Anaplastic Wilms' tumor and other clinically aggressive childhood renal neoplasms: ultrastructural and immunocytochemical features

Clear cell sarcoma of the kidney: patients' characteristics and improved outcome in developing countries

BACKGROUND

Clear cell sarcoma of the kidney (CCSK) is a rare and aggressive tumor accounting for 5% of pediatric renal tumors with an incidence of 20 patients per year in the USA. It is bone metastasizing with poor prognosis. Our aim was to show characteristics of patients in relation to improved outcome in one of the developing countries.

PROCEDURE

We included all patients diagnosed as CCSK in the period between July 2007 and March 2012 at Children's Cancer Hospital, Egypt. Patients' demographics, clinical presentation, pathology, and management were reviewed. Follow up was continued until April 2013.

RESULTS

Twenty-five patients were identified in the defined time interval, accounting for 7% all renal tumors diagnosed at the hospital. Mean age was 36 months. Abdominal swelling and hematuria were the most common presentations. Stages I, II, III, IV, and V represented 9 (36%), 3 (12%), 8 (32%), 3 (12%), and 2 (8%), respectively. Twenty-four patients had radical nephrectomy either upfront or after neo-adjuvant chemotherapy. Surgery was followed by adjuvant chemotherapy. Abdominal radiotherapy was given for local stages II and III. Twenty-two patients reached complete remission, while one patient had stationary disease and two patients died due to progression and relapse. Overall survival was 88.5% and event-free survival was 87.8% at 45 months.

CONCLUSION

Although previous studies indicate poor prognosis of CCSK, our experience shows that those patients can be treated using extensive chemotherapy combined with proper local control.

The spectrum of pediatric tumors in infancy, childhood, and adolescence: a comprehensive review with emphasis on special techniques in diagnosis

The spectrum of pediatric tumors varies considerably, from those derived from blastemal cells in various organ systems to proliferations of soft tissue supporting cells to hamartomatous processes that mimic malignant tumors. Small round cell tumors are often undifferentiated or poorly differentiated, making it difficult sometimes to provide a definitive diagnosis. Both benign and malignant tumors require a coordinated method for diagnosis, and need a comprehensive evaluation to provide the most appropriate diagnosis for designing therapy and predicting prognosis. Pediatric tumors require the integration of routine histopathologic examination with histochemical, immunocytochemical, ultrastructural, cytogenetic, and diagnostic molecular pathology techniques. This review provides updated guidelines with respect to the application of these special techniques in this rapidly evolving diagnostic arena.

Translocation (10;17)(q22;p13): a recurring translocation in clear cell sarcoma of kidney

A clear cell sarcoma from the kidney of a 12-month-old male child manifested a balanced translocation, t(10;17)(q22;p13). This is the second report of this cytogenetic abnormality in renal clear cell sarcoma.

