Round Cell Tumors Of Childhood Research Articles

Selective Immunoreactivity for WT1 Carboxy-Terminus Distinguishes Desmoplastic Small Round Cell Tumor From its Histologic Mimics.

Desmoplastic small round cell tumor (DSRCT) is an aggressive pediatric round cell sarcoma containing a characteristic EWSR1-WT1 gene fusion. In the absence of genetic data, distinguishing DSRCT from other small round cell tumors of childhood can be problematic due to overlapping histologic and immunohistochemical features. We studied the utility of immunohistochemistry with antibodies targeting both the amino-terminal and carboxy-terminal regions of the Wilms tumor-1 (WT1) protein in differentiating these groups of tumors. The study cohort included 33 cases of genetically confirmed pediatric round cell tumors (10 DSRCTs, 12 Wilms tumors, 10 Ewing sarcomas, and 1 CIC-rearranged sarcoma). Immunoreactivities and immunolocalization of both the WT1 amino-terminus and carboxy-terminus were scored and documented. All DSRCTs displayed selective reactivity for only the WT1 carboxy-terminus (10/10), while dual immunoreactivity for both the WT1 carboxy-terminus (12/12) and amino-terminus antibodies (12/12) were characteristic of Wilms tumors. CIC-rearranged sarcoma showed variable WT1 nuclear immunopositivity (1/1, 1/1) and Ewing sarcomas were consistently WT1-negative for both the WT1 amino-terminus (0/10) and carboxy-terminus (0/10). Dual WT1 amino-terminus and carboxy-terminus immunohistochemistry remains a helpful diagnostic tool in discriminating intraabdominal small round cell tumors, which serves as an adjunct to the genetic information in preventing misdiagnosis.

PAX Immunoreactivity in Poorly Differentiated Small Round Cell Tumors of Childhood

Paired box (PAX) gene antibodies have made it into the mainstream of tumor diagnosis in the recent years. We report the immunoreactivity expression patterns of three PAX genes (PAX2, PAX5 and PAX8) in poorly differentiated small round cell tumors of childhood for possible useful diagnostic applications. We collected and analyzed 123 cases of poorly differentiated small round cell tumors of childhood for their PAX immunoexpression patterns. The results indicated that PAX2 was strongly positive in all alveolar rhabdomyosarcomas and in two-thirds of the kidney clear cell sarcomas, and displayed variable expression in one-half of the embryonal rhabdomyosarcomas. PAX8 immunoexpression was noticed in five and three cases of alveolar rhabdomyosarcomas and embryonal rhabdomyosarcomas, respectively. About one-third of malignant rhabdoid tumors were PAX2-positive and PAX8-positive. All of the Ewing sarcoma and neuroblastoma cases stained negative with all three PAX stains.

Small Blue Round Cell Tumor

Small blue round cell tumors of childhood rarely present in the foot or ankle. The following is a case presentation of an 18-year-old male with a large soft-tissue mass of the foot with associated lung metastasis. A definitive diagnosis could not be fully made, even with immunohistochemical and genetic testing. Diagnosis favored poorly differentiated synovial sarcoma.

Abdominal undifferentiated small round cell tumor with unique translocation (X;19)(q13;q13.3)

We describe a male with a large abdominal mass, most likely originating from the liver, with capsule rupture and tumor dissemination into the abdominal cavity. Adherence of the tumor to the diaphragm and lower right colon also were noted. A comprehensive evaluation of the mass revealed no tumor-defining histopathologic, immunocytochemical, ultrastructural, cytogenetic, or translocation features. The malignant tumor was found to have a novel translocation (X;19)(q13;13.3), which has not been reported in small round cell tumors of childhood or adults. The final diagnosis rendered was an undifferentiated small round cell tumor of uncertain cell of origin.

