 months postsurgery. To our knowledge, these are the first reported examples of molecularly confirmed, primary intraosseous synovial sarcomas of the humerus and metatarsal bones. Primary intraosseous synovial sarcomas with molecular confirmation differ clinically from those lacking it; however, the demographic features and metastatic potential appear similar to primary soft tissue synovial sarcoma.

Primary synovial sarcoma of the kidney: a case report of complete pathological response at a Lebanese tertiary care center

Background

Primary synovial sarcoma of the kidney is a rare type of soft tissue sarcoma. Its presenting features can resemble those of other renal tumors; rendering its early diagnosis, a dilemma. Several cases of renal synovial sarcoma have been reported in the literature with varying treatment options and outcomes. This article describes a rare case of primary renal synovial sarcoma and reviews all cases in the literature.

Case presentation

A 26-year-old male presented with flank pain and hematuria. Initially diagnosed with Wilm’s tumor, revision of pathology and histology, along with the immunohistochemical profile, confirmed, nevertheless, the diagnosis of primary monophasic synovial sarcoma of the kidney with the SYT-SSX2 fusion transcript. Follow-up, post nephrectomy, revealed recurrence within the lungs and at the surgical bed. Surgical resection followed by adjuvant chemotherapy regimen constituting of Doxorubicin and Ifosfamide, achieved complete pathological response.

Conclusion

In this case report, we emphasize the need for accurate diagnosis and prompt treatment. We propose multimodality treatment approach including surgery along with anthracycline-based chemotherapy to induce complete remission.

mASH1 is Highly Specific for Neuroendocrine Carcinomas: An Immunohistochemical Evaluation on Normal and Various Neoplastic Tissues

CONTEXT

-High-grade neuroendocrine carcinomas and carcinoids can arise in different sites such as lung, gastrointestinal tract, prostate, and skin. Classic neuroendocrine markers such as CD56, synaptophysin, and chromogranin cannot distinguish carcinoids from high-grade neuroendocrine carcinomas. Recently, mouse monoclonal mASH1 has been shown to help discriminate carcinoids from high-grade neuroendocrine carcinomas in various neoplastic sites. To date, there have been no comprehensive immunohistochemistry studies with mASH1 on nonneuroendocrine neoplasms.

OBJECTIVE

-To evaluate the specificity and sensitivity of mASH1 in various normal and neoplastic tissues, including lung cancers.

DESIGN

-Formalin-fixed, paraffin-embedded tissue microarrays consisting of normal tissues and various neoplastic tissues were immunohistochemically evaluated with mASH1.

RESULTS

-In normal tissues (n = 30), mASH1 (nuclear staining) was sparsely expressed in the molecular cell layer, white matter, and granular cell layer of cerebellum; C cells in thyroid; and epithelial cells in thymus. In lung cancers, mASH1 stained 1.1% (1 of 93) of adenocarcinomas, 0.9% (1 of 111) of squamous cell carcinomas, 0% (0 of 30) of large cell carcinomas, 66.7% (6 of 9) of large cell neuroendocrine carcinomas, and 82.5% (94 of 114) of small cell carcinomas. In various other neoplastic tissues (n = 1114), mASH1 was expressed in thyroid medullary carcinomas, thymic carcinomas, and brain cancers; mASH1 was also expressed in a very low percentage of breast carcinomas, ovarian cancers, and pancreatic neuroendocrine tumors. All typical carcinoids of various sites were negative (0 of 11), however, in lung atypical carcinoids, mASH1 was expressed in 42.9% (9 of 21).

CONCLUSIONS

-Although not organ specific, mASH1 is highly specific for high-grade neuroendocrine carcinomas versus carcinoids and other nonneuroendocrine neoplasms.

A case report of one of the largest {3.63kg} renal tumour removed in the Western Hemisphere. A combined Uro vascular approach for complete removal

INTRODUCTION

This paper describes the technique employed for the removal of the largest renal tumour in the Western Hemisphere and the second largest in the World. It is a road map for Surgeons in Training and should be of interest to other Surgeons/Urologists. This tumour weighed 3.63kg; the world's largest weighed 5.44kg.

PRESENTATION OF CASE

A 52year old male presented with a one year history of progressive weight loss, a gradually enlarging abdomen and no other admissible symptom, including no haematuria. The mass started on his left side of the abdomen. CT scans showed a large tumour arising from the left kidney.

DISCUSSION

A combined Urological and vascular approach was chosen in view of the CT scans images of huge renal veins and collateral vessels. The left pleural cavity was elevated by the mass pushing on the left diaphragm and the heart was also displaced cranially as the mass made its own space. Bowels were displaced as the giant mass reached into his pelvis. A thoraco abdominal supra12 rib bed approach was adopted. The rib was not resected nor was the pleural cavity opened. Histological diagnosis was renal leiomyosarcoma.

CONCLUSION

Large renal tumours or masses are best approached by the Urologist with an experienced vascular/general surgeon as assistant as well as a skilled anesthetist/Intensivist. Optimisation, critical care and early mobilization of the patient by a dedicated nursing staff are essential to minimize complications and ensure a successful end result. The success of this operation underscores what is possible in developing countries.

