Ewing's sarcoma and the "peanut" tumors

Ewing's sarcoma

PURPOSE

The current treatments of and new therapeutic options for the management of Ewing's sarcoma (ES) are reviewed.

SUMMARY

ES is the second most common primary bone malignancy in pediatric patients and is numbered among the cancers that result in the greatest risk of mortality and morbidity in children and young adults. Much progress has been made in the treatment of ES since the disease was first described in the 1920s. With current multimodality treatment including chemotherapy, radiation, and surgery, patients with localized disease have a long-term survival rate of approximately 50%. Survival rates for patients with metastatic disease or those with early relapse remain poor. New combinations of cytotoxic agents such as cyclophosphamide, topotecan, irinotecan, and temozolomide have shown efficacy and tolerability in patients with relapsed or refractory disease. To date, the role of high-dose chemotherapy supported by stem cell rescue as a consolidation therapy for high-risk ES tumors has yet to be conclusively determined. Much effort is being invested in treating cancer with targeted therapies, and the EWS-ETS fusion gene would likely provide an important tumor-specific target. Tyrosine kinases (TKs) are overexpressed in human sarcoma tumors, and cell lines may serve as potential targets for new therapies. One TK receptor that is a promising therapeutic target is insulinlike growth factor-1 receptor.

CONCLUSION

Treatments for ES include surgery, radiation, and cytotoxic regimens, many of which include vincristine. Treatment for recurrent ES has included topotecan, cyclophosphamide, temozolomide, and irinotecan. Angiogenesis inhibitors, TK inhibitors, and bisphosphonates have also been studied.

Extraosseous localized ewing tumors: improved outcome with anthracyclines--the French society of pediatric oncology and international society of pediatric oncology

PURPOSE

To evaluate the outcome of children with an extraosseous Ewing tumor (EOE) according to treatment.

PATIENTS AND METHODS

Children with EOE were treated either with the strategy used for malignant mesenchymal tumors (MMTs) by the International Society of Pediatric Oncology (SIOP) or with the French Society of Pediatric Oncology (SFOP) regimen used for osseous Ewing tumors (OET). The MMT strategy included vincristine/actinomycin for small and resected tumors or ifosfamide/vincristine/actinomycin for unfavorable sites or unresectable tumors. Surgical excision was to be attempted after four courses, followed by local irradiation in case of residue. Osseous Ewing (OE) protocol included three courses of cyclophosphamide/doxorubicin followed either by two similar courses in case of good response or two courses of ifosfamide/etoposide in case of no response. After resection of the primary, treatment included conventional chemotherapy in case of good histologic response and high-dose chemotherapy and radiotherapy for poor response. All diagnosis specimens were reviewed by the panel.

RESULTS

Between 1989 and 1999, 63 patients were registered. Characteristics of patients treated by both protocols were similar. Five-year overall survival (OS) and event-free survival (EFS) of those treated with the OE protocol are 83% and 75%, respectively, which is significantly better than the OS and EFS of those treated with the MMT strategy (59% and 44%, respectively; P = .04 and .008, respectively). The size of the primary and the type of protocol influenced patients' EFS. In multivariate analysis, only the regimen had an impact on OS and EFS.

CONCLUSION

Our study shows that patients with EOE should be treated with OE regimens, probably because of the use of anthracyclines.

Pathology Abbreviated: A Long Review of Short Terms

Context.—Abbreviations are used frequently in pathology reports and medical records. Efforts to identify and organize free-text concepts must correctly interpret medical abbreviations. During the past decade, the author has collected more than 12 000 medical abbreviations, concentrating on terms used or interpreted by pathologists.

Objective.—The purpose of the study is to provide readers with a listing of abbreviations. The listing of abbreviations is reviewed for the purpose of determining the variety of ways that long forms are shortened.

Design.—Abbreviations fell into different classes. These classes seemed amenable to distinct algorithmic approaches to their correct expansions. A discussion of these abbreviation classes was included to assist informaticians who are searching for ways to write software that expands abbreviations found in medical text. Classes were separated by the algorithmic approaches that could be used to map abbreviations to their correct expansions. A Perl implementation was developed to automatically match expansions with Unified Medical Language System concepts.