Renal cell carcinoma with rhabdoid features

Neoplasms with rhabdoid features have been reported at many anatomic sites. In the kidney, rhabdoid tumors are typically found in children, whereas only rare examples have been reported in adults. Little is known of renal cell carcinomas (RCCs) that exhibit rhabdoid features. The objective of this study was to determine the incidence of RCC with rhabdoid attributes and characterize the histologic, immunophenotypic, and ultrastructural features by retrospective analysis of 480 consecutively identified cases of RCC in radical nephrectomy specimens. Immunohistochemical evaluation was performed in cases with rhabdoid foci using a panel of antibodies to pancytokeratin (pan-CK), CK7, CK20, epithelial membrane antigen (EMA), S-100 protein, desmin, vimentin, neuron-specific enolase (NSE), muscle-specific actin (MSA), smooth muscle actin (SMA), human melanoma, black-45 (HMB-45), and glial fibrillary acidic protein (GFAP). Electron microscopy was also performed in selected cases. The presence and extent of rhabdoid foci in relation to pathologic stage and grade were assessed. Twenty-three of 480 cases of RCC (4.7%) exhibited rhabdoid features. The 23 patients were all adults with a mean age of 61.8 years (age range, 33-84 yrs). Fifteen of the patients were men and eight were women. Histologically, the rhabdoid foci were typified by sheets and clusters of variably cohesive, large epithelioid cells with vesicular and often eccentric nuclei, prominent nucleoli, and large, paranuclear intracytoplasmic hyaline globules (inclusions). The presence of these rhabdoid features was related to high histologic Fuhrman grade of the nonrhabdoid carcinoma component, with an incidence of 0 of 84 grade I cases, eight of 300 grade 2 cases (2.6%), six of 70 grade 3 cases (8.9%), and nine of 26 grade 4 cases (34.6%; p = 3 x 10(-9)). The rhabdoid foci were all high grade. The presence of rhabdoid foci was also found in higher stage carcinomas. A total of 52% (12 of 23) of RCC cases with rhabdoid features exhibited extrarenal extension compared with 28% (24 of 92) of contemporary RCCs without rhabdoid features (p = 0.03). The size of the rhabdoid component ranged from 1 mm to more than 2 cm and comprised 1% to 50% of the renal mass. Immunoreactivity for vimentin (100%), NSE (79%), and panCK (56%) was present in the majority of cases. Substantial percentages of cases were immunopositive for EMA (47%) and S-100 protein (37%), with minimal to no immunohistochemical reactivity for CK7 (5%), SMA (5%), CK20 (0%), desmin (0%), MSA (0%), HMB-45 (0%), and GFAP (O%). A distinctive globular, paranuclear reaction pattern was found for the cytokeratin, EMA, and vimentin immunostains. Ultrastructurally, the rhabdoid cells had paranuclear intermediate filament aggregates or paranuclear condensation of organelles, often associated with peripheral vacuolization. Adult RCCs may harbor a rhabdoid component, and these neoplasms can be regarded as "composite" tumors. Rhabdoid elements are important to identify because of their high-grade nature, and association with high stage. Adult RCC with rhabdoid elements should be distinguished from pure rhabdoid tumors of kidney, in light of their clinicopathologic differences. Rhabdoid differentiation in adult renal cell carcinoma may represent clonal divergence and/ or evolution, and emergence of a particularly aggressive element.

Comparative immunohistochemical analysis of developing kidneys, nephroblastomas and related tumors: considerations on their histogenesis

Immunoperoxidase analysis was performed to evaluate the phenotypic expression of eight renal differentiation antigens in five nephroblastomas, one clear cell sarcoma of the kidney (CCSK), one rhabdoid tumor of the kidney (RTK), and four related tumors. A total of 19 fetal and pediatric kidneys, including two 6th-week mesonephric tissues, were comparatively studied. All the specimens were fixed in formalin and embedded in paraffin. Neural cell adhesion molecule (NCAM), a marker of the nephrogenic zone of the developing kidney, was consistently expressed in the epithelial and blastematous components of nephroblastomas of the common type. The epithelial components also commonly expressed NK1 and Leu 7 (CD57), and the findings may reflect that both were positive in immature proximal tubules directly differentiating from the NCAM-positive immature fetal tubuloglomerular buds. In two cases, the epithelial component was immunoreactive for CD10 and WT1 gene product (WT1-GP). Leu M1, epithelial membrane antigen and CA15-3 were only focally expressed in nephroblastomas. Rhabdomyoblasts in the stroma were positive for WT1-GP. CCSK was featured by the expression of NCAM and CD10. In RTK, focal epithelial differentiation was discerned, with focal positivity of WT1-GP and negativity of NCAM. In congenital mesoblastic nephroma, the stromal spindle cells were strongly immunoreactive for WT1-GP, while WT1-GP was not expressed in solitary multilocular cyst of the kidney. Pancortical nephroblastomatosis was featured by the diffuse subcapsular reappearance of immature metanephric tissue. Nephroblastomas and related conditions thus offer an adequate model for studying human nephrogenesis.

Comparative genomic hybridization analysis of clear cell sarcoma of the kidney

BACKGROUND

Clear cell sarcoma of the kidney (CCSK) is a rare malignant pediatric tumor, distinguished from the Wilms tumor by its characteristic histologic features and a more aggressive clinical behavior with a tendency to metastasize to bone. Genetic studies on CCSK are limited and no consistent findings have been reported.

PROCEDURE

We examined four cases of CCSK for presence of consistent genetic alterations using comparative genomic hybridization (CGH). This is the first report concerning CGH analysis of CCSK.

RESULTS

Three of the tumors showed no chromosome gains or losses. One of the tumors had gains of 1 q and the terminal end of 11 q.

CONCLUSIONS

These results are consistent with previous findings of limited chromosomal changes in CCSK karyotypes. Gain of 1 q in CCSK warrants further investigation. Copy number gains of 1 q have been repeatedly demonstrated in soft tissue and bone sarcomas, as well as other tumors, implying the presence of genes involved in tumor development and/or progression.

