The molecular pathology of small round-cell tumours--relevance to diagnosis, prognosis, and classification

A case report on non-metastatic Ewing sarcoma of the lumbar spine in a young patient

BACKGROUND

Ewing sarcoma (ES), the second most common malignant bone tumor after osteosarcoma in the second decade, occurs in 0.9% of cases as the primary non-sacral form.

CASE

A 20-years-old male presented with acute paraparesis of bilateral lower limb and numbness following initial back pain for the last 6 months. Magnetic resonance imaging (MRI) of the lumbar spine revealed a 4 cm enhancing soft tissue mass at the L4/L5 vertebra extending into the spinal canal with compression of the thecal sac. The computed tomography (CT) of the chest, abdomen, and pelvis revealed aggressive lytic lesions in the L4 spinous process with soft tissue extension into the spinal canal with no other site of distant metastasis. He was treated with IV steroids (Injection dexamethasone 10 mg IV followed by 4 mg tablet dexamethasone q6h; subsequently tapered off). A core needle biopsy showed a small, round blue cell neoplasm, (suggestive of a primitive neuroectodermal) stained positive for CD99 and vimentin stain. The diagnosis of ES lumbar spine was made which was treated with surgical resection with an appropriate margin measuring 8 × 4.5 × 2.5 cm with decompression and L4/5 laminectomies, which had a negative margin in the surgical pathology report. Concomitant local radiotherapy and chemotherapy [cycles of vincristine 2 mg/m² , adriamycin/doxorubicin 75 mg/m² , cyclophosphamide 1200 mg/m² (VDC) with mesna rescue alternating with cycles of ifosfamide 1800 mg/m² and etoposide 100 mg/m² (IE)] was started. The motor strength was regained gradually with preserved spine biomechanics and oncological control with no recurrence in 2-year follow-ups.

CONCLUSIONS

The presentation of lumbar ES can vary from local pain and swelling to acute paraparesis. Timely diagnosis and treatment with multimodal therapy, namely, steroids for acute spinal cord compression and surgery with chemoradiotherapy for ES can improve spinal biomechanics and oncological control.

Childhood cancer incidence and survival trends in Estonia (1970-2016): a nationwide population-based study

Background

Childhood cancers represent a small proportion of all cancers but are still a major public health problem. The study analysed long-term trends in childhood cancer incidence and survival in Estonia in relation to societal and health care transition.

Methods

Data on all malignant tumours, diagnosed in children aged 0–14 during 1970–2016, were derived from the Estonian Cancer Registry. Age-standardised (World standard) incidence rates were calculated by ICCC-3 site groups and joinpoint regression was used to estimate annual percentage change (APC) for incidence trends. Cohort and period approach were used to estimate 5-year survival. Internal age standardisation was applied.

Results

A total of 1628 incident cancer cases were diagnosed during the study period and overall incidence increased significantly at a rate of 0.5% per year. Significant increases were seen for neuroblastoma and germ cell tumours, for lymphoid leukemias and some CNS sub-sites. At the same time, decline in incidence was seen in almost all subgroups of unspecified neoplasms. The overall 5-year survival improved from 24% in 1970–1979 to 73% in 2010–2016, with the largest changes occurring in the 1990s and 2000s. For many sites, survival increase thereafter has been marginal.

Conclusion

In this first comprehensive population-based study of childhood cancer incidence and survival in Estonia, long-term trends are shown in the context of societal and health care changes. Even though the increasing incidence of some sites may, at least partially, be explained by improved diagnostics reflected in the decreased incidence of unspecified neoplasms, the overall cancer incidence in children seems to be rising. Rapid progress in diagnosis and care have improved childhood cancer survival immensely, but deficit in Estonia persists compared to other European countries. Results of the study accentuate the need for a more in-depth analysis of clinical data, but also for the prioritization of childhood cancer in Estonia, to ensure access to standard care and innovative treatments.

Sinonasal desmoplastic small round cell tumor: a case report and review of the literature

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a rare malignancy with poor prognosis that generally involves the peritoneum. Its diagnosis can be achieved only by immunohistochemistry and cytogenetic studies.

CASE PRESENTATION

In the current report, a 55-year-old female was admitted in our hospital for evaluation of right eye epiphora and right nasal intermittent bleeding. Imaging examination revealed a large soft tissue mass in the right nasal cavity and ethmoid sinus. After an explorative surgery, the pathological findings confirmed the presentation of sinonasal DSRCT. Immunohistochemistry and cytogenetic studies confirmed the diagnosis of DSRCT in this patient. Surgical resection, chemotherapy, and radiotherapy was performed, and she died 2 months after operation.

CONCLUSION

This reported case draws attention to the importance of novel treatments and including DSRCT in the differential diagnosis of sinonasal tumors.

Ewing's sarcoma in maxilla

Ewing sarcoma is a lesion of bone, described in small round cell neoplasm. This tumour resembles primitive neuroectodermal tumour both clinically and histologically. Major difference between these two is that the former arises in the bone and the later in soft tissue. It appears most frequently in males at the age range of of 5-25 years, 80% of which occurs within first two decades of life. Males are more commonly affected than females. Present paper reported with a case report of male patient with 24-year-old showing Ewing's sarcoma of right maxilla.

Ewing's sarcoma in maxilla

Ewing sarcoma is a lesion of bone, described in small round cell neoplasm. This tumour resembles primitive neuroectodermal tumour both clinically and histologically. Major difference between these two is that the former arises in the bone and the later in soft tissue. It appears most frequently in males at the age range of of 5-25 years, 80% of which occurs within first two decades of life. Males are more commonly affected than females. Present paper reported with a case report of male patient with 24-year-old showing Ewing's sarcoma of right maxilla.