Measurements.—The abbreviation list contained 12 097 terms; 5772 abbreviations had unique expansions. There were 6325 polysemous abbreviation/expansion pairs. The expansions of 8599 abbreviations mapped to Unified Medical Language System concepts. Three hundred twenty-four abbreviations could be confused with unabbreviated words. Two hundred thirteen abbreviations had different expansions depending on whether the American or the British spellings were used. Nine hundred seventy abbreviations ended in the letter “s.”

Results.—There were 6 nonexclusive groups of abbreviations classed by expansion algorithm, as follows: (1) ephemeral; (2) hyponymous; (3) monosemous; (4) polysemous; (5) masqueraders of common words; and (6) fatal (abbreviations whose incorrect expansions could easily result in clinical errors).

Conclusion.—Collecting and classifying abbreviations creates a logical approach to the development of class-specific algorithms designed to expand abbreviations. A large listing of medical abbreviations is placed into the public domain. The most current version is available at http://www.pathologyinformatics.org/downloads/abbtwo.htm.

Primary primitive neuroectodermal tumor of the uterus: a report of two cases and review of the literature

BACKGROUND

Primary primitive neuroectodermal (pPNET) tumors rarely occur in adults, and they very rarely present as primary tumors of the uterus. Only 12 reported cases of pPNET of the uterus have been published in the English literature. We report two additional cases treated at the Roswell Park Cancer Institute, Buffalo, NY, between 1999 and 2002.

CASES

Two postmenopausal patients presenting with abnormal uterine bleeding underwent endometrial biopsy, and subsequently staging laparotomy. The diagnosis of pPNET in both cases was confirmed only by extensive immunohistochemical analysis of the tumors. One patient with disease confined to an endometrial polyp received no adjuvant therapy, while the second patient with extrauterine disease received adjuvant pelvic radiation followed by chemotherapy.

CONCLUSIONS

The diagnosis of pPNET of the uterus may be a challenge. Features of diagnostic significance include positive staining with neuron-specific enolase, presence of neurosecretory granules, and positive staining with the MIC-2 gene. Currently, there is no uniformity in the treatment of these cases since the majority of the patients reported to date have had surgery, chemotherapy, and/or radiation therapy.

Establishment of an in vivo model for pediatric Ewing tumors by transplantation into NOD/scid mice

Ewing tumors are a clinically heterogeneous group of childhood sarcomas that represent a paradigm for understanding solid tumor biology, as they are the first group of sarcomas for which a chromosome translocation has been characterized at the molecular level. However, the biologic organization of the tumor, especially the processes that govern proliferation, differentiation, and metastasis of primitive tumor stem cells is poorly understood. Therefore, to develop a biologically relevant in vivo model, five different Ewing tumor cell lines and primary tumor cells from three patients were transplanted into immune-deficient mice via intravenous injection. NOD/scid mice that carry a complex immune deficiency and thus nearly completely lack the ability to reject human cells were used as recipients. Overall, 26 of 52 mice (50%) transplanted with VH-64, WE-68, CADO-ES1, TC-71, and RM-82 cells and 4 of 10 mice (40%) transplanted with primary tumor cells engrafted. Moreover, primary cells that did not grow in vitro proliferated in mice. The pattern of metastasis was similar to that in patients with frequent metastases in lungs (62%), bone marrow (30%), and bone (23%). Using limiting dilution experiments, the frequency of the engraftment unit was estimated at 1 Ewing tumor-initiating cell in 3 x 10(5) VH-64 cells. These data demonstrate that we have been able to establish an in vivo model that recapitulates many aspects of growth and progression of human Ewing tumors. For the first time, this model provides the opportunity to identify and characterize primitive in vivo clonogenic solid tumor stem cells. This model will, therefore, be instrumental in studying many aspects of tumor cell biology, including organ-selective metastasis and tumor angiogenesis.