Synovial sarcoma of kidney in a child: A rare presentation

There are no reported cases in the literature of primary renal synovial sarcoma in pediatric patients. The management of renal synovial sarcoma has been extrapolated from the management of soft tissue sarcomas at other sites. We present a 4-year-old female who was suspected to have Wilms’ tumor. The patient underwent guided biopsy as she did not respond to neoadjuvant chemotherapy for Wilms’ tumor. The biopsy was consistent with primary renal synovial sarcoma. The child was treated with change in her neoadjuvant chemotherapy regimen and surgery. The diagnosis of synovial sarcoma was confirmed by demonstrating the t (X, 18) translocation using polymerase chain reaction.

Clear cell sarcoma of the kidney distinguished from synovial sarcoma using genetic analysis: a case report

Background

The most common pediatric renal neoplasm is Wilms tumor, but clear cell sarcoma of the kidney or synovial sarcoma of the kidney are also sometimes encountered. Accurate pathological diagnosis is important, because adjuvant therapies including chemotherapy and radiotherapy differ according to the pathological type.

Case presentation

A 9-year-old boy presented with a headache, and ultrasonography, computed tomography, and magnetic resonance imaging revealed a heterogeneous enhancement of soft tissue originating from the upper pole of the left kidney, measuring approximately 11.0 × 10.0 × 8.0 cm. A left radical nephrectomy was performed using an intraperitoneal approach through an anterior subcostal incision. Pathological examination suggested clear cell sarcoma of the kidney or synovial sarcoma of the kidney based on morphological and immunohistological features. Using genetic analysis, a final diagnosis of spindle cell pattern clear cell sarcoma of the kidney was made based on the absence of the SYT-SSX fusion gene. After adjuvant chemo-radiotherapy was administered, no recurrence or metastasis has been identified as of 60 months postoperatively.

Conclusion

In this case, it was difficult to discriminate clear cell sarcoma of the kidney from synovial sarcoma of the kidney based on histopathological examination alone, and genetic analysis was required. Accurate pathological diagnosis of pediatric renal tumor is important for determining optimal treatment and preventing recurrence and metastasis.

Primary synovial sarcoma of kidney: a rare differential diagnosis of renomegaly

Synovial sarcomas (SS) are classified as subgroup of soft tissue sarcomas affecting mainly extremities of young adults. Primary SS of kidney are very rare tumours with poor prognosis. Though they have characteristic histology and immunohistochemistry (IHC) due to rarity of incidence it is difficult to diagnose them. Sometimes chromosomal rearrangement studies are required to confirm the diagnosis. We are presenting a case of 41-year-old male who was referred to our cancer centre for evaluation of left renal mass. CT scan of abdomen revealed a large left renal mass encasing the aorta. Biopsy of renal mass revealed poorly differentiated sarcoma and IHC was positive for vimentin, CD99, and BCL2 and negative for AE1, epithelial membrane antigen, and leukocyte common antigen. The patient was clinically inoperable as renal mass was encasing the aorta. So he was subsequently offered palliative chemotherapy in form of ifosfamide and adriamycin. CT abdomen shows partial response after 3 cycles of chemotherapy according to RECIST criteria.

Metanephric adenosarcoma: a rare case with immunohistochemistry and molecular analysis

Background

Metanephric neoplasms comprised a spectrum of kidney tumors containing renal epithelial or stromal cells or both, including metanephric adenoma, metanephric stromal tumor, and metanephric adenofibroma. The majority of cases were benign; only one case of “metanephric adenosarcoma” had been reported in the English literature.

History

We present the case of a 69-year-old man who developed a neoplasm composed of renal epithelial component identical to metanephric adenoma combined with malignant spindle-cell stroma. The epithelial component was positive for CD57, AE1/AE3, but negative for WT-1, CD56, SYN, and CgA; whereas the sarcomatous component was negative for epithelial markers, SMA, Caldesmon, MyoD1, Myogenin, and S-100; and positive for vimentin, CD10, and WT1 focally. No specific sarcoma differentiation was apparent in the stroma by immunohistochemistry, and no SYT-SS18 rearrangement or BRAF mutation was detected by molecular analysis.

A diagnosis of metanephric adenosarcoma was made because of the morphological features and immunohitochemistry and molecular pathology analysis.

Clinical significance

We believe that metanephric adenosarcoma should be in the expanded spectrum of metanephric neoplasia as a malignant stromal variant.

Conclusions

We report a rare case of metanephric adenosarcoma with immunohistochemistry and molecular analysis and emphasize the histopathologic features and differential diagnosis of the rare lesion to promote a better and broader understanding of this less understood subject.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_179

Primary Renal Synovial Sarcoma: An Oncologic Surprise

Primary renal synovial sarcoma is a rare tumor having a specific chromosomal translocation t(X; 18) (p11.2; q11.2). The clinical features of this tumor and radiologic appearances are quite similar to those of renal cell carcinoma. Confirmatory diagnosis requires fluorescent in situ hybridization or reverse transcriptase polymerase chain reaction validation for differentiating the tumors from sarcomatoid renal cell carcinoma. We present a case of primary renal synovial sarcoma that was diagnosed in a middle-aged man.

Primary synovial sarcoma of the prostate metastatic to the liver and lung: a case report

Primary synovial sarcoma of the prostate is an uncommon malignant tumor. There are few cases reported in the English medical literature to date. Here, we present a case of 22-year-old man with primary synovial sarcoma of the prostate metastatic to the liver and lung. To our knowledge, only six reports of synovial sarcoma involving the prostate have been previously published. We also reviewed the previous treatments and prognoses in previous case reports and evaluate the proper treatment for this disease.