Retrospective Analysis of Ploidy in Primary Osseous and Extraosseous Ewing Family Tumors in Children

Aims

To restrospectively study the DNA content in a series of childhood Ewing Family Tumors (EFT), and to investigate its prognostic value.

Methods

The study was performed on a series of 27 EFTs (osseous Ewing's sarcoma, 18 cases; extraos-sous Ewing's sarcoma, 2; peripheral neuroepithelioma, 4; Askin Rosai tumors, 3). Ploidy was investigated using both flow cytometry (FCM) and image cytometry (ICM) on tumor cell suspensions from formalin-fixed paraffin-embedded specimens or fresh frozen tissue obtained from the primary tumor at diagnosis.

Results

Ploidy was evaluable by FCM in all cases, and by ICM in 23/27. When fresh frozen tissue and paraffin-embedded samples from the same tumor were available for analysis, they yielded equal results. The rate of agreement between FCM and ICM was 82%. The majority of cases were diploid, and in the present series aneuploidy seemed to be associated with a poor outcome.

Conclusions

These results suggest that aneuploidy could be an indicator of a bad prognosis in EFT; however, the small number of cases precludes any conclusion of statistical value. Larger restrospective studies on ploidy using archival material could be performed and their reliability is supported by the concordance of results from fresh and formalin-fixed tissue.

Primary intracranial rhabdomyosarcoma of the cerebellopontine angle mimicking a vestibular schwannoma in a child

Primary intracranial rhabdomyosarcoma (PIRMS) is a rare neoplasm, which affects infants and young children. We report a rare case of a primary embryonal rhabdomyosarcoma of the cerebellopontine angle in a 7-year-old boy with clinical and radiological features mimicking a vestibular schwannoma. The patient underwent definitive surgery and radiotherapy and is recurrence free at 6 months. PIRMS commonly occur in parameningeal locations or metastasize to the brain from an extracranial primary. Gross total tumor resection followed by adjuvant radiotherapy remains the current standard of treatment; however, chemotherapy has also been tried with favorable results. The overall prognosis continues to remain poor.

An Unusual Location of Extraosseous Ewing's Sarcoma

Ewing's sarcoma (ES) is the second most common malignant bone tumor in children and young adults. ES also occurs as a primary soft tissue neoplasm without involvement of bone. We report the second case of extraosseous (EO) ES emerging from the omentum and a review of the relevant literature. EO ES should be included in the differential diagnosis of soft tissue neoplasms in the abdomen.

Treatment outcomes in 23 thoracic primitive neuroectodermal tumours: a retrospective study

OBJECTIVES

Thoracic primitive neuroectodermal tumour is an aggressive malignancy with poor survival despite multimodality treatment regimens. Early diagnosis of the tumour by histological, immunohistochemical, ultrastructural and cytogenetic techniques and early total surgical resection of the tumour with intensive chemoradiation may improve outcomes.

METHODS

Over 30 years, 23 patients (median age 29.5) with primitive neuroectodermal tumours (15 chest wall, 4 lung, 3 costovertebral sulcus and 1 anterior mediastinum) were diagnosed by transthoracic needle biopsy (43%) or excisional biopsy (57%). Treatment of a localized disease (Stage I and II) in 19 patients included surgery (wide excision of chest lesions in 11, 4 lung resections, excision of 3 costovertebral sulcus and 1 anterior mediastinal tumours, and resection of adjacent tissues involved by tumour en bloc) with adjuvant chemoradiation. Four metastatic chest wall tumours (Stage III) had chemotherapy and radiation alone.

RESULTS

Tumour recurred in 5 (2 chest wall, 2 costovertebral sulcus and 1 lung) requiring further chemotherapy, radiation and completion pneumonectomy for a lung recurrence. The incidence of recurrent tumour in 7 years for Stage I was 21 vs 40% (P=0.4) for Stage II lesions and 16% after the neoadjuvant chemotherapy vs 30% (P=0.4) after adjuvant chemoradiation. Four with recurrence, except one with a chest recurrence, succumbed to second relapse (78-96 months). All four Stage III chest tumours succumbed to advanced disease (30 months). The Kaplan-Meier disease-free survival of the overall group (23 patients) was 82±2% at 5 years and 64±3% at 10 years. The 10-year disease-free survival of 19 patients with localized tumours was 76%, but was high at 90% for chest wall tumours and low 33% for costovertebral sulcus tumours (P≤0.01). The 10-year disease-free survival was 86% for Stage I vs 60% (P=0.02) for Stage II tumours; and 83% for neoadjuvant vs 76% (P=0.06) for adjuvant chemotherapy and radiation.

CONCLUSIONS

The primitive neuroectodermal tumours are aggressive neoplasms with poor prognosis. Early diagnosis and total surgical excision of localized tumours with neoadjuvant or adjuvant chemotherapy and radiation improved disease-free survival.

Ewing sarcoma/primitive neuroectodermal tumor of the kidney: clinicopathologic analysis of 34 cases

The present study describes the clinicopathologic analysis of 34 cases of Ewing sarcoma/primitive neuroectodermal tumor occurring in the kidney. The patients were 21 males and 13 females with an age range of 6 to 44 years. Clinically, patients presented with multiple symptoms including hematuria, pain, and/or lump in the abdomen. Nephrectomy was performed in most of the cases. Grossly, whole of the renal parenchyma was involved by a variegated tumor. Histologically, the tumor was composed of monomorphic, small, and round cells arranged in a variety of patterns. Rosettes, geographical areas of necrosis, and arborizing vascular pattern were the prominent histologic features. The nucleus was monomorphic and round. Anisonucleosis was also noted in some cases. The nucleus was mostly hyperchromatic. A mixture of hyperchromatic and powdery chromatin was noted in few cases. Immunohistochemically, MIC2 (CD99) was positive in 32 of 34 cases followed by neuron-specific enolase (9/12 cases), vimentin (8/14 cases), synaptophysin (1/8 cases), and S-100 protein (1/4 cases). Molecular analysis by reverse transcriptase-polymerase chain reaction that was carried out in 26 cases revealed presence of EWS-FLI-1 type 1 translocation in 12 cases, EWS-FLI-1 type 2 translocation in 10 cases, and both type 1 and type 2 EWS-FLI-1 translocation in 2 cases. Two cases did not demonstrate any translocation. Follow-up data were available for 17 of 34 cases. Local recurrence of the tumor was seen in 4 patients, and 10 patients were recorded to have distant metastasis in various organs, such as lung, bone, and lymph node, during the course of the disease.