Metastatic Neuroblastoma Involving The Distal Third Of The Humerus

Neuroblastoma is predominantly a tumor of early childhood with two thirds of cases presenting in children younger than 5 years. Neuroblastoma originates in adrenal medulla or the paraspinal sites where sympathetic nervous tissue is present. The most common symptoms are due to a tumor mass or to bone pain from metastases. There is involvement of bone marrow in 70% of cases and involvement of bone in 56% of cases. CASE REPORT 3 years old child presented in hospital with swelling(19 16 cms) in the left arm of three months duration (Fig.1). Figure 1 Figure 1: Metastatic Neuroblastoma involving left distal humerus. Swelling started after sustaining trauma of left humerus which was managed by local practitioner fifteen days prior to presentation in hospital. Swelling increased tremendously in size. There was no history of fever and pain. Swelling was fusiform in shape and overlying skin was shiny and erythematous with prominent veins. Temperature over the swelling was slightly raised with mild tenderness. The swelling was hard in consistency, overlying skin was free but muscles were adhered and swelling was immobile. Regional lymph nodes were not palpable and distal neurovascular status was normal. Radiographs revealed diffuse destruction of the distal humeral shaft and metaphyseal region (Fig.2). Figure 2 Figure 2: showing destruction of distal humeral shaft and metaphyseal region. The elbow joint was free and there was diffuse increase in soft tissue shadow. Ultrasonogaphy revealed a mass in suprarenal area, which was confirmed on CT scan as primary neuroblastoma. FNAC and TISSUE biopsy confirmed the diagnosis. DISCUSSION Metastatic involvement of bones takes place in 56% cases of Metastatic Neuroblastoma Involving The Distal Third Of The Humerus 2 of 3 neuroblastoma 4 . Children of any age with localized neuroblastoma and infants younger than 1 year with advanced disease and favourable disease characteristics have a high likelihood of long-term, disease-free survival. Older children with advanced-stage disease, however, have a significantly decreased chance for cure despite intensive therapy 2 . Aggressive multiagent chemotherapy has even resulted in a 2-year survival rate of approximately 20% in older children with stage IV neuroblastoma 1 . Children with neuroblastoma rarely present with paraneoplastic neurologic findings. Some neuroblastomas cannot be differentiated from other small round cell tumors of childhood, such as lymphomas, primitive neuroectodermal tumor, and rhabdomyosarcoma by conventional light microscopy 3 . The parents of the patient were told about the poor prognosis and left shoulder disarticulation was done and the patient was referred to surgical oncology department for further management of the tumour CORRESPONDENCE TO Iftikhar H wani PG Hostel Boys Govt. Medical College Jammu Room No.215B Bakshi Nager Jammu, J & K, INDIA. Email drihwani@yahoo.co.in phone no. +91-9469212594.

A Comparative Immunohistochemical Analysis of Small Round Cell Tumors of Childhood: Utility of Peripherin and α-internexin as Markers for Neuroblastomas

Immunohistochemical study of neuroblastomas, Ewing sarcomas, rhabdomyosarcomas, and Wilms tumors demonstrate specific expression of peripherin and alpha-internexin in 20/22 and 6/22 cases of neuroblastomas, respectively. Microtubule-associated protein 1B (MAP 1B) was strongly and diffusely expressed in all 22 cases of neuroblastomas, but was also focally or multifocally expressed in 9/12 rhabdomyosarcomas and also in the blastema and stroma of 8/11 Wilms tumors. All rhabdomyosarcomas strongly and diffusely express nestin, but this marker was also expressed, multifocally, in 15/22 neuroblastomas and also in the blastema and stroma of all 11 Wilms tumors. NeuN, a neuron-specific nuclear protein, was expressed focally in 1 case of neuroblastoma and diffusely in 2 other cases (3/22). Surprisingly, it was also focally expressed in 2/12 rhabdomyosarcomas. In contrast, all 7 cases of Ewing sarcoma were negative for peripherin, MAP 1B, alpha-internexin, NeuN, and nestin. Thirteen neuroblastomas were also immunostained for neurofilaments, tyrosinase, and anaplastic lymphoma kinase 1 (ALK 1), and were found to be negative for these markers. Our results confirm that peripherin and alpha-internexin are neuroblastoma markers useful for the differential diagnostic work-up of small round cell tumors of childhood. Strong diffuse immunoreactivity for MAP 1B favors a diagnosis of neuroblastoma, whereas strong diffuse immunoreactivity for nestin favors a diagnosis of rhabdomyosarcoma.

Difficulties in diagnosing small round cell tumours of childhood from fine needle aspiration cytology samples

There are four basic reasons for the difficulties in diagnosing small round cell tumours (SRCT) in childhood from fine needle aspiration cytology (FNAC) samples. First, SRCTs are rare and it is difficult for cytopathologists to obtain enough experience for rendering reliable diagnoses. Second, SRCTs are morphologically very similar. Third, many SRCTs do not have specific antigens which could be demonstrated with immunocytochemistry (ICC) or they lose them when poorly differentiated. In addition, cross reactivity exists between some SRCTs. Unstandardized performance of ICC also contributes to the difficulties due to unreliable results. Fourth, suboptimal FNAC samples add additional pitfalls. The latter may be due to partly degenerate samples or to unrepresentative ones in cases where a SRCT is a heterologous component of another nosological entity. Lymphoma, neuroblastoma, nephroblastoma, Ewing's tumour/primitive neuroendocrine tumours and rhabdomyosarcoma are discussed in detail, while other less common SRCTs are mentioned as differential diagnoses when appropriate. The use of cytogenetic and molecular techniques for differentiating between certain SRCTs is helpful in some doubtful cases. However, there are still problems in the use of these techniques, especially their cost which may delay their being introduced in every cytopathology laboratory.