Appraisal of the comparative utility of immunohistochemistry and electron microscopy in the diagnosis of childhood round cell tumors

To provide an objective assessment of the comparative utility of fluorescence- and peroxidase-based immunohistochemistry and electron microscopy, an observer blinded study was conducted under realistic study conditions utilizing a large sampling of poorly differentiated pediatric round cell tumors. Working independently, using a single ancillary technique of particular expertise, each of three investigators attempted to render a specific diagnosis with regard to 50 diagnostically challenging tumors. The results were compared against the subsequent "file diagnosis" established by consensus with all relevant information made available. A grading scheme was applied wherein points were awarded based on the accuracy and confidence of diagnosis. A comparative efficiency rating, expressed as a percentage, was formulated by dividing the number of points awarded each technique by the total number of points theoretically available. Electron microscopy proved superior overall, with an efficiency rating of 89%. Immunoperoxidase and immunofluorescence studies yielded efficiency ratings of 71 and 61%, respectively. Used in combination, the techniques achieved an efficiency rating of 95%. Application of these ancillary techniques resulted in a revision of the provisional diagnosis in 11 of 50 cases, and left only two cases without a firm specific diagnosis.

Ultrastructure of cellular congenital mesoblastic nephroma

A detailed ultrastructural description of the cellular variant of congenital mesoblastic nephroma (CMN) is presented and compared to the classical form. Studied were 9 cases of the cellular variant, 6 mixed (cellular/classical) tumors, and 1 classical CMN. The occurrence of a broad selection of ultrastructural features was assessed using a semiquantitative scoring system. The results indicate that cellular CMNs are composed mainly of primitive mesenchymal cells, but also usually contain varying numbers of differentiating fibroblasts and myofibroblasts. This entity thus bears a closer resemblance at the ultrastructural level of organization to infantile fibrosarcoma than to conventional fibrosarcoma. Electron microscopy can be useful in distinguishing this relatively benign entity from the several malignancies with which it is sometimes confused.

Mixed ependymoma-neuroendocrine tumor of the lateral ventricle

A histologically unique glioneuronal neoplasm occupying the lateral ventricle of a child was immunohistochemically and ultrastructurally characterized. Its principal component exhibited the characteristic features of ependymoma, whereas a minor population of neuroendocrine cells, occurring singly and in small clusters, lay scattered throughout the ependymoma component. Yet another unusual finding was the presence of numerous elastic fibers within the extracellular matrix. This tumor is considered to represent a true mixed neoplasm consisting of ependymal and neuroendocrine elements.

Bone metastasizing renal tumor of childhood. A clinicopathological study of eleven cases from the Prague Pediatric Tumor Registry

Eleven patients with bone metastasizing renal tumor of childhood (BMRTCh) who were diagnosed and treated in our departments over a 20-year period were reviewed. The incidence among all malignant renal tumors in children up to 15 years of age in our files was 3.7%. The male to female ratio was 10:1. The morphology had a uniform, predominantly clear cell finely vascularized pattern in all of them. Various previously recognized variations of the classic pattern such as hyalinization, nuclear palisading and cyst formation were observed in some patients. Electron microscopy showed that coarse vacuolization of the tumor seen at the light microscopic level was due to distended extracellular spaces surrounded by tumor cells and their cytoplasmic processes. Immunohistochemistry of the tumor cells revealed positive vimentin in all cases, and focally positive muscle specific actin in one. A prominent feature was fascicles of perivascular spindle cells. They were considered to be tumor cells rather than stromal elements since their morphology was close to the appearance of the polygonal tumor cells. The follow up data were available for ten patients. Four developed bone metastases, three of them died of the disease progression. Another patient died of lymph node dissemination and gastrointestinal bleeding. Six patients survived for a period of 29 months to 14 years following the diagnosis.