The value of immunohistochemistry in diagnosing primary renal synovial sarcoma: a case report and literature review

Primary synovial sarcoma of the kidney is rare and difficult to diagnose with 100% accuracy without the use of up-to-date histopathologic methods. Immunohistochemical procedures are well established and are continuously expanding and improving. Currently, these methods are successful in up to 90% of tumor identification. The remaining cases will ultimately benefit by combining immunohistochemistry with tumor-specific genetic marker identifiers, the latter of which are increasing in availability for tumor diagnosis. The principal immunohistochemical methods enlisted in establishing a diagnosis of primary renal synovial sarcoma are summarized.

Spectrum of preneoplastic and neoplastic cystic lesions of the kidney

CONTEXT

Cystic lesions of the kidney may be accompanied by a range of neoplasms with distinct prognoses and future risks of developing additional tumors. In addition, some renal tumors, with or without accompanying renal cysts, may show a prominent cystic component. In the adult population, neoplasms occurring in a background of renal cystic diseases and cystic renal neoplasms often pose diagnostic challenges because of their many overlapping features.

OBJECTIVE

To review the clinicopathologic characteristics of common entities in the spectrum of neoplastic and potential preneoplastic cystic lesions encountered in adults, with an emphasis on renal cystic diseases associated with tumor development and on renal neoplasms with predominantly cystic morphology.

DATA SOURCES

The relevant English-language literature was reviewed, accompanied by the authors' experience at their practicing institution.

CONCLUSIONS

The presence of multiple renal cysts, both acquired and syndromic, can be associated with a variety of renal tumors. The morphology of the cysts and associated tumor types can help predict the genetic or acquired basis of the lesions, and particularly in specimens with no accompanying pertinent clinical history, such potential associations should be suggested in surgical pathology reports.

Inhibin-α and synaptophysin immunoreactivity in synovial sarcoma with granular cell features

We recognized immunoreactivity for the α subset of inhibin and synaptophysin in synovial sarcomas with granular cell features. Histologic findings of 90 cases of synovial sarcoma were reviewed. Two (2.2%) of the 90 cases had granular cell features, showing sheet or nested proliferation of characteristic epithelioid cells with abundant eosinophilic and granular cytoplasm, in addition to the typical spindle cell component. The 2 cases were both female (aged 86 and 76 years). The tumors were located in the foot and the retroperitoneum and measured 3.5 and 14 cm in maximum diameter. Reverse transcriptase polymerase chain reaction analysis revealed SS18-SSX1 transcripts in both cases. SS18 gene rearrangement was detected in granular cells as well as spindle cells by chromogenic in situ hybridization. Immunohistochemistry found the granular cells to be positive for inhibin-α in both cases and for synaptophysin in 1 case, whereas spindle cells were not. Thirty-six cases (20 monophasic fibrous, 11 biphasic, and 5 poorly differentiated synovial sarcomas) were additionally examined for comparison; they showed no immunoreactivity for inhibin-α or synaptophysin. This is the first report of immunoreactivity for inhibin-α and synaptophysin in synovial sarcoma. These immunohistochemical findings might be characteristic of synovial sarcomas with granular cell features.

Primary renal synovial sarcoma in a 13-year-old boy

Primary renal synovial sarcoma is a rare entity with fewer than 40 cases reported in the literature. Its clinical presentation and radiographic features, namely, its often complex cystic appearance, make it difficult to differentiate from other benign or malignant renal lesions. Although there are certain consistent morphological and immunohistochemical features, diagnosis ultimately depends on molecular studies. Prognosis is poor, and there currently exists no defined treatment protocol. Herein, we describe the youngest reported case of primary renal synovial sarcoma in the literature.

Primary renal synovial sarcoma

Primary synovial sarcoma (SS) of kidney is very rare and difficult to diagnose. Here, we present a case of a 21-year-old female clinically diagnosed as renal cell carcinoma. Right nephrectomy specimen showed a cystic tumor in the upper pole of kidney with areas of hemorrhage and solid growth. Histologically, it showed poorly differentiated cells with hemangiopericytoma-like vascular pattern. Morphologic and immunohistochemical features were compatible with the diagnosis of poorly differentiated SS of kidney. Primary renal SS is a recently described entity. To the best of our knowledge, approximately 34 cases have been reported till date and this is the eighth documented case of poorly differentiated variant. Most of the time, poorly differentiated SS of kidney exhibits hemangiopericytoma like histology. Reverse transcriptase-polymerase chain reaction analysis to demonstrate SYT-SSX fusion gene transcript helps to confirm the diagnosis.

