1/48. Successful removal of a primitive neuroectodermal tumor in the lung with gross extension into the left atrium. We report here the successful multi-model treatment of a 31-year-old female demonstrating a primitive neuroectodermal tumor originating in the lower lobe of the right lung with gross extension into the left atrium via the inferior pulmonary vein. The tumor was markedly reduced by combination chemotherapy consisting of vincristine, doxorubicin, cyclophosphamide, and ifosfamide. The residual tumor was completely removed through a combined left atrial resection and right middle and lower lobectomy, using a percutaneous cardiopulmonary support system. ( info) |
2/48. Synovial sarcoma, histologically mimicking primitive neuroectodermal tumor/Ewing's sarcoma at distant sites. We report a case of synovial sarcoma (SS) showing unusual histology at distant sites. A 47-year-old man was aware of a tumor on the sole of his left foot. After preoperative chemotherapy with a diagnosis of SS, wide excision was performed. During postoperative chemotherapy, multiple tumorous lesions developed in the bone (including the whole spine) and both lungs. The patient died 1 year later. Histologically, the excised tumor of the foot showed a biphasic cellular pattern typical of SS, whereas at autopsy the bone and lung lesions were composed only of undifferentiated small round cells with cytoplasmic fibrillar processes. Homer-Wright rosettes were also observed. Immunohistochemically, 80% of the bone and lung tumor cells expressed MIC2 protein homogeneously. To clarify whether the bone and lung round cell tumors were metastatic lesions or second malignancies, especially primary primitive neuroectodermal tumor (PNET)/Ewing's sarcoma (ES), we performed reverse transcription-polymerase chain reaction (RT-PCR) analysis of tumor type-specific fusion gene transcripts. The SYT/SSX fusion transcript was identified in both the foot and lung lesions, whereas the EWS/FLI1 transcript was not detected in either lesion. Therefore, we concluded that the multiple bone and lung tumors were poorly differentiated metastatic tumors, which arose from the SS of the foot. We also conclude that the identification of chimeric fusion transcripts can be successfully applied to poorly differentiated sarcomas and will help in the differential diagnosis of tumors that cannot be distinguished by conventional morphological examinations. Also, it should be remembered that cytoplasmic staining for MIC2 protein may occur in sarcomas other than PNET/ES. ( info) |
3/48. Primary vulvar and vaginal extraosseous Ewing's sarcoma/peripheral neuroectodermal tumor: diagnostic confirmation with CD99 immunostaining and reverse transcriptase-polymerase chain reaction. Two cases of extraosseous Ewing's sarcoma/peripheral neuroectodermal tumor arising in unusual, superficial sites are reported. One tumor involved the vaginal wall of a 35-year-old woman, and the other neoplasm arose in the dermis of the vulva in a 28-year-old woman. The tumors showed characteristic microscopic features of Ewing's sarcoma/peripheral neuroectodermal tumor with nodular monotonous proliferations of undifferentiated, small, round, hyperchromatic cells with a low mitotic index. Rare rosette-like formations were apparent only in the vulvar neoplasm. The tumors displayed intense immunoreactivity in a membranous pattern for CD99, the cell surface glycoprotein encoded by the MIC2 gene. Genetically, the tumors expressed the EWS/FLI-1 chimeric transcript, derived from the t(11;22)(q24;q12) chromosomal translocation. Both patients had localized disease treated with wide local excision; one received postoperative chemotherapy, and the other received chemotherapy and radiotherapy. To date, 18 and 19 months after diagnosis, neither patient has had clinical evidence of local recurrence or metastasis. To our knowledge, these are the first reported cases of vaginal and vulvar Ewing's sarcoma/peripheral neuroectodermal tumor, confirmed with molecular genetic analysis, in the English literature. ( info) |
4/48. 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. ( info) |
5/48. Sinonasal teratocarcinosarcoma: ultrastructural and immunohistochemical evidence of neuroectodermal origin. The authors report a case of sinonasal teratocarcinosarcoma in a 37-year-old man, which was located in the anterior skull base and extended to the right nasal cavity and paranasal sinuses. The tumor was surgically resected twice, but it could not be removed completely. Microscopically, it was mainly composed of primitive cell nests within a moderately cellular stroma. The components of squamous cell epithelia with focal teratoid appearance and adenocarcinomatous differentiation were observed. There were many rhabdomyoblasts scattered in the nests and stroma. Ultrastructurally, the primitive cells had many neural processes with parallel microtubules, resembling olfactory neuroblastoma. Rhabdomyoblasts showed various degrees of skeletal muscle differentiation. Some of the stromal spindle cells had actin filaments with dense patches and dense core granules. Immunohistochemically, the primitive cells were positive for epithelial markers, neuron-specific enolase, synaptophysin, and myogenic regulatory proteins. The rhabdomyoblasts showed immunoreactivity for myoid markers, cytokeratin, epithelial membrane antigen, and synaptophysin. Most of the stromal spindle cells were positive for smooth muscle actin, neuron-specific enolase and synaptophysin. The immunohistochemical and ultrastructural findings suggest that primitive cells had the most primitive phenotype of placodes, and support the possibility that sinonasal teratocarcinosarcoma is essentially a neuroectodermal tumor with divergent differentiation. ( info) |