Adamantinoma-like Ewing's sarcoma: genomic confirmation, phenotypic drift

Ewing's sarcoma, a highly malignant neoplasm, is characterized by an 11;22 translocation [t(11;22) (q24;q12)], resulting in the fusion of genes FLII and EWS. Adamantinoma of extragnathic bones, a low-grade malignant neoplasm with epithelial features, is not typically considered in the differential diagnosis of Ewing's sarcoma. In this study, three osseous Ewing's sarcomas with histological, immunohistochemical, or ultrastructural epithelial features were subjected to reverse transcription-polymerase chain reaction and sequencing studies for the Ewing's sarcoma molecular rearrangement. (Two of the three cases were originally described as adamantinomas or nontypical Ewing's sarcoma before the availability of genetic characterization.) In addition, traditional cytogenetic analysis and a unique combined interphase molecular cytogenetic/ immunocytochemical approach with bicolor 11;22 translocation breakpoint flanking probes (cosmids) and pancytokeratin antibodies were performed on one neoplasm. At(11;22) (q24;q12) was found in one neoplasm and a type II EWS/FLI-1 fusion transcript was detected in all three neoplasms. The combined genetic/immunocytochemical approach revealed the presence of the 11 ;22 translocation in the nuclei of cytokeratin immunoreactive cells. These genotypic and phenotypic findings delineate a novel Ewing's sarcoma histologic variant, "adamantinoma-like Ewing's sarcoma."

Primitive neuroectodermal tumor of the kidney confirmed by fluorescence in situ hybridization

Peripheral primitive neuroectodermal tumors (PNETs) are rare lesions that form part of the Ewing family of tumors, which includes osseous and extraosseous Ewing's sarcoma and Askins tumor of the thorax. All are characterized by translocations involving the EWS gene at 22q12, usually the translocation t(11;22)(q24;12). PNETs usually occur in soft tissues but occasionally arise within a visceral organ. We describe a PNET of the kidney that showed characteristic microscopic and immunohistochemical appearances of a small, round, dark blue cell tumor with focal rosette formation and strong membrane positivity for the MIC2 gene product. Interphase fluorescence in situ hybridization on touch imprints prepared from frozen tissue using cosmid probes flanking the EWS gene at 22q12 and the FLI1 gene at 11q24 indicated the presence of t(11; = +22)(q24; = +q12), confirming the diagnosis of PNET. This is the first reported PNET of the kidney supported by cytogenetic analysis. We also review the literature on this fascinating tumor in this unusual location.

Primary cutaneous Ewing's family sarcoma. Report of a case with immunostaining for glycoprotein p30/32 mic2

The differential diagnosis of cutaneous small round cell malignancies is a relatively uncommon but recurrent problem that usually requires adjuvant techniques including special histochemical stains, immunohistochemistry (IHC), electron microscopy (EM), and cytogenetics (CG) to arrive at a definite answer. This report describes a case of a primary cutaneous malignancy that, after workup, fulfilled the criteria of extraskeletal Ewing's family sarcoma, which was corroborated by IHC with an antibody to glycoprotein p30/32 mic2 that is highly expressed in these neoplasms. The lesions consisted of a large nodular proliferation of poorly differentiated monotonous small round cells confined to the dermis and subcutaneous tissue. The cells had high nuclear to cytoplasmic (N/C) ratios, scattered prominent nucleoli, and indistinct cytoplasm. A periodic acid-Schiff (PAS) stain with and without diastase demonstrated abundant cytoplasmic glycogen. The glycogen was confirmed with EM, which did not show neurosecretory granules, but extensive sectioning of the tissue blocks demonstrated with light microscopy a single focus with pseudorosette formation. IHC was positive for monoclonal antibody (MAb) O13 to glycoprotein p30/32 mic2 and negative for lymphoid (CD45), neural (S-100, NF, GFAP), neuroendocrine (NSE), and muscle (MSA, desmin) markers. To the best of our knowledge, this is one of few reported cases of primary cutaneous (extraskeletal/extraosseous) Ewing's sarcoma (EEWS) and the first to use IHC with MAb O13, which recognizes the cell surface glycoprotein p30/32 mic2. This case further illustrates the continuum between EEWS and primitive peripheral neuroepithelioma and supports the unifying concept that these two entities are merely subtle morphologic variants of the same malignant neoplasm, which is better designated a Ewing's family sarcoma.