Molecular approaches to sarcoma therapy

Soft tissue sarcomas comprise a heterogeneous group of aggressive tumors that have a relatively poor prognosis. Although conventional therapeutic regimens can effectively cytoreduce the overall tumor mass, they fail to consistently achieve a curative outcome. Alternative gene-based approaches that counteract the underlying neoplastic process by eliminating the clonal aberrations that potentiate malignant behavior have been proposed. As compared to the accumulation of gene alterations associated with epithelial carcinomas, sarcomas are frequently characterized by the unique presence of a single chromosomal translocation in each histological subtype. Similar to the Philadelphia chromosome associated with CML, these clonal abnormalities result in the fusion of two independent unrelated genes to generate a unique chimeric protein that displays aberrant activity believed to initiate cellular transformation. Secondary gene mutations may provide an additional growth advantage that further contributes to malignant progression. The recent clinical success of the tyrosine kinase inhibitor, STI571, suggests that therapeutic approaches specifically directed against essential survival factors in sarcoma cells may be effective. This review summarizes published approaches targeting a specific molecular mechanism associated with sarcomagenesis. The strategy and significance of published translational studies in six distinct areas are presented. These include: (1) the disruption of chimeric transcription factor activity; (2) inhibition of growth stimulatory post-translational modifications; (3) restoration of tumor suppressor function; (4) interference with angiogenesis; (5) induction of apoptotic pathways; and (6) introduction of toxic gene products. The potential for improving outcomes in sarcoma patients and the conceptual obstacles to be overcome are discussed.

So-called 'adenosarcoma' of the kidney a novel adult renal tumor with a cystic appearance

We describe a novel cystic renal tumor consisting of benign epithelial and malignant stromal components in a 56-year-old woman who was admitted to hospital with macroscopic hematuria. Enhanced computed tomography revealed a multilocular 3.4 × 2.7-cm tumor in the center of the left kidney. After total left nephrectomy, the excised tumor appeared extensively cystic with a well defined border on the cut surface. Histologically, the tumor was composed of biphasic a benign epithelial lining on tubules or cysts with a typically hobnailed appearance, and anaplastic sarcomatous stroma with frequent mitosis. Periepithelial cuffing of the sarcoma cells was evident without an epithelial-stromal transition. Carcinomatous nests, blastemic elements, ovarian-like stroma or differentiated mesenchyme were not evident in the stroma. The epithelial cells were reactive with cytokeratins, epithelial membrane antigen (EMA), vimentin and transducin-like enhancer protein 1 (TLE1). Stromal cells were reactive with vimentin, CD99 and TLE1, partly reactive with CD34 and CD10, and non-reactive with cytokeratins, EMA, Wilm's tumor protein (WT-1), estrogen receptor (ER), progesterone receptor (PgR), CD57, HMB45 or Bcl2. SYT-SSX fusion gene was not detected with reverse transcription polymerase chain reaction. Because these findings did not coincide with established descriptions of cystic renal neoplasms, we preferred the term, 'adenosarcoma'. This could become a new classification for adult cystic renal tumors.

A case of renal synovial sarcoma treated with adjuvant ifosfamide and doxorubicin

Primary renal synovial sarcomas (SS) are rare tumors of the kidney. Faria et al first described primary renal synovial sarcoma in 1999 (Mod Pathol 12:94A). In this paper we present a primary renal synovial sarcoma case and review the 41 primary renal synovial sarcoma cases reported to date. Primary renal synovial sarcomas can exist in either a monophasic or a biphasic pattern. The monophasic variant of primary renal synovial sarcoma is more common and tends to have a better prognosis than the biphasic variant. We present in this paper, a 68-year-old woman with primary renal synovial sarcoma. She presented with right flank pain and abdominal distention. Postoperative pathology of the 20 cm mass on magnetic resonance imaging showed histologic and immunochemical features of synovial sarcoma with coexisting spindle and epithelial cells. She underwent adjuvant ifosfamide and doxorubicin chemotherapy and was free of disease at 1 year after diagnosis. As a conclusion, physicians should be aware of the possibility of malignancy in cystic renal masses and that synovial sarcoma is one of the possibilities.

Cystic renal tumors: new entities and novel concepts

Cystic renal neoplasms and renal epithelial stromal tumors are diagnostically challenging and represent some novel tumor entities. In this article, clinical and pathologic features of established and novel entities are discussed. Predominantly cystic renal tumors include cystic nephroma/mixed epithelial and stromal tumor, synovial sarcoma, and multilocular cystic renal cell carcinoma. These entities are own tumor entities of the 2004 WHO classification of renal tumors. Tubulocystic carcinoma and acquired cystic disease-associated renal cell carcinoma are neoplasms with an intrinsically cystic growth pattern. Both tumor types should be included in a future WHO classification as novel entities owing to their characteristic features. Cysts and clear cell renal cell carcinoma frequently coexist within the kidneys of patients with von Hippel-Lindau disease. Sporadic clear cell renal cell carcinomas often contain cysts, usually as a minor component. Some clear cell renal cell carcinomas have prominent cysts, and multilocular cystic renal cell carcinoma is composed almost exclusively of cysts. Recent molecular findings suggest that clear cell renal cancer may develop through cyst-dependent and cyst-independent molecular pathways.

Primary Synovial Sarcoma of the Kidney

The case was a 40-year-old female. She visited a local doctor with a chief complaint of right side abdominal pain. A right kidney tumor measuring 10 cm in diameter was observed in an abdominal Computed Tomography (CT) scan. Based on the CT image, the possibility of angiomiolipoma (AML) could not be ruled out, but a high maximum standardized uptake value (SUVmax) of 7.8 was observed in a Positron Emission Tomography CT (PET-CT) scan and there was a possibility of malignancy. We therefore performed a transperitoneal right radial nephrectomy. Although adhesion of the tumor to the duodenum and the inferior vena cava was observed, it was possible to perform an excision. The tumor accounted for a large proportion of the excised kidney; the surrounding areas had taken on a cyst-like structure, and the interior comprised grayish brittle tissue exhibiting solid growth. Histologically, gland-like and cyst-like structures composed of cylindrical cuboidal cells and mainly characterized by the solid growth of short fusiform-shaped and oval-shaped basophilic cells were observed, and we believed it was a synovial sarcoma. There were no malignant findings in the adrenal gland. There have been approximately 30 reported cases around the world of synovial sarcoma that developed in the kidney, and we herein report this case with bibliographic considerations.

Mixed epithelial and stromal tumors of the kidney: an overview

Mixed epithelial and stromal tumor of the kidney is a recently recognized distinct neoplasm that should be distinguished from other renal neoplasms. These tumors are relatively rare with a female preponderance. Imaging studies are not diagnostic but reveal a solid or solid and cystic mass in most cases. Histopathologically, these tumors reveal biphasic growth pattern comprising mesenchymal and epithelial elements with characteristic estrogen and progesterone receptor immunoreactive mesenchyme reminiscent of ovarian stroma. Malignant transformation, recurrence, and metastasis are rare; however, recently a few cases of malignant mixed epithelial and stromal tumors have been reported in the literature. Recently a case with translocation t(1;19) has been described. This article provides a brief overview of the current knowledge of mixed epithelial and stromal tumor of the kidney.

Synovial sarcoma of the kidney

The renal parenchyma is a rare site of origin for primary synovial sarcoma (SS). The present study describes the clinicopathologic, immunohistochemical, and molecular analysis of 7 cases of SS occurring in the kidney. There were 5 female and 2 male patients, with an age range of 15 to 46 years. They presented with solitary renal masses ranging in size from 10.0 cm to 17.0 cm in greatest dimension. Radical nephrectomy was performed in all cases. On gross examination, tumors were large, partially necrotic, and were seen to contain smooth-walled cysts in 4 cases. Histologically, the tumors were characterized by monomorphic spindle cells with indistinct cell borders arranged in intersecting nodular foci with hypocellular myxoid areas, together with a prominent hemangiopericytomatous pattern. The cysts were lined by hobnailed cells with eosinophilic cytoplasm. Immunohistochemically, BCL-2 was positive in all 6 cases in which it was performed, followed by vimentin (4/5 cases), MIC2 (CD99; 2/5 cases), calponin (2/2 cases), and epithelial membrane antigen (1/4 cases). Stains for cytokeratin and CD34 were consistently negative. Reverse transcription-polymerase chain reaction (RT-PCR) using RNA extracted from formalin-fixed paraffin-embedded tissues was carried out in 4 cases and SYT-SSX fusion gene transcript, which is the diagnostic hallmark of SS, was detected. Two patients developed pulmonary metastasis and died 6 and 12 months after diagnosis, respectively. This series of cases is distinct in terms of its morphological spectrum and confirmation by molecular technique.

Immunohistochemical profiling of Wilms tumor: a tissue microarray study

AIM

Wilms tumor (WT) usually shows a bi-phasic or tri-phasic morphology comprised of blastemal, stromal, and epithelial cells. Other biphasic renal tumors that can mimic WT may pose diagnostic dilemmas especially in preoperative needle biopsy samples. This tissue microarray study was designed to investigate the immunohistochemical features that may prove useful in the accurate diagnosis of WT in small biopsy samples.

METHODS

Eight punches from each paraffin block of 45 cases of WTs were used to construct 5 tissue microarray blocks. Immunohistochemical reactions of blastemal, stromal, and epithelial cells of each core to a panel of 37 antibodies were evaluated.

RESULTS

Blastemal elements expressed CD56 (22, 57%), CD57 (19, 55%), cytokeratin 22 (CK22) (12, 27%), and CK8 (9, 21%). Epithelial cells were stained mostly with CK22 (17, 94%), CK18 (12, 66%), CK8 (14, 70%), CD57 (10, 76%), CD56 (6, 43%), EMA (7, 44%), and CK19 (5, 25%). Stromal cells expressed SMA (21, 50%), actin (18, 48%), desmin (9, 20%), CD34 (7, 24%), CD57 (5, 18%), and CD56 (5, 15%). Only one case was positive for CK5/6, CK13, CK14, and CK20. Calretinin expression was seen in the stromal cells of 3 and placental alkaline phosphatase expression was observed in 1 case. All 3 components were negative for CK1, CK7, myoglobin, Myf-4, MyoD1, HMB45, chromogranin A, synaptophysin, Melan A, beta-HCG, alpha-HCG, alpha-Inhibin, renal cell carcinoma antigen, glycophorin A, PSA, and estrogen and progesterone receptors.

CONCLUSIONS

CD56, CD57, CK22, CK18, CK8, EMA, SMA, and actin are useful markers for an accurate diagnosis of WT in small biopsy samples.

Primary synovial sarcoma of the kidney

Primary synovial sarcoma arising from the kidney is extremely rare. We report two cases with primary renal synovial sarcoma. Both were initially diagnosed as renal cell carcinoma. The first case was a 30-year-old woman who presented with right flank soreness. Ultrasonography disclosed a multiloculated cystic tumor measuring 9 x 7 cm. She underwent hand-assisted laparoscopic radical nephrectomy; there was no recurrence during 15 months of follow-up. The second case was a 49-year-old woman who presented with a palpable mass in the left upper quadrant of the abdomen of 1 month's duration. Computed tomography showed a heterogeneously enhanced tumor measuring 13 x 11 cm at the left retroperitoneum with displacement of the pancreas and the left kidney. Hand-assisted retroperitoneoscopic radical nephrectomy was performed. She had no evidence of recurrence after 27 months of follow-up. Pathology of the two cases showed histologic and immunochemical features of synovial sarcoma with coexisting spindle and epithelial cells. Physicians should be aware of the possibility of malignancy in cystic renal masses and that synovial sarcoma is one of the possibilities.