Primitive cerebral tumor with rhabdoid features: a case of phenotypic rhabdoid tumor of the central nervous system

The rhabdoid tumor (RT) was first described as an aggressive neoplasm of unknown histogenesis affecting the kidneys of infants and young children, but has since been reported in all ages and in many other primary sites, including the central nervous system. It has been shown, however, that the histologic and cytologic features of RT can be mimicked by many other tumors of known histogenesis. For this and other reasons it remains controversial whether cases of putative extrarenal RT represent the same histogenetic entity as RT of the kidney (RTK), another entity or entities, or merely a diverse collection of unrelated tumors sharing a common morphologic phenotype. The present paper describes a lethal primary cerebral tumor in a 26-month-old Hispanic boy that was composed predominantly of cells exhibiting the "classic" rhabdoid phenotype by light microscopy. Immunocytochemical and ultrastructural studies disclosed features of primitive neuroglial differentiation not seen in RTK. The findings in this case, as well as evidence from other studies, would seem to support the notion that primary RT of the brain may in fact constitute a morphologic and clinicopathologic entity. However, that entity likely represents a distinctive type of neuroglial neoplasm, more closely related to other primitive brain tumors than to RTK.

Spectrum of differentiation in pediatric epithelial tumors of kidney: report of two cases

Two unusual presentations of childhood renal cell epithelial tumors including one whose unique clinical manifestation was polycythemia are described. One was a renal cell carcinoma which was so poorly differentiated that ancillary histopathologic techniques were necessary to arrive at the correct diagnosis. The other case represented the opposite extreme being so well-differentiated as to raise the differential diagnosis of renal cell carcinoma versus renal cell adenoma with blastemal areas. These case studies exemplify the practical role for specialized histopathologic techniques in diagnosing pediatric renal tumors, which may not be feasibly or even accurately categorized into known renal tumor types using routine diagnostic methods.

Brain metastasis from clear cell sarcoma of the kidney--a case report and review of the literature

We describe a 5 year old boy with a 5.5 cm right frontal lobe brain metastasis from primary clear cell sarcoma of the kidney without evidence of tumor-associated edema or contrast enhancement on either computed tomography or magnetic resonance imaging. The metastasis regressed but did not disappear with chemotherapy and dexamethasone, and the residual tumor was removed surgically. On histological examination the majority of the tumor was composed of mature connective tissue with a rim of typical renal clear cell sarcoma cells at the brain-tumor interface. The avascular and desmoplastic nature of the metastasis may explain the unusual radiographic features. Brain metastases from this tumor have only infrequently been reported; therefore a brief review of this rare tumor is provided.

Clear cell sarcoma of kidney. Two cases in adults

BACKGROUND

Clear cell sarcoma of kidney (CCSK) is an aggressive renal tumor occurring most frequently in the second and third years of life. Although it has been reported in the literature in patients as old as 21 years of age, there has been no report focusing on adults with CCSK. The authors describe two cases of CCSK in men and the findings at autopsy.

METHODS AND RESULTS

Histologically, the renal tumors consisted of a homogeneous proliferation of polygonal or short spindle cells with faintly eosinophilic cytoplasm supported by a network of small vessels. Ultrastructurally, clusters of tumor cells were surrounded by collagen bundles. Elongated cytoplasmic processes, dilated rough endoplasmic reticulum, and intermediate filaments in the cytoplasm; primitive desmosome-like junctional structures; and incomplete basal lamina were observed. Immunohistochemically, tumor cells had positive results only for vimentin. Cytokeratins, epithelial membrane antigen, desmin, myoglobin, S-100 protein, neuron-specific enolase, and chromogranin A were not detected in the tumor cells. Both patients died within 2 years of onset of disease, and autopsy showed widespread metastases, especially in the soft tissue and bone.

CONCLUSIONS

Morphologic findings and an aggressive clinical course with metastasis to the bone and soft tissue are supportive of the diagnosis of CCSK in these patients.

Clear cell sarcoma of the kidney in a 4-month-old infant: a case report

A case of clear cell sarcoma of the kidney is described in a 4-month-old male infant. The tumor had a typical histological pattern, consisting of sheets of tumor cells possessing "empty" nuclei set within a delicate capillary network. There was extensive necrosis and tumor cell cytoplasm contained vimentin. This tumor occurs only rarely in infants less than six months of age. The different renal neoplasms of childhood have diverse prognoses and demand specific therapy so that accurate diagnosis is mandatory. The present case illustrates that clear cell sarcoma, a highly malignant neoplasm, must be considered in the differential diagnosis of a renal mass occurring in this age group.