Primitive neuroectodermal tumor arising in the abdominopelvic region: CT features and pathology characteristics

BACKGROUND

We analyze the computed tomography (CT) findings of a peripheral primitive neuroectodermal tumor (pPNET) arising in the abdominopelvic cavity and to improve understanding of the CT images of the tumor.

MATERIALS AND METHODS

Twelve cases of pPNET confirmed by histopathology were analyzed retrospectively. Image characteristics of CT scanning were analyzed and compared with the pathology of the tumors.

RESULTS

There were 8 males and 4 females with mean age of 34.5 years. Unenhanced CT images showed large heterogeneous and ill-defined or well-defined masses with multiple patchy hypodense areas. The average diameter was 9.8 cm (range 4.0-17.2 cm). Contrast-enhanced CT images showed variable heterogeneous contrast enhancement with multiple non-enhancement areas. 3 cases revealed metastasis and 4 cases invaded into adjacent organs. Pathology showed areas of degeneration and necrosis in all tumors. Cluster of differentiation 99 and neurone specific enolase were detected positive in 11 and 12 cases, respectively.

CONCLUSIONS

In conclusion, pPNET in the abdominopelvic cavity likely affects young adults with a slight male preponderance and tend to be large and aggressive. Although CT findings are nonspecific and variable, a large ill-defined or well-defined heterogeneous mass with multiple patchy hypodense areas reflecting their cystic degeneration and necrosis on pathology examination may suggest the diagnosis of pPNET.

Ewing's sarcoma: A case report of a 52-year-old woman with recurrent tumor and literature review

Ewing's sarcoma is the second most common primary sacral tumor. Ewing's sarcomas are rare, aggressive tumors with a tendency towards recurrence following resection and early metastasis. Although peak incidences are between the ages of 10 and 20 years, patients of younger or older age account for almost 30% of the cases. We report the case of a 52-year-old healthy female who presented with a 2-week history of pain in her right posterior thigh that was unable to be relieved by non-steroidal anti-inflammatory medicine and physical therapy. Magnetic resonance imaging demonstrated an irregular right presacral mass and core needle biopsy revealed a small, round blue cell neoplasm. Staging workup was normal and an open biopsy was positive for the ES translocation (22q12). The patient was treated with 17 cycles of vincristine, adriamycin and cytoxan with mesna rescue, alternating with ifosfamide and etoposide in addition to external beam radiation. Post-treatment imaging demonstrated complete resolution of the tumor. Six weeks post-treatment the patient presented with a recurrent tumor. This case emphasizes the importance of timely establishment of initial diagnosis, early metastasis in treatment responsive patients and under-utilization of positron emission tomography-computed tomography (PET-CT) during the treatment to detect sub-clinical metastasis.

Reverse transcriptase-polymerase chain reaction as an ancillary molecular technique in the diagnosis of small blue round cell tumors by fine-needle aspiration cytology

We evaluated the feasibility and usefulness of reverse transcriptase-polymerase chain reaction (RT-PCR) on fine-needle aspirates for categorization of small blue round cell tumors (SBRCTs). A total of 51 cases, including 25 Ewing sarcoma/peripheral primitive neuroectodermal tumors (PNETs), 11 rhabdomyosarcomas, 13 neuroblastomas, and 2 desmoplastic small round cell tumors (DSRCTs) were analyzed. The detection of the EWS-FLI1 (20/25) and EWS-ERG (4/25) fusion transcripts resolved 24 of 25 cases of Ewing sarcoma/PNET. The PAX3/7-FKHR fusion transcript was detected in 2 of 4 cases of alveolar rhabdomyosarcoma and the EWS-WT1 transcript in both cases of DSRCT. Tyrosine hydroxylase and 3,4-dihydroxyphenylalanine (dopa) decarboxylase transcripts were demonstrated in 10 of 13 cases of neuroblastoma. In comparison, immunocytochemical analysis resolved 19 (76%) of 25 Ewing sarcomas, 9 (82%) of 11 rhabdomyosarcomas, 6 (46%) of 13 neuroblastomas, and 1 (50%) of 2 DSRCTs. Overall, RT-PCR resolved 38 (86%) of 44 vs 35 (69%) of 51 cases by immunocytochemical analysis. RT-PCR is easily applied to fine-needle aspirates of SBRCT and greatly facilitates accurate tumor typing.

Fine needle biopsy and genetics, two allied weapons in the diagnosis, prognosis, and target therapeutics of solid pediatric tumors

The recognition that genetic defects identify some pediatric solid tumors and may represent prognostic markers has provided cytologists with an extra tool for dealing with such tumors. Using some entities as archetypes, we discuss the importance of the association of fine needle biopsy and genetics, in the diagnosis, prognosis, and therapy selection of solid pediatric tumors. Immunocytochemistry is important to differentiate neuroblastoma, PNET/Ewing sarcoma, alveolar rhabdomyosarcoma, lymphoma, and desmoplastic small round cell tumor. Despite its usefulness in many cases, it is not conclusive and some of the aforementioned tumors even share the expression of some antibodies. The detection of specific diagnostic translocations will thus provide additional information and allows a precise cytologic diagnosis. Kidney tumors are also frequent in children. Although no genetic abnormalities have been identified so far in nephroblastoma, other kidney tumors, such as mesoblastic nephroma, whose cytology pattern can masquerade nephroblastoma, are also characterized by specific translocations. Kidney tumors in children have also been associated recently with typical genetic alterations such as Xp11.2RCC. Concerning prognosis and therapy selection, neuroblastoma is a sort of paradigm. The identification of MYCN oncogene status as an independent prognostic factor is determinant, not only in the assessment of clinical evolution, but also in the identification of risk groups, and consequently in the appropriate therapy selection. Cytopathologists should be aware of the genetic alterations characterizing pediatric tumors in order to collect extra material to perform cytogenetics, FISH, PCR, and Southern blotting, to achieve the correct identification of such genetic changes.

Diagnosis of the small round blue cell tumors using multiplex polymerase chain reaction

The small round blue cell tumors of childhood, which include neuroblastoma, rhabdomyosarcoma, non-Hodgkin's lymphoma, and the Ewing's family of tumors, are so called because of their similar appearance on routine histology. Using cDNA microarray gene expression profiles and artificial neural networks (ANNs), we previously identified 93 genes capable of diagnosing these cancers. Using a subset of these, together with some additional genes (total 39), we developed a multiplex polymerase chain reaction (PCR) assay to diagnose these cancer types. Blinded testing of 96 new samples (26 Ewing's family of tumors, 29 rhabdomyosarcomas, 24 neuroblastomas, and 17 lymphomas) using ANNs in a complete leave-one-out analysis demonstrated that all except one sample were accurately diagnosed as their respective category. Moreover, using an ANN-based gene minimization strategy in a separate analysis, we found that the top 31 genes could correctly diagnose all 96 tumors. Our results suggest that this molecular test based on a multiplex PCR reaction may assist the physician in the rapid confirmation of the diagnosis of these cancers.

Neuroblastoma incidence and survival in European children (1978-1997): report from the Automated Childhood Cancer Information System project

The Automated Childhood Cancer Information System (ACCIS) collects and presents data on childhood cancer in Europe. This report describes trends (1978-1997) and geographical differences (1988-1997) in incidence and survival for 6202 children with neuroblastoma from 59 registries in 19 countries, grouped into five regions (British Isles, West, East, North, and South). The age-standardised incidence rate (ASR) of neuroblastoma in Europe in 1988-1997 was 10.9 cases per million children, being highest in infants (52.6). The ASR of neuroblastoma increased in Europe from 8.4 in 1978-1982 to 11.6 in 1993-1997, mostly due to an increase in infants (from 35.4 to 57.8). Overall 5-year survival was 59%, ranging from 47% (East) to 67% (West). It improved markedly from 37% in 1978-1982 to 66% in 1993-1997, especially in infants. A certain amount of overdiagnosis in children under 2 years of age may explain the increased incidence rates and partially the increase in survival. Survival of older children (aged 2-14 years), which is likely to be largely affected by therapy, has also improved from 21% to 45%.

Procholecystokinin as Marker of Human Ewing Sarcomas

PURPOSE

Ewing sarcoma is a rapidly growing mesenchymal tumor in young adults. Although it was shown previously to express the cholecystokinin (CCK) gene, it is unknown whether CCK gene expression is detectable at protein level in Ewing sarcoma tumor cell lines, in tumor tissue, and in plasma from Ewing sarcoma patients, and, if so, whether CCK peptides might play a role as tumor markers.

EXPERIMENTAL DESIGN

CCK gene expression was evaluated with in situ hybridization or reverse transcription-PCR in tumor tissue. CCK precursors and bioactive CCK were measured with specific RIAs in tumor tissue, in cell culture medium, and in plasma of Ewing sarcoma patients before and after chemotherapy as well as after tumor recurrence.

RESULTS

CCK mRNA was identified in 12 Ewing sarcoma biopsies sampled in two series and in four Ewing sarcoma cell lines but not in unrelated neoplasia. Immunoreactive proCCK was identified in the culturing medium of all Ewing sarcoma cell lines but not in the media from unrelated tumor cell lines. Moreover, in plasma from Ewing sarcoma patients, precursors and mature forms of CCK, in particular proCCK, were detected; several fold elevation of the total proCCK product was found in plasma from patients before treatment and after tumor recurrence, whereas successful chemotherapy reduced proCCK to basal concentrations. Plasma concentrations of proCCK paralleled the respective tumor size.

CONCLUSIONS

This is the first study that consistently documents an altered CCK metabolism in human cancer; Ewing sarcomas synthesize and secrete proCCK that can be identified in plasma as circulating tumor marker.

Peripheral primitive neuroectodermal tumor of the chest wall of a 69-year-old man

We report a case of peripheral primitive neuroectodermal tumor (pPNET), which belongs to the pPNET/Ewing's sarcoma family, arising in the chest wall of a 69-year-old man. He had high levels of serum neuron-specific enolase and pro-gastrin-releasing peptide, which are believed to be useful diagnostic blood markers for small cell lung carcinoma (SCLC). Microscopically, the tumor was composed of solid nests and sheets of monotous, primitive, small round cells with a few rosettes, making it difficult to distinguish from SCLC. Immunohistochemically, the tumor cells showed intense cell membranous immunoreactivity for MIC2 protein (CD99). EWS/FLI-1 chimeric mRNA that originated from the characteristic t(11;22)(q24;q12) chromosomal translocation was detected by RT-PCR and nucleotide sequence analysis. These results confirmed the diagnostic validity of the present tumor being a pPNET, thus raising the possibility that in the past, pPNETs which have arisen in the chest have been mistakenly diagnosed as SCLC.

A case of peripheral primitive neuroectodermal tumor of the ovary

Peripheral primitive neuroectodermal tumor (PNET) belongs to the PNET/Ewing's sarcoma family. PNET is a small round cell tumor of putative neuroectoderm origin and is the second most common sarcoma among children and young adults. It may occur anywhere in the body and within any age group; however, it is most likely to occur in the bone and soft tissues. There have been a small number of case reports of PNET arising in the ovary. We presented a case of PNET arising in the right ovary of an 18-year-old woman. The tumor was metastased to the lymph nodes of the pelvis and para-aorta at surgical staging. We had persecuted Taxol/carboplatin chemotherapy, pelvic cavity radiotherapy, and Vincristine/Actinomycin, Cyclophosphamide/Doxorubicin (VACA). She died after 10 months due to septic shock.

Transdifferentiation of neoplastic cells

Transdifferentiation is a process in which a stable cell's phenotype changes to that of a distinctly different cell type. It occurs during certain physiological processes and leads to transition of tumor cell phenotypes. The latter process includes neoplastic epithelial-epithelial transition, neoplastic epithelial-mesenchymal transition, neoplastic mesenchymal-epithelial transition and transition between non-neural and neural neoplastic cell. This phonomenon is exemplified in some origin-debated tumors, such as carcinosarcoma, pleomorphic adenoma, synovial sarcoma, Ewing's/pPNET, and malignant fibrohistiocytoma. We propose that differentiation disturbance of cancer cells should include not only undifferentiation and dedifferentiation, but also transdifferentiation as well. Tumor cell transdifferentiation may be influenced or determined by cellular genetic instabilities, proliferation and apoptosis, as well as by extracellular matrix and growth factors.

Ewing sarcoma of the small intestine

This report describes a rare case of Ewing sarcoma (ES) of the small intestine. The patient was a 9-year-old girl with progressive abdominal distension. Computed tomography showed a large mass in the small bowel. Histopathologic examination of the resected tumor showed ES with typical histologic, immunohistochemical, and ultrastructural features. The tumor recurred in the pelvic cavity 18 months after the original surgery. Molecular study of the recurrent tumor confirmed a diagnostic EWS-FLI1 gene fusion. This patient illustrates the unique occurrence of ES in the small intestine.

Extraskeletal Ewing sarcoma in a 77-year-old woman

Extraskeletal Ewing sarcoma (EES) is a rare soft tissue tumor that is morphologically indistinguishable from Ewing sarcoma of bone. It is usually found in young people, but several cases have occurred in patients older than 50 years. The differential diagnoses include other small, blue round cell tumors (SBRCTs) and other members of the Ewing family of tumors such as the primitive neuroectodermal tumor. We present a case of EES in the left inguinal region of a 77-year-old woman. The tumor was distinguished from other SBRCTs by lack of immunoreactivity for epithelial, lymphoid, vascular, neuroendocrine, neural, histiocytic, and muscle markers. Primitive neuroectodermal tumor was excluded because of the lack of neural differentiation by histologic analysis, immunohistochemistry, and electron microscopy. Extraskeletal Ewing sarcoma was confirmed by characteristic features on histologic analysis, histochemistry, immunohistochemistry, and electron microscopy and by the presence of the t(11;22)(q24;q12) fusion transcript detected by reverse transcriptase-polymerase chain reaction. This case serves to remind the reader that EES is not a tumor that occurs exclusively in young patients.

Primary spinal epidural extraosseous Ewing's sarcoma: report of five cases and literature review

Ewing's sarcoma is the most common malignant bone tumour occurring in children and adolescents and exists in two different clinicopathological entities: osseous Ewing's sarcoma (OES) and extraosseous Ewing's sarcoma (EES). Five cases of primary epidural EES are described, which presented with non-specific symptoms leading to a long diagnostic delay. The median age at diagnosis was 22 years (range 13-36 years). The median diagnostic delay was 3 months. All patients had one or more neurological deficits. All underwent surgical exploration with a laminectomy and partial resection followed by adjuvant radiotherapy to a dose of 46-50 Gy and chemotherapy with VAC (vincristine, adriamycin and cyclophosphamide) alternating with ICE (ifosphamide, cisplatin and etoposide) for at least six cycles. The mean follow-up period is 21.2 months (range 11-32 months). Four of the five patients achieved a complete remission and are disease free at the time of writing this report. Two patients have a residual neurological deficit--both having presented with long history of neurological deficit. Primary spinal epidural EES should be suspected whenever young patients present with back pain and/or radicular pain, have abnormal neurology and an extradural mass is demonstrated on MRI. Surgical excision followed by adjuvant radiotherapy (50 Gy) and combination chemotherapy (VAC alternating with ICE) achieved local and systemic control in these patients. A greater number of patients and longer follow up are required to evolve a generally accepted treatment policy for this aggressive but potentially curable malignancy.

Classification and diagnostic prediction of cancers using gene expression profiling and artificial neural networks

The purpose of this study was to develop a method of classifying cancers to specific diagnostic categories based on their gene expression signatures using artificial neural networks (ANNs). We trained the ANNs using the small, round blue-cell tumors (SRBCTs) as a model. These cancers belong to four distinct diagnostic categories and often present diagnostic dilemmas in clinical practice. The ANNs correctly classified all samples and identified the genes most relevant to the classification. Expression of several of these genes has been reported in SRBCTs, but most have not been associated with these cancers. To test the ability of the trained ANN models to recognize SRBCTs, we analyzed additional blinded samples that were not previously used for the training procedure, and correctly classified them in all cases. This study demonstrates the potential applications of these methods for tumor diagnosis and the identification of candidate targets for therapy.

Translocation (10;11;22)(p14;q24;q12) characterized by fluorescence in situ hybridization in a case of Ewing's tumor

It is well recognized that the identification by classic cytogenetics of t(11;22)(q24;q12) is a useful aid in the accurate diagnosis of Ewing's sarcoma and related tumors. This translocation induces the EWS/FLI-1 fusion transcript, which can be detected by reverse transcription-polymerase chain reaction. Recent studies have also used fluorescence in situ hybridization (FISH) to demonstrate the translocation. The authors coupled classic cytogenetics and FISH on tumor cells from the original specimen, the local recurrence, and the pulmonary metastasis as well as from the xenografted tumors in a case of extraosseous Ewing's sarcoma. FISH analysis not only confirmed the cytogenetic results but also allowed the identification of a tumor-specific chromosome change, consistent with a complex translocation, t(10;11;22), as well as revealed other chromosomal rearrangements on both metaphases and interphase nuclei of each material. In addition this technique served to identify, in the interphase nuclei of the original tumor, the clone that became dominant, from the cytogenetic point of view, in the lung metastasis and in the nude mice xenografted tumors. Current results indicate that the use of FISH on metaphases and interphase nuclei is an easy and reliable approach to complement or even to substitute classic cytogenetic studies for the detection of specific chromosomal rearrangements, especially for determining complex translocations and for describing tumoral clones with different cytogenetic markers.

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.

Soft tissue Ewing sarcoma--peripheral primitive neuroectodermal tumor with atypical clear cell pattern shows a new type of EWS-FEV fusion transcript

This study describes a new case of Ewing sarcoma (ES)-peripheral primitive neuroectodermal tumor (pPNET) with unusual phenotype and fusion gene structure. The tumor located in the inguinal area of a 15-year-old boy showed a highly aggressive behavior with hematogenous metastases after intensive chemotherapy and bone marrow transplant, causing death 28 months after diagnosis. The tumor displayed a clear cell pattern, and several neuroectodermal markers proved positive both in the original tumor and in xenografts. This neuroectodermal character was confirmed by electron microscopy. Moreover, cytogenetically the tumor has an unusual chromosomal rearrangement, t(2;22)(q13;q22,t(3;18)(p21;q23); representing a new EWS-FEV fusion type in which exon 7 of EWS gene is fused with exon 2 of FEV gene. This is the third published study of an ES-pPNET showing EWS-FEV fusion described, but it is the first study of a tumor with the aforementioned fusion points. These findings support the genetic and morphologic heterogeneity existing within the group of ES-pPNET tumors.

Endometrial endometrioid carcinomas associated with Ewing sarcoma/peripheral primitive neuroectodermal tumor

Three uterine tumors, each consisting of endometrioid carcinoma and Ewing's sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) are described. The diagnosis of ES/pPNET in each case was first established in the hysterectomy specimen because each ES/pPNET was misinterpreted on the endometrial biopsy specimens as a high-grade homologous sarcoma. The ES/pPNET element in each case consisted of solid masses of small- to medium-sized round cells without Homer-Wright pseudorosettes, glial or ganglion cells, true rosettes with central lumens, or medulloepithelial tubules. Each ES/pPNET exhibited focal positive immunostaining for neuron-specific enolase, diffuse staining for vimentin, and strong cell membrane immunoreactivity for O13 (CD99), the last finding providing the first clue to the diagnosis of ES/pPNET in each case. The diagnosis in each case was confirmed by detection of EWS/FLI-1 fusion transcript through reverse transcription polymerase chain reaction. We also examined O13 immunoreactivity retrospectively in 40 cases of malignant mixed mullerian tumors (MMMT) with homologous or heterologous elements. O13 immunoreactivity was not observed in the malignant epithelium or in the homologous or heterologous sarcomas. The immunoreactivity of O13 in round cell endometrial sarcomas provides a clue to the diagnosis of ES/pPNET.

Advances in cancer cytogenetics

As the end of the millenium approaches, recognition of the milestones achieved in the field of cancer cytogenetics is mandatory. With regard to cancer cytogenetics, the turning century can be divided in three main era: the pre-banding period that has posed important hypothesis and technical premises, the fruitful banding era that led to the discovery of the critical chromosomal rearrangements and cloning of cancer genes and the more recent revolutionizing era of molecular cytogenetics where technological advances permit a global visualization and high-level resolution of chromosomal alterations. J. Cell. Biochem. Suppls. 32/33:173-182, 1999.

Current aspects of the pathology of soft tissue sarcomas

In soft tissue sarcomas, advances in pathological techniques, including immunohistochemistry, cytogenetics, and molecular genetics, have improved diagnostic accuracy, confirmed or clarified interrelationships between tumor subtypes, and revealed mechanisms of tumorigenesis. Many sarcomas are associated with abnormalities of tumor-suppressor genes, and several types have been found to have specific chromosomal translocations. These data and correlative clinicopathologic studies, although confirming many traditional pathological views, enable refinement or reassessment of terminology and classification of some small round cell, spindle cell, pleomorphic, and lipogenic tumors. New factors are emerging for prediction of tumor behavior, which might ultimately relate to therapy once a wider range of treatment options becomes available. This article reviews these current aspects of sarcoma pathology.

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.

Primary orbital Ewing's sarcoma: report of a case and review of the literature

Primary orbital Ewing's sarcoma is a very rare condition. Since the first case was reported in 1950, only 7 other cases have been reported in the English literature. Herein we describe the ninth, the only bilateral and the youngest case of primary orbital Ewing's sarcoma occurring in a 2-year-old boy, who presented to us with bilateral painless proptosis. Tissue biopsy of the tumour was obtained through the nasal sinus. Immunohistological studies of the biopsy tissue confirmed the diagnosis of Ewing's sarcoma. No distant site of the tumour was found so this was considered a primary orbital tumour. Combined chemotherapy and radiotherapy without surgical resection achieved an encouraging result in that the patient has remained in remission for 30 months after completion of treatment. The successful use of combined chemotherapy and radiotherapy, without surgery, adds further support to evidence that surgical excision may be avoided in selected cases of primary orbital Ewing's sarcoma.

Use of tumor-specific gene expression for the differential diagnosis of neuroblastoma from other pediatric small round-cell malignancies

The differential diagnosis of neuroblastoma from other small round-cell tumors of childhood, although clinically of great importance, is sometimes difficult due to the almost indistinguishable appearance of such tumors by conventional microscopy. Because neuroblastomas are characterized by the synthesis of catecholamines, we investigated the possibility that expression of genes involved in this pathway could serve as a molecular marker for this disease. A reverse transcriptase polymerase chain reaction assay was used to analyze expression of tyrosine hydroxylase and dopa decarboxylase in 84 pediatric malignancies including 55 neuroblastomas, 6 Ewing's sarcomas/primitive neuroectodermal tumors, 7 lymphomas, 6 leukemias, 2 rhabdomyosarcomas, 6 osteosarcomas, and 2 phaeochromocytomas. Of the 55 neuroblastoma samples analyzed, 54 expressed clearly detectable levels of both genes. The one sample that did not express either of the genes was rediagnosed both clinically and by molecular genetic analysis as a Ewing's sarcoma. Of the 29 non-neuroblastoma tumor samples examined, the only tumor samples that expressed clearly detectable levels of both tyrosine hydroxylase and dopa decarboxylase were phaeochromocytomas. Like neuroblastomas, these tumors are characterized by high levels of catecholamines. These findings suggest that expression of genes involved in catecholamine biosynthesis may be useful for differentiating neuroblastoma from other small round-cell tumors of childhood.

Dual colour fluorescence in situ hybridization to paraffin-embedded samples to deduce the presence of the der(X)t(X;18)(p11.2;q11.2) and involvement of either the SSX1 or SSX2 gene: a diagnostic and prognostic aid for synovial sarcoma

Identification of the t(X;18)(p11.2;q11.2) and the fusion gene products, SYT-SSX1 and SYT-SSX2, associated with a high proportion of synovial sarcomas, has been shown to be a useful diagnostic aid. This study demonstrates the application of dual colour fluorescence in situ hybridization to paraffin-embedded samples to deduce the presence of the derivative X chromosome and also the position of the breakpoint on chromosome X at either the SSX1 or the SSX2 gene. This used region specific markers from chromosomes X and 18 and an optimized protocol involving microwave exposure. Novel and rapid scoring criteria were validated which circumvented potential problems of nuclear truncation and defining cell boundaries. This involved blind analysis of two negative sarcoma samples and three synovial sarcomas in which corresponding frozen material had been previously shown to have the translocation involving different SSX genes. Six new cases diagnosed as synovial sarcoma were also analysed; two monophasic and two biphasic case were deduced to have a breakpoint in the SSX1 gene, one monophasic case an SSX2 breakpoint, and one case did not show rearrangement of the region. The ability to analyse formalin-fixed, paraffin-embedded samples in this way has practical implications for aiding the diagnosis of difficult cases, recently ascribed prognostic relevance, and allows further retrospective studies to be carried out. The methodology is also applicable to the identification of other tumour specific translocations in paraffin-embedded material.

Embryonal rhabdomyosarcoma with only numerical chromosome changes. Case report and review of the literature

An embryonal rhabdomyosarcoma, presenting as a retroperitoneal mass in a 15-year-old girl, is reported. The histological and immunohistochemical picture was typical, except for the presence of focal chondroid differentiation. Interestingly, expression of the "muscle markers" desmin and alpha-sarcomeric actin was present in the latter areas. Cytogenetic analysis showed a hyperdiploid karyotype without structural chromosome changes. The pertinent literature on the subject is reviewed. Hyperdiploidy of the clonal type seems to occur frequently, but no characteristic karyotype is so far emerging.

Utility of cytokeratin subsets for distinguishing poorly differentiated synovial sarcoma from peripheral primitive neuroectodermal tumour

AIMS

Poorly differentiated synovial sarcoma (PDSS) is a round cell sarcoma that may be difficult to distinguish from other round cell sarcomas, such as peripheral primitive neuroectodermal tumour (pPNET), on histological examination alone. Furthermore, these two tumours may show overlapping immunophenotypes, as some cases of PDSS express CD99, and, on the other hand, pPNET may express epithelial markers. The goal of this study was to determine the utility of cytokeratin (CK) subsets in distinguishing between these two lesions.

METHODS AND RESULTS

We evaluated 13 cases of pPNET with RT-PCR detected EWS/FLI-1 fusion transcript and 21 cases of PDSS for the immunohistochemical expression of CK7 and CK19. All cases of PDSS had areas of recognizable monophasic or biphasic synovial sarcoma that expressed at least one epithelial marker. Thirteen of 21 (62%) PDSS stained with AE1/AE3. CK7 and 19 were expressed in 11 (52%) and nine (43%) cases, respectively. Although six of 19 (32%) PDSS demonstrated cytoplasmic staining for CD99, none showed a membranous pattern of immunoreactivity. In contrast, 12 of 13 (92%) pPNET showed strong membranous immunoreactivity for CD99. Four tumours (31%) showed focal staining with AE1/AE3, two of which (15%) stained for CK19. CK7 was not detected in any of the pPNETs.

CONCLUSIONS

Although AE1/AE3 may be found in up to 31% of cases of pPNET, the expression of CK7 makes this diagnosis less likely.

Role of electron microscopy and other special techniques in the diagnosis of childhood round cell tumors

A series of case presentations show unique challenges associated with childhood round cell tumors and the role of ancillary techniques in diagnosis. Electron microscopy is shown to be the most powerful individual technique. Immunohistochemistry is less effective but also essential. Other ancillary techniques may provide needed additional diagnostic information. Because this is an area where it is of great importance to secure the most rapid, accurate, and specific diagnosis possible, an integrated multimodal approach is recommended--incorporating light microscopic, electron microscopic, and immunohistochemical studies as a matter of routine, and providing for cytogenetic and/or molecular diagnostic studies as indicated.

Peripheral primitive neuroectodermal tumor of the ovary confirmed by CD99 immunostaining, karyotypic analysis, and RT-PCR for EWS/FLI-1 chimeric mRNA

We report a case of peripheral primitive neuroectodermal tumor (pPNET), which belongs to the PNET/Ewing's sarcoma family, arising in the left ovary of a 29-year-old woman. Microscopically, the tumor was composed of solid nests and sheets of monotonous, primitive, small round cells with a few rosettes, making it difficult to distinguish from small cell carcinoma of the ovary. Immunohistochemically, the tumor cells showed intense cell-membranous immunoreactivity for MIC2 protein (CD99). A short-term cell culture and karyotypic analysis revealed the tumor to possess a balanced t(11;22)(q24;q12) chromosomal translocation that is highly specific for tumors of the PNET/Ewing's sarcoma family. In addition, EWS/FLI-1 chimeric mRNA that originated from the characteristic chromosomal translocation was detected by reverse transcription-polymerase chain reaction. These results confirmed the diagnostic validity of the present tumor being a pPNET, thus raising the possibility that in the past, pPNETs which have arisen in the ovary may have been mistakenly diagnosed as small cell carcinomas of the ovary.

Pathological Society of Great Britain and Ireland, 176th meeting. London, United Kingdom, 7-9 January 1998. Abstracts

The identification of specific chromosome translocations in various sarcomas and the elucidation of their molecular consequences has raised the possibility of detecting their presence for diagnostic and prognostic purposes in a manner analogous to the haematological malignancies. However, it is important to correlate particular translocations, and also other genetic aberrations, with current histological diagnoses and the behaviour of tumours, in order to assess the potential benefits, if any, of identifying rearrangements. Recent developments which enable specific translocations to be identified in archival material are likely to play an increasing role in the assessment and, eventually, the management of patients with sarcomas.

Cytogenetics and the surgeon: an invaluable tool in diagnosis, prognosis and counselling of patients with solid tumours

BACKGROUND

Cytogenetic studies have become an important part of tumour characterization. In a minority of tumours cytogenetic and/or molecular studies may be of help for diagnosis, selection of treatment protocols and predicting outcome.

METHODS

This article reviews the literature on solid tumour translocations and established family cancer syndromes. In addition, the potential importance of genetics in management of patients with breast, ovarian and pancreatic carcinoma is reviewed.

RESULTS AND CONCLUSION

Cytogenetic analysis of tumours may help confirm the diagnosis when conventional histology demonstrates no evidence of differentiation along a particular tissue pathway. For patients with well defined cancer syndromes, cytogenetic and molecular analysis offers the prospect of screening to reduce the risk of malignant disease. For many malignancies the underlying genetic anomalies are gradually being elucidated. Further studies designed to demonstrate the significance of these findings can only be undertaken if tumour material is collected and stored in optimal conditions for cytogenetic and/or molecular biological studies.

Two unbalanced translocations, t(12;22)(p13;q11) and t(12;?)(p13;?), in an aggressive chronic B-cell leukemia: TEL gene analysis using FISH

The translocation t(12;22)(p13;q11) has been consistently described in myeloid malignancies and shown to result from a fusion between the TEL and MN1 genes. Previously described deletions of 12p in acute lymphoblastic leukemias have been recently shown to harbor undetected translocations involving the TEL gene at 12p13. We document a case of an aggressive chronic B-cell leukemia whose cells had trisomy 12 and two unbalanced translocations involving 12p13, including a t(12;22)(p13;q11) as shown by conventional cytogenetics and fluorescence in situ hybridization (FISH). The 12p13 breakpoint of the t(12;22)(p13;q11) was telomeric to the TEL gene, and the second unbalanced translocation with breakpoint 12p13 resulted in the deletion of TEL. This case demonstrates that TEL gene deletions may be relevant in cases of mature B-lymphoproliferative diseases.

Interphase cytogenetics and pathology: a tool for diagnosis and research

Karyotypic analysis by direct demonstration of DNA sequences in interphase nuclei has been termed interphase cytogenetics and can be applied to a wide variety of cellular material, including paraffin-embedded tissue, allowing detection of both numerical and structural chromosome aberrations. The principal established method in the fluorescence in situ hybridization (FISH) technique, but more recently primed in situ labelling (PRINS) has been employed, as illustrated in an accompanying paper in this issue of the Journal. Where there are defining cytogenetic abnormalities, as is the case for the detection of fetal numerical chromosome abnormalities and in some paediatric and soft tissue tumours, this approach has clear diagnostic applicability. In other circumstances, such as the investigation of most solid tumours, this technique is largely of research interest but, particularly with application to paraffin sections, in providing valuable information on the morphological distribution of molecular changes in both invasive and 'pre-invasive' lesions. Continued technical refinement and research application of this methodology will lead not only to greater clinical applicability but also to improved understanding of the pathobiology of tumours.