The diagnostic value of SYT-SSX detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH) for synovial sarcoma: a review and prospective study of 255 cases

This study aimed to evaluate the diagnostic value of SYT-SSX detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH) for synovial sarcoma (SS) in known and potential cases. SYT-SSX was analyzed in formalin-fixed, paraffin-embedded tissues of 62 known SS, 60 non-SS and 133 potential SS by RT-PCR and FISH. FISH was mainly performed on a tissue microarray with some modifications. SYT-SSX was detected in 94.7% (54/57) of known SS and 70.5% (86/122) of potential SS by RT-PCR and in 96.7% (58/60) of known SS and 78.1% (100/128) of potential SS by FISH. Moreover, SYT-SSX was negative in 100% (58/58) of non-SS by RT-PCR and in 100% (59/59) of non-SS by FISH. Accordingly, SYT-SSX was detected in 106 potential SS by RT-PCR or FISH, including 80 cases manifested by both methods, 20 specimens verified only by FISH and 6 samples confirmed only by RT-PCR. Clinical findings and immunohistochemistry data were analyzed in potential SS with final molecular diagnosis. The positive ratio of cytokeratin (CK) and epithelial membrane antigen (EMA) in finally diagnosed SS was 51.9% (55/106) and 61.3% (65/106), respectively. Except EMA, clinical parameters (age, sex, tumor size, tumor sites) and other immunohistochemistry indexes (CK, S-100, neurone specific enolase (NSE), CD99, myoglobin, smooth muscle actin (SMA), cluster of differentiation (CD) 68 and mesothelial cell) had no significant difference between finally diagnosed SS and non-SS. It is indicated that the efficiency of FISH is comparable to or even higher than that of RT-PCR for SYT-SSX detection. The detection of SYT-SSX by RT-PCR or FISH is very useful for the final diagnosis of potential synovial sarcomas.

Mixed epithelial and stromal tumor of kidney with malignant transformation: report of two cases and review of literature

We present 2 cases of mixed epithelial and stromal tumor of the kidney with sarcomatous transformation. One patient was a 53-year-old woman who presented with macroscopic hematuria. The resected tumor involved the right renal parenchyma, measuring 13.0 x 8.0 x 4.0 cm, and extended to perirenal adipose tissue. The second patient was a 56-year-old woman who presented with right flank colic pain. The tumor measured 6.0 x 5.5 x 4.0 cm, with an intact capsule at the upper pole. Both tumors showed a well-circumscribed, multilocular, cystic, and focally solid mass. Sections of both tumors revealed benign and malignant components. The benign component consisted of multilocular cysts and fibrous stroma with a focally ovarian stromalike component. The malignant component in both cases was predominantly composed of undifferentiated cellular spindle cell sarcoma with frequent mitoses. One case showed additional heterologous malignant elements, including rhabdomyosarcomatous, chondrosarcomatous, and focal carcinomatous components. We report 2 additional cases of sarcomatous transformation in mixed epithelial and stromal tumor of the kidney.

Primary synovial sarcoma of the kidney with rhabdoid features

Synovial sarcoma is a soft tissue sarcoma with clearly defined histologic, immunophenotypic, and molecular features. It occurs predominantly in the extremities of young adults but has been reported in many other anatomic sites. Histologically, it is classified as biphasic, monophasic, and poorly differentiated. The latter category, which includes tumors with a rhabdoid morphology, has been associated with a more aggressive behavior. Generally, the biphasic variant does not pose any diagnostic problem because of its typical histologic appearance; in contrast, the monophasic and poorly differentiated variants may represent a diagnostic challenge because their microscopic features can be confused with those of other spindle cell tumors with rhabdoid features. The application of molecular techniques, such as reverse transcriptase polymerase chain reaction to detect the fusion transcript associated with the characteristic t(X;18) translocation of synovial sarcoma, has enabled the confirmation of this diagnosis, even in cases of unusual localization, such as the one we present here.

Cystic nephroma and mixed epithelial and stromal tumour of the kidney: opposite ends of the spectrum of the same entity?

OBJECTIVES

The term "renal epithelial and stromal tumour" (REST) was proposed recently to encompass the spectrum of findings observed in cystic nephroma (CN) and mixed epithelial and stromal tumour (MEST) of the kidney. Our aim was to review the broad spectrum of usual and unusual clinical and morphologic findings observed in CN and MEST.

METHODS

Based on Medline database searches, all aspects of CN and MEST were assessed.

RESULTS

CN and MEST have a remarkable similarity in sex predilection, age distribution, and morphologic attributes of both the epithelial and stromal components and immunohistochemical profile, albeit with variation in individual categories, with higher prevalence of stromal-to-epithelial ratio, prominent ovarian-like stroma, smaller cysts, and stromal luteinisation in MEST, and large cysts, thin septa, and low stromal-to-epithelial ratio in CN. The stromal component in both lesions expresses estrogen and progesterone receptors. Rare and unusual morphologic features, such as endometrioid, cervical, and intestinal differentiation, and luteinised ovarian-like stroma, have been described in MEST. The epithelial element occasionally shows estrogen and progesterone receptors. Rare aggressive behaviour has been reported for both neoplasms.

CONCLUSIONS

Considerable overlap is apparent between the two lesions, which suggests that they may represent opposite ends of the spectrum of the same process. Even though an aggressive behaviour has been reported in very few cases, in general both neoplasms are considered benign and surgical excision is curative.

Malignant mixed epithelial and stromal tumor of the kidney with rhabdoid features: report of a case including immunohistochemical, molecular genetic studies and comparison to morphologically similar renal tumors

Mixed epithelial stromal tumor of the kidney (MEST)/adult cystic nephroma (CN) is a lesion characterized by epithelial lined tubular or cystic structures interspersed within a variably prominent, distinctive spindle-cell stroma. Although typically benign, cases with malignant features have been reported. Herein, we report a MEST/CN with malignant stromal features and rhabdoid differentiation arising in the left kidney of an 84-year-old woman. Histologically, the tumor displayed multiple tubules and variably sized cystic structures lined by benign epithelium with an intervening malignant-appearing spindle-cell stroma. The malignant stroma displayed condensation in the regions surrounding the epithelial component consistent with the ovarian-like stroma typically observed in MEST/CN. In addition, the stromal cells displayed extensive rhabdoid differentiation. Immunohistochemical analysis revealed strong expression of cytokeratin 7, CAM 5.2, AE1/AE3, wide-spectrum keratin, and epithelial membrane antigen by the epithelial component. The stromal component displayed strong immunohistochemical expression of WT-1, CD-99, CD-56, INI1, and estrogen receptor; focal actin positivity; and was negative for desmin, myogenin, and progesterone receptor. Analysis by reverse transcriptase polymerase chain reaction failed to identify the SYT-SSX1 or SYT-SSX2 fusion transcripts characteristic of synovial sarcoma. To our knowledge, this represents the first report in the literature of malignant MEST with rhabdoid features and suggests that this entity should be considered in the diagnosis of renal stromal malignancies with prominent rhabdoid features.

Recently Described and Emphasized Entities of Renal Neoplasms

Context.—Recent advances of molecular biology and cytogenetics of renal cancer have resulted in the new classification of renal neoplasms and a number of subtypes are identified and emphasized. In addition, rare nonepithelial renal neoplasms are identified and characterized. Familiarity with these entities will help make the most accurate diagnosis and guide the treatment and follow-up of patients with renal neoplasm.

Objective.—To review the clinicopathologic entities of renal neoplasms that are recently defined or emphasized. Their clinical, gross, microscopic, and immunohistochemical features, as well as specific cytogenetic or molecular abnormalities, are discussed. Important differential diagnoses of each entity are also briefly discussed.

Data Sources.—Extensive review of published literature and our experience.

Conclusions.—A number of new entities of renal neoplasms or genetically defined renal cell carcinomas have been identified or emphasized because of their unique genetic or molecular changes. Recognition of these entities becomes important as some of them have different biologic behavior and treatment strategies may be different.

Primary synovial sarcoma of the kidney: corroboration with in situ polymerase chain reaction

Synovial sarcoma is a tumor of the soft tissues with a unique chromosomal translocation t(X;18)(p 11.2;q11.2) that can be detected by polymerase chain reaction in tissue homogenates. The case of a 32-year-old woman with a primary synovial sarcoma of the kidney is described, the diagnosis was corroborated by the recently developed method of in situ polymerase chain reaction (IS-PCR). Synovial sarcoma of the kidney may be confused with other spindle cell tumors, for that reason IS-PCR may be useful to confirm the diagnosis in paraffin-embedded material.

Malignant Solitary Fibrous Tumor of the Kidney: Report of a Case and Comprehensive Review of the Literature

Renal solitary fibrous tumors (SFTs) have been reported infrequently. We report a 76-year-old man with a left renal mass that had previously been shown radiographically to be stable, but was now growing. Grossly, the mass measured 12 cm, was poorly circumscribed, and invaded beyond the renal capsule. Approximately 10% of the neoplasm consisted of haphazardly arranged spindle cells admixed with dense collagenous bands, which is typical of benign SFT. However, the remainder of the mass was composed of pleomorphic, spindled sarcoma cells with frequent mitoses and foci of necrosis. Immunohistochemically, we observed CD34 labeling in the benign SFT component with loss of expression in the sarcomatous component, focal labeling for Bcl-2 protein in both areas, and absence of labeling for cytokeratin, renal cell carcinoma marker, S100 protein, CD117, and muscle markers in both areas. To our knowledge, this is the first reported case of malignant renal SFT, likely representing transformation from a histologically documented benign SFT component.

Malignant intraosseous peripheral nerve sheath tumour of the proximal femur: a case report

We report a rare case of an intraosseous malignant peripheral nerve sheath tumour of the femoral head and neck. The tumour presented as a well-defined radiolucent lesion on plain radiography. Computed tomography showed aggressive destruction of the bone with no involvement of the adjacent soft tissues. Magnetic resonance imaging revealed an isointense signal intensity on T1-weighted images, hyperintensity on T2-weighted images, and non-homogeneously increased signal intensity after administration of contrast media. The final diagnosis was based on pathohistologic analyses due to the non-specific nature of the lesion.

Renal cystic diseases: a review

This review aims to assist in the categorization of inherited, developmental, and acquired cystic disease of the kidney as well as to provide a pertinent, up-to-date bibliography. The conditions included are autosomal-dominant polycystic kidney disease, autosomal-recessive polycystic kidney disease, unilateral renal cystic disease (localized cystic disease), renal simple cysts, multicystic dysplastic kidney, pluricystic kidney of the multiple malformation syndromes, juvenile nephronophthisis and medullary cystic disease, medullary sponge kidney, primary glomerulocystic kidney disease, and glomerulocystic kidney associated with several systemic disorders mainly of genetic or chromosomal etiology, cystic kidney in tuberous sclerosis, and in von Hippel-Lindau syndrome, cystic nephroma, cystic variant of congenital mesoblastic nephroma, mixed epithelial stromal tumor of the kidney, renal lymphangioma, pyelocalyceal cyst, peripylic cyst and perinephric pseudocyst, acquired renal cystic disease of long-term dialysis, and cystic renal cell carcinoma and sarcoma. Whereas the gross and histologic appearance of some of these conditions may be diagnostic, clinical and sometimes molecular studies may be necessary to define other types.

Primary renal synovial sarcoma confirmed by cytogenetic analysis: a lesion distinct from sarcomatoid renal cell carcinoma

Primary synovial sarcoma rarely originates in the renal parenchyma. When this occurs, origin of this unusual tumor type has been the subject of debate in the literature, with a suggestion that previously reported cases may be more correctly described as renal cell carcinoma with sarcomatoid dedifferentiation. Synovial sarcoma and sarcomatoid renal cell carcinoma may be indistinguishable on pure histologic and immunohistochemical grounds, but these tumors contain distinctly different sets of chromosomal abnormalities. Most previous cases of primary renal synovial sarcoma were confirmed by molecular biology techniques, which detected the SYT-SSX gene fusion transcript typical of this tumor, but no details of the other chromosomal anomalies have been published. We report a case of primary renal synovial sarcoma confirmed by standard cytogenetic analysis, showing the characteristic t(X; 18)(p11.2:q11.2) translocation and other chromosomal aberrations that are typical of synovial sarcoma as opposed to sarcomatoid renal cell carcinoma.

Tubulocystic Carcinoma, Mucinous Tubular and Spindle Cell Carcinoma, and Other Recently Described Rare Renal Tumors

In the past 10 years, several new renal tumors have been identified. Some have been reviewed in this article, and others have been reviewed elsewhere in this issue. Most have been included in the 2004 edition of the WHO classification of tumors of the urinary system and male genital organs. Tubulocystic carcinoma needs to be studied and characterized more fully.

[Mixed epithelial and stromal tumor of the kidney]

We describe a case of mixed epithelial and stromal tumor of the kidney. The tumor was identified in a 63 years old woman and retroperitoneoscopically resected. Immunohistochemistry, electron microscopy and fluorescence in situ hybridization were performed. Grossly, the tumor was well-circumscribed with a diameter of 8 cm and consisted of solid and cystic components. Microscopically, the spindle cell component ranged in appearance from scar-like fibrous tissue to leiomyoma-like fascicles. Epithelial elements were composed of tubules with variable lining. The tubules were focally transformed into large cysts. Estrogen and progesteron receptors were detected in the nuclei of the spindle cells. Electron microscopy confirmed a smooth-muscle differentiation of the spindle cells. Previously, such tumors were published as adult mesoblastic nephroma or cystic hamartoma of the renal pelvis. Its predominance in females with a history of long-term estrogen replacement or the history of long-term sex-steroid use in a male patient, combined with the expression of estrogen und progesteron receptors in the spindle cells suggest that hormonal influence is relevant for the development of these tumors.

Primary Intrathoracic Synovial Sarcoma

Synovial sarcoma (SS), an aggressive neoplasm accounting for up to 14% of soft tissue sarcomas, was recently recognized as a primary tumor in the lung and pleura. SS is characterized by the chromosomal translocation t(X;18)(SYT-SSX) found in more than 95% of the tumors. We report a cooperative study from the French Sarcoma Group and the Mesopath Group on 40 t(X;18)(SYT-SSX)-positive primary intrathoracic SS. There were 22 males and 18 females, whose age ranged from 16 to 79 years (median, 47 years). Neoplasms were mostly circumscribed and of large size (median, 7.5 cm; range, 2-16 cm). Thirty-nine tumors were monophasic SS, including 24 (60%) monophasic fibrous and 15 (37.5%) poorly differentiated cases, and one lesion was a biphasic SS. A larger proportion of poorly differentiated tumors were observed among intrathoracic SS as compared with soft tissue SS. Immunohistochemically, 90% of the cases reacted with at least one epithelial marker. CD34 was focally expressed in 3 cases. SYT-SSX1 fusion transcripts were detected in 22 cases (56.4%) and SYT-SSX2 fusion transcripts in 17 cases. Median and 5-year disease-specific survival in 33 patients was 50 months and 31.6%. Median and 5-year disease-free survival was 24 months and 20.9%. Patient sex, age, tumor size, histologic subtype, grade, and SYS-SSX fusion type had no significant impact on outcome. In conclusion, intrathoracic SS are rare but aggressive tumors with poor prognosis. In this unusual location, the detection of SYT-SSX fusion transcripts is a valuable diagnostic adjunct.