6/48. Melanotic neuroectodermal tumor of infancy (MNTI) of the hard palate: presentation and management. OBJECTIVE: To discuss the presentation and management of melanotic neuroectodermal tumor of infancy (MNTI) of the hard palate. METHOD: Case presentation and literature review. CASE: A 6-month-old girl presented with a slow growing, non-tender anterior oral hard palate mass. Radiologic imaging revealed a well-circumscribed cystic lesion containing teeth. After excision, histopathologic and electron microscopic evaluation revealed MNTI. No recurrence was seen at 12-month follow-up. CONCLUSIONS: This case and a review of the literature reveal MNTI to be a rare, benign hard palate tumor, which may present as a smooth, firm, painless, slow-growing anterior palatal lesion. Imaging reveals a well-circumscribed cystic lesion. Complete excision should be curative. Management requires attention to the potential need for palatal reconstruction, orthodontic care and correction of secondary nasal deformities. ( info) |
7/48. Primary primitive neuroectodermal tumor of the cauda equina. Primitive neuroectodermal tumors (PNETs) are aggressive neoplasms composed predominantly of undifferentiated cells that show evidence of neural differentiation. Although their classification has been controversial, PNETs are well recognized primary tumors of both central and peripheral nervous systems. PNETs must be distinguished from other round-cell tumors, including Ewing's sarcoma, lymphoma, rhabdomyosarcoma, and small cell carcinoma. Intraspinal PNETs are rare neoplasms that are usually metastatic in origin. We describe the eighth reported primary PNET of the cauda equina that developed in a 52-year-old man with no significant medical history. The tumor was characterized by Homer-Wright rosettes and immunoreactivity for CD99, glial fibrillary acidic protein, neuron-specific enolase S100, and synaptophysin. The anatomic location of primary intrathecal PNETs is important as those arising in the spinal cord develop in the central nervous system, whereas those arising in the cauda equina develop in the peripheral nervous system. The histogenesis of intrathecal PNETs may be multifactorial. ( info) |
8/48. The primitive neuroectodermal tumor of the heart. A young man was admitted to hospital with dyspnea, malaise, chest pain and night sweating. Investigative studies revealed a cystic mass lesion originating from the heart. Surgical exploration of the tumor showed that it was unresectable and pathology of the biopsy material was primitive neuroectodermal tumor. Medical literature concerning this unusual type of tumor is reviewed. ( info) |
9/48. Insulin production in a neuroectodermal tumor that expresses islet factor-1, but not pancreatic-duodenal homeobox 1. We studied a 60-yr-old female with a brain tumor who showed severe symptoms of hypoglycemia (plasma glucose, 2.2 mmol/L) and hyperinsulinemia (1.28 nmol/L) after radiotherapy. The cystic brain tumor contained proinsulin and insulin at concentrations of 13.6 and 1.22 nmol/L, respectively. Immunohistochemical studies showed the tumor cells were ectodermal in origin but not endodermal, based on three diagnostic features of neuroectodermal tumors 1) pseudorosette formation noted under light microscopy, 2) finding of a small number of dense core neurosecretory granules on electron microscopy, and 3) positive immunostaining for both neuronal specific enolase and protein gene product 9.5. These cells also expressed the transcription factor, neurogenin-3, NeuroD/beta 2, and islet factor I, which are believed to be transcription factors in neuroectoderm as well as in pancreatic islet cells, but not pancreatic-duodenal homeobox 1, Pax4, or Nkx2.2. In addition, they did not express glucagon, somatostatin, or glucagon-like peptide-1. Our results show the presence of proinsulin in an ectoderm cell brain tumor that does not express the homeobox gene, pancreatic-duodenal homeobox 1, but expresses other transcription factors, i.e. neurogenin3, NeuroD/beta 2, and islet factor-1, which are related to insulin gene expression in the brain tumor. ( info) |
10/48. Extraaxial primitive neuroectodermal tumor mimicking a vestibular schwannoma: diagnostic and therapeutic difficulties. Report of two cases. Extraaxial cerebellopontine angle (CPA) medulloblastomas and other primitive neuroectodermal tumors (PