Cytokeratin expression in a congenital multipotential primitive neuroectodermal tumor

A case of an uncommon congenital primitive neuroectodermal cerebellar tumor (PNET) in a 5-month-old child is reported. After subtotal surgical resection, the residual tumor did not respond to radiation and chemotherapy. Histologically, the tumor was composed of small, round, undifferentiated cells and several other patterns like astrocytomatous, oligodendrogliomatous, and ependymomatous structures. Immunostaining was positive for most of the cells for vimentin and S 100, fewer were positive for glial fibrillary acid protein (GFAP) and neuron-specific enolase, and only a few for synaptophysin. Surprisingly, the tumor showed strong expression of several monoclonal cytokeratins (CK) with different molecular weights, together with epithelial membrane antigen. Furthermore, we found a coexpression of the tumor cells for CK and vimentin, while CK-GFAP and CK-S 100 were negative. Ultrastructurally, intracyto-plasmic intermediate filaments could be observed corresponding to immunohistochemical CK expression. The very strong CK and vimentin expression in this case was interpreted as a sign of the embryonic nature of the tumor.     

Differentiation of a primitive neuroectodermal tumor into a benign ganglioglioma

We describe a case of cerebellar neuroblastoma with histologic documentation of maturation into a ganglioglioma sixteen months later. Only chemotherapy was administered following the initial surgery and the child is well and disease-free three years following her final surgical procedure. The outcome of this patient supports previous hypotheses that the cerebellar neuroblastoma may be a less malignant tumor than its other primitive neuroectodermal posterior fossa counterparts. Furthermore, this case suggests a role for second-look surgery in the management of selected pediatric brain tumors.     

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.     

外周原始神经外胚层肿瘤形态学免疫表型及临床预后研究

目的：探讨外周原始神经外胚层肿瘤(PNET)的临床表现，病理及免疫组织化学特点及预后。方法：对15例外周原始神经外胚层肿瘤进行临床资料及预后，病理组织形态学和超微结构特点及免疫组化表型研究。结果：患者以男性为主，男女之比约为6．5：1，年龄6～35岁，年龄中位数为16，发生部位较多，可发生在直肠，腹膜后，腹股沟，淋巴结，胸壁，睾丸，鼻腔及骨组织等；免疫组化：肿瘤均弥漫表达CD99，并不同程度地表达NSE，SYN，CgA等，但不表达CK，Desmin，LCA等，其中1例表达组织化学染色PAS，随访最长时间为24月。结论：PNET是一种发生在年轻男性，进展迅速，预后非常差的恶性小圆细胞肿瘤，认识其临床病理特点及免疫组化表型对于该恶性肿瘤的诊断及临床治疗意义重大。     

Molecular Genetics in the Diagnosis and Prognosis of Solid Pediatric Tumors

The field of molecular genetics continues to see an ever increasing number of applications to pediatric tumor analysis. Studies in pediatric tumors have identified novel genes and other genetic changes, a large number of which reflect one of the following mechanisms: (1) activation of proto-oncogenes; (2) loss of tumor suppressor genes; or (3) creation of novel fusion proteins. At least one of these mechanisms is operational in each of the following pediatric tumors: neuroblastoma, Ewing sarcoma and peripheral primitive neuroectodermal tumor (pPNET), intra-abdominal desmoplastic small-cell tumor, rhabdomyosarcoma, synovial sarcoma, and Wilms tumor. Out of this research has come not only an increased understanding of oncogenesis but also, for each of the tumors listed above, diagnostic and/or prognostic markers that can be used by the pathologist and oncologist to improve overall patient management. Received November 20, 1997; accepted April 20, 1998.     

Experimental therapies in Ewing's sarcoma

Background: Ewing's sarcoma/primitive neuroectodermal tumours (ES/PNET) are aggressive musculoskeletal tumours with a predilection for young people. With current treatments, significant numbers of patients relapse and survival is poor for those with metastatic disease. Objective: To review current experimental treatment strategies in ES/PNET and prospects for the future. Methods: A review of the literature and recent meeting presentations on established and experimental cytotoxic and biological therapies in the treatment of ES/PNET was performed. Results/conclusion: New combinations of conventional and emerging cytotoxics show some promise. Molecular techniques are being used to identify high-risk patients and potential cellular targets. Several novel biologically targeted agents have demonstrated encouraging preliminary clinical efficacy; it is hoped these combined with current chemotherapeutic agents may improve outcome in ES/PNET.     

Primary spinal primitive neuroectodermal tumor: A single center series with literature review

Context: Primary spinal primitive neuroectodermal tumor (PNET) of the central nervous system has a low incidence. The intraspinal case is very rare. Around 30 cases have been reported so far. We summarized the cases of primary spinal PNET available in the database of our institute, either intramedullary or extramedullary cases. Then we did literature review of the same disease.Findings: There were eight cases of primary spinal PNET available in our database, with one intramedullary case and seven extramedullary cases. Surgical resection was performed. The histology diagnosis was PNET. Peri-operative image examinations of the whole central nervous system (CNS) were performed to exclude tumors other than spinal cord origin. Then during literature review, 33 reports of the disease were included. The pre-operative diagnosis rate was low. The disease had a high recurrence rate and poor prognosis given available treatment.Conclusion: Primary spinal primitive neuroectodermal tumor is of high malignancy. Little is known due to its quite low incidence. The prognosis is poor due to lacking of effective treatment strategy. Present treatment strategy is referred to other common CNS malignancies like glioma. Further investigation of the disease is necessary.