Desmoplastic small cell tumor: a report of three cases and a review of the literature

PURPOSE

Desmoplastic round cell tumor (DSCT) is a highly malignant abdominal tumor first described in 1991, with subsequent cases predominantly noted in pathologic case reports. The authors evaluated response to alternating, intensive chemotherapy in three patients with DSCT, and reviewed the clinical experience with this newly described tumor as reported in the literature.

PATIENTS AND METHODS

Three adolescent boys with DSCT were treated intravenously with vincristine 2 mg/m2, doxorubicin 75 mg/m2, cyclophosphamide 1.8 g/m2, alternating with 5-day cycles of etoposide 100 mg/m2/day, ifosfamide 1.8 g/m2/day for a total of 11-15 courses.

RESULTS

Each patient showed initial tumor regression during chemotherapy, but developed progressive disease within 8-18 months. One patient subsequently showed a transient response to doxorubicin 45 mg/m2 plus 5-fluorouracil 500-600 mg/m2. All three patients died of disease within 20 months of diagnosis. A comprehensive literature review of clinical data on 101 reported cases of DSCT is presented. The median age was 21 years (range 6-38 years) with 78 male patients and 23 female patients. Ninety-nine cases involved tumor mass in the abdominal-pelvic cavity in proximity to the mesentery. Metastatic seeding to the omentum was most common, followed by spread of disease to liver, distant lymph nodes, lung, and occasionally to scrotum or to ovary. Tumor response to chemotherapy was noted in approximately 50% of 40 patients who received combinations of doxorubicin, cisplatin, cyclophosphamide, etoposide, and/or 5-fluorouracil. Four of 13 patients who received additional radiotherapy were alive at 24-48 months. Median survival was 17 months (range: 3-72 months), with only two patients reported disease free beyond 2 years at 40 and 48 months.

CONCLUSION

DSCT should be included in the differential diagnosis of small round cell tumors in children and young adults. Tumor regression has been noted during multiagent chemotherapy, but prolonged survival is rare with current therapies.

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

Substantial improvements have been made in the treatment and survival of children with SRCT, resulting in an increased emphasis on precise histological diagnosis. Although diagnostic procedures such as electron microscopy and immunocytochemistry contribute in poorly differentiated cases, an accurate diagnosis can remain elusive in a proportion of SRCTs. The cytogenetic and molecular genetic abnormalities characteristic of the different SRCTs can now be consistently and rapidly identified from minimal quantities of tumour material, using the techniques of FISH and PCR. This, coupled with the identification of novel phenotypic characteristics, has had a major impact on SRCT diagnosis. The aim of a tumour classification is to identify disease entities which are biologically distinct and whose recognition is of clinical value. The recent advances described above demonstrate that the SRCTs are genotypically and phenotypically distinct tumour types and that the genetic abnormalities represent key alterations that influence both the morphology and the clinical behaviour of the tumour. This suggests that these advanced phenotypic and genotypic analyses should form an integral and complementary part of the laboratory assessment and clinical management of these forms of paediatric cancer.

Diagnosis of Ewing's sarcoma and related tumours by detection of chromosome 22q12 translocations using fluorescence in situ hybridization on tumour touch imprints

It is increasingly recognized that the identification of t(11;22)(q24;q12) is a useful aid in the accurate diagnosis of Ewing's sarcoma and related tumours. However, cytogenetic studies have a low success rate and adequate tumour is not always available. This study describes the use of fluorescence in situ hybridization (FISH) to detect translocations at 22q12, the site of the EWS gene involved in t(11;22)(q24;q12), on tumour touch imprints made from true cut core-needle biopsy and frozen tumour. Of the seven tumours analysed, five diagnosed as Ewing's sarcoma or primitive neuroectodermal tumour demonstrated chromosome translocation at 22q12. This is a rapid and reliable method to detect a diagnostically relevant chromosome translocation using minimal amounts of fresh or frozen tumour.