Acute megakaryoblastic leukemia mimicking small round cell tumor with novel t(1;5)(q21;p13). Case report

Acute megakaryoblastic leukemia is a relatively rare form of acute leukemia that has heterogeneous blast morphology and karyotypic abnormalities. An 8-month-old boy with a retroperitoneal mass was diagnosed as having acute megakaryoblastic leukemia that initially presented as small round cell tumor of childhood. Bone marrow aspiration showed syncytial groups of atypical medium sized cells with scant cytoplasm and fine nuclear chromatin. Retroperitoneal mass biopsy showed several lymph nodes with cohesive clusters of neoplastic cells that demonstrated expression of Factor VIII. Flow cytometric analysis of the second bone marrow aspiration showed CD 61 positivity. Karyotypic analysis of bone marrow cells showed a novel translocation, (1;5)(q21;p13).

Diagnostic role of fine needle aspiration cytology in Wilms′ tumour

A ten year retrospective study of 34 cases of Wilms' tumour in children is presented with 24 cases (70.5%) in the age group 0-5 years and a mean age of 4 years. A male: female ratio of 4.7:1 was seen. All the children presented with lump in abdomen, constitutional symptoms in addition were observed in 6 cases. Bilateral tumour was seen in 2 (5.8%) cases. A histocytomorphological correlation with regards to the differential diagnosis of small round cell tumours of childhood in abdominal cavity is discussed. The differential diagnosis of Wilms' tumour includes malignant round cell tumours such as neuroblastoma, non-Hodgkins lymphoma, rhabdomyosarcoma and other pediatric renal tumours such as mesoblastic nephroma, cystic nephroma, rhabdoid tumour and clear cell sarcoma. In cases with high clinical suspicion of Wilms' tumour, where preoperative chemotherapy and radiotherapy are indicated, fine needle aspiration cytology (FNAC) can act as a reliable diagnostic tool to complement the clinical diagnosis.

ALK-Positive Anaplastic Large Cell Lymphoma With Primary Bone Involvement in Children

We describe the clinical, radiologic, and pathologic features of primary bone anaplastic large cell lymphoma (ALCL) in 3 boys. Radiologic imaging showed lytic lesions involving sacrum, femur, or rib. Bone was the only site of disease in 2 cases; an associated partial lymph node was involved in case 3. Differential diagnoses included osteomyelitis and small round cell tumors of childhood, particularly Ewing sarcoma. Preoperatively, ALCL was not a diagnostic consideration in any case. Two cases showed classic large pleomorphic cells; 1 showed a composite pattern with a distinct small cell component and the more typical large cell type. Neoplastic cells in all cases showed strong CD30 and anaplastic lymphoma kinase expression with relatively weak epithelial membrane antigen positivity. Cytotoxic granule protein was expressed in 2 cases. All cases showed unusually strong expression of neuron-specific enolase (NSE). Two patients were disease-free at last follow-up (15 months and 11 years); 1 patient died of disseminated disease within a year of diagnosis. ALCL should be considered a diagnostic possibility when evaluating neoplastic bone lesions in children. Although expression of NSE in ALCL has not been emphasized in the literature, it is worth noting because it may pose a diagnostic pitfall.

Desmoplastic round cell tumor of childhood: Can cytology with immunocytochemistry serve as an alternative for tissue diagnosis?

There are limited reports on the cytology of desmoplastic small round cell tumors (DSRCT). Fine needle aspiration biopsy (FNAB) findings in seven aspirates from four cases of histologically and immunohistochemically confirmed cases were analyzed with the main intention of ascertaining if cytological diagnosis of DSRCT is possible. Also assessed were the immunocytochemistry(ICC) findings in these cases. The basic cytological impression was that of a cohesive small round cell tumor. Nuclei showed granular chromatin with grooves, nuclear molding and inconspicuous nucleoli. Stromal fragments were noted in all four cases. In two cases, awareness of cytological features in the appropriate clinical context led to a suggestion of the diagnosis of DSRCT on cytology itself. ICC on destained smears showed positivity for cytokeratin, epithelial membrane antigen (EMA), desmin and WT-1 in two cases. In conclusion, given the right clinical setting, a cytological diagnosis of DSRCT is plausible and in conjunction with ICC may help in documenting the polyphenotypic nature and thereby confirming the diagnosis.

Juvenile Granulosa Cell Tumor of the Testis: A Case Presenting as a Small Round Cell Tumor of Childhood

Juvenile Granulosa Cell Tumor of the Testis: A Case Presenting as a Small Round Cell Tumor of Childhood

Juvenile Granulosa Cell Tumor of the Testis: A Case Presenting as a Small Round Cell Tumor of Childhood

We describe the case of a testicular juvenile granulosa cell tumor (JGCT) in a 4-year-old boy. The highly undifferentiated appearance and robust mitotic activity of the neoplasm led to an initial impression of an aggressive, small round cell tumor of childhood. Immunocytochemical and ultrastructural studies excluded the usual members of that group, and led to the correct diagnosis. To our knowledge, this is the oldest reported patient to present with this tumor in the testis, and the first with clinical evidence of hormonal activity. The benign behavior of testicular JGCT mandates that it be distinguished from other, much more aggressive, neoplasms which it may resemble.

Characterization of the malignant melanoma of soft-parts cell line GG-62 by expression analysis using DNA microarrays.

GG-62 is a cell line previously thought to be derived from an atypical Ewing tumor (ET). Reverse-transcriptase polymerase chain reaction revealed an in-frame fusion between the Ewing sarcoma gene ( EWS) codon 325 and the activating transcription factor 1 gene ( ATF1) codon 65 which permits the production of chimeric EWS-ATF1 oncoproteins. We also identified the genomic breakpoint resulting from a reciprocal t(12;22)(q13;q12), which is the hallmark of malignant melanoma of soft parts (MMSP). We applied Affymetrix human cancer G110 arrays to compare the gene expression patterns of GG-62 and other cell lines derived from small blue round cell tumors of childhood. Hierarchical clustering of 463 differentially expressed genes distinguished GG-62 from the ETs, as well as the neuroblastomas, and revealed a cluster of 36 upregulated genes. Several of these genes are involved in signal transduction pathways that may be critical for maintaining cell transformation; some examples are avian erythroblastic leukemia viral oncogene homolog 3 ( ERBB3), neuregulin 1 ( NRG1), fibroblast growth factor 9 ( FGF9), and fibroblast growth factor receptor-1 ( FGFR1). Furthermore, genes near the chromosome-12q13 breakpoint exhibited increased expression of GG-62 including ERBB3, NR4A1 (nuclear receptor subfamily 4, group A, member 1), cyclin-dependent kinase 2 ( CDK2), and alpha 5 integrin ( ITGA5). Altogether our findings demonstrate the MMSP derivation of GG-62 and may shed light on the mechanisms of tumorigenesis in this rare disease.

Defining small round cell tumors of childhood: when is a rose really a rose.

Defining small round cell tumors of childhood: when is a rose really a rose.

Primitive Neuroectodermal Tumors of the Biliary and Gastrointestinal Tracts: Clinicopathologic and Molecular Diagnostic Study of Two Cases

Primitive neuroectodermal tumor (PNET) is a prototypic malignant small round cell tumor of childhood that is characterized in most cases by t(11;22) resulting in an EWS-FLI1 gene fusion. Once thought to be uncommon, PNET now accounts for almost 20% of malignant soft tissue tumors in children. Increased recognition of PNET is partly due to advances in immunohistochemistry and molecular diagnostics, which have led to the identification of the tumor in non-classical sites. We report the clinical, histologic, immunohistochemical, and molecular findings of two visceral PNETs of the digestive system--one involving the small intestine and the other involving the hepatic duct. Histologically, each tumor was composed of malignant small cells growing in sheets, nests, and lobules; the tumor cells of both cases showed characteristic immunoreactivity for vimentin and O13 (CD99). Reverse transcription-polymerase chain reaction (RT-PCR) analysis for t(11;22) using nested primers was performed with RNA extracted from paraffin-embedded, formalin-fixed tissue and demonstrated an EWS exon 7 to FLI1 exon 5 fusion in both cases, confirmed by Southern blot hybridization and DNA sequence analysis. These results illustrate the expanded clinicopathologic profile of PNET, and demonstrate that visceral PNETs, despite their unusual sites of presentation, maintain the characteristic immunohistochemical and genetic features of PNETs at more conventional sites.