Malignant rhabdoid tumour of the liver. A case report

A case of primary malignant rhabdoid tumour of the liver occurring in a 5-month-old girl is reported. Histologically the neoplasm presented the 'typical' features as described in malignant rhabdoid tumour arising in the kidney. In addition, some areas of the tumour showed a 'pseudoglandular' growth pattern. Immunohistochemistry revealed the neoplastic cells to be intensively positive for vimentin and for cytokeratin 19. Variable immunoreactivity for cytokeratin polypeptides 7, 8 and 19 was also detected. On electronmicroscopy the neoplastic cells contained bundles of intermediate filaments, tonofilaments and intercellular junctions. These findings are suggestive of a primitive epithelial differentiation.

Filamentous inclusions of unusual composition and architecture in a metastatic tumor showing myoepithelial differentiation

A hyaline/eosinophilic cytoplasmic inclusion is described in a metastatic tumor occurring in the omentum and bowel of a 32-year-old white woman. The tumor was essentially of round cell type; was positive for cytokeratin, actin, and S-100 protein by immunohistochemistry; and showed desmosomes (maculae adherentes), tonofibrils, modestly developed myofilaments with focal densities, and a basal lamina by electron microscopy. It was therefore interpreted as showing myoepithelial differentiation. Nearly all cells possessed a large, rounded cytoplasmic inclusion that was architecturally unusual, consisting of intermediate filaments intermingled with lattices of fine filaments. The inclusions exhibited an additionally unusual immunohistochemical staining for both cytokeratin and actin. A comparison with cases described in the literature is made.

Rhabdoid tumors of soft tissues: a clinicopathologic study of 26 cases enrolled on the Intergroup Rhabdomyosarcoma Study

Twenty-six cases of malignant soft tissue tumors with features similar to renal rhabdoid tumors were identified among approximately 3,000 childhood sarcomas entered on Intergroup Rhabdomyosarcoma Studies I-III. The tumors consisted of polygonal cells with vesicular nuclei and prominent nucleoli and cytoplasmic intermediate filament inclusions as identified by electron microscopy and immunohistochemistry. The growth pattern was predominantly solid or solid-trabecular. Immunohistochemistry showed vimentin, wide spectrum keratin, and epithelial membrane antigen to be the most consistent antigenic phenotypes. Eleven patients were infants less than 1 year of age. The tumors affected predominantly soft tissues of proximal extremities, trunk, and retroperitoneum/pelvis/abdomen. Nineteen patients died within 1 to 82 months (median, 6 months) from the start of treatment. Five patients have survived the disease for 2 to 13 years. When compared with the survival analysis of 991 Intergroup Rhabdomyosarcoma Study II patients, it was obvious that this group of tumors fares very poorly (P less than .001). The tumor belongs to the group of soft tissue neoplasms showing mesenchymal and subtle epithelial differentiation, similar to epithelioid sarcoma. Because of its identifiable histology, site and age distribution, and poor outcome, it warrants a status as an independent entity.

Primitive pelvic sarcoma resembling clear cell sarcoma of kidney

Clear cell sarcoma of kidney (CCSK) is an aggressive childhood renal tumor of unknown histogenesis that has not been reported to occur outside the kidney. The article describes an extrarenal neoplasm arising in the pelvic soft tissues of a 13-year-old boy that was composed predominantly of uniform mesenchymal cells with optically clear cytoplasm supported by an arborizing network of small blood vessels, which was indistinguishable in appearance from CCSK. The electron microscopic findings, although nonspecific, were essentially identical to those of CCSK, with tumor cells displaying fine chromatin, electron-lucent cytoplasm, and intercellular collagen but no evidence of tissue-specific differentiation. Immunocytochemical studies showed positivity for vimentin but negative results for desmin, myoglobin, cytokeratin, epithelial membrane antigen, S-100 protein, neuron-specific enolase and factor VIII-related antigen. Tumor cells were also nonreactive with Ulex lectin. This unusual pelvic tumor and CCSK may both derive from primitive mesenchymal cells and may represent phenotypic but not necessarily histogenetic analogs.

Nondifferentiated-type small cell sarcoma of kidney in a young woman

A case of rapidly fatal small cell sarcoma of kidney in a young woman is described. Histologic, immunohistochemical, and ultrastructural studies demonstrated some features not reported previously in the literature, such as the arrangement of vimentin intermediate filaments in small irregular masses and the presence of various types of cytoplasmic projections. These findings, together with the observation of rare neoplastic elements with immunophenotypic and subcellular aspects of histiocytic and myofibroblastic differentiation, suggest that this tumor should be included in a group of small cell sarcomas of kidney lacking features of differentiation and should be considered a new variant occurring in adulthood.