Myogenin is a Specific Marker for Rhabdomyosarcoma: An Immunohistochemical Study in Paraffin-Embedded Tissues

Myogenin belongs to a group of myogenic regulatory proteins whose expression determines commitment and differentiation of primitive mesenchymal cells into skeletal muscle. The expression of myogenin has been demonstrated to be extremely specific for rhabdomyoblastic differentiation, which makes it a useful marker in the differential diagnosis of rhabdomyosarcomas (RMS) from other malignant small round cell tumors of childhood. Commercially available antibodies capable of detecting myogenin in routinely processed formalin-fixed paraffin-embedded (FFPE) tissue are now available. In this study, we evaluated myogenin expression using the monoclonal myf-4 antibody (Novocastra Labs) on FFPE in a large number of pediatric tumors in order to define the clinical utility of this marker. A total of 119 tumors were studied. These included 48 alveolar RMS (ARMS), 20 embryonal RMS (ERMS), one spindle cell RMS, 16 Ewing's sarcomas (ES), six nephroblastomas, two ectomesenchymomas, seven precursor hematopoietic neoplasms, five olfactory neuroblastomas, three neuroblastomas, six desmoplastic small round cell tumors, and five rhabdoid tumors. Distinct nuclear staining for myogenin was noted in all 69 RMS. Notably, the number of positive tumor cells differed between the ARMS and ERMS. In ARMS, the majority of tumor cells (75 to 100%) were positive, in contrast to ERMS, in which the positivity ranged from rare + to 25% in all but three tumors. Additionally, myogenin positivity was seen in two of two ectomesenchymomas and in two nephroblastomas with myogenous differentiation. All other tumors were clearly negative. Our results indicate that staining for myogenin is an extremely reliable and specific marker for rhabdomyoblastic differentiation. It gives consistent and easily interpretable results in routinely fixed tissues.

WT1 staining reliably differentiates desmoplastic small round cell tumor from Ewing sarcoma/primitive neuroectodermal tumor. An immunohistochemical and molecular diagnostic study.

Differentiating desmoplastic small round cell tumor (DSRCT) from another similar small round cell tumor of childhood, the Ewing sarcoma/primitive neuroectodermal tumor (EWS/PNET), can be difficult because morphologic and immunohistochemical features overlap. We studied the predictive value of immunohistochemistry with an antibody to the C-terminal region of the Wilms tumor (WT1) protein for differentiating DSRCT from EWS/PNET in 24 malignant small round cell tumors that had been previously diagnosed as DSRCT or EWS/PNET by standard methods. We performed reverse transcriptase-polymerase chain reaction (RT-PCR) analysis in cases with available tissue as a confirmatory measure: 6 of 13 DSRCTs were informative by RT-PCR, and 6 of 6 showed an EWS-WT1 fusion; all 13 DSRCTs showed strong, definitive nuclear staining with the WT1 antibody. All 11 EWS/PNETs were WT1 antibody negative; 7 of 11 cases classified as EWS/PNET were informative by RT-PCR, and 7 of 7 showed an EWS-FLI-1 fusion. For cases in which the morphologic and immunohistochemical features are consistent with a diagnosis of DSRCT, WT1 antibody staining predicts the EWS-WT1 translocation with high sensitivity and specificity and is, therefore, useful for differentiating DSRCT from EWS/PNET when genetic information is unavailable.

Approach to Small Round Cell Tumors of Childhood

Approach to Small Round Cell Tumors of Childhood

Fine-needle aspiration biopsy diagnosis of small round cell tumors of childhood: A comprehensive approach.

Fine-needle aspiration biopsy findings in small round cell malignant tumors of children are briefly reviewed. All of these tumors usually have characteristic cytomorphology which, when recognized, may lead to a definitive diagnosis. However, when these tumors are undifferentiated, morphologic criteria may not be sufficient for arriving at a correct diagnosis. A variety of ancillary studies including electron microscopy, immunohistochemistry and DNA ploidy, cytogenetics, and fluorescent in situ hybridization may provide valuable additional information for precise characterization of these neoplasms. Some of the ancillary studies may also be used for assigning these cases to prognostically significant subgroups. This information may also help in defining the most suitable chemotherapeutic regimens for these tumors. Since most of these special studies require only a small amount of cellular material, fine-needle aspiration biopsy is ideally suited for obtaining samples for these procedures. It is hoped that as cytogenetic and molecular techniques become available in many diagnostic laboratories, a comprehensive evaluation of aspiration biopsies from round cell malignant tumors, encompassing a precise pathologic diagnosis, determination of prognosis, and prediction of response to therapy, will be possible in a majority of cases. Diagn. Cytopathol. 1999;21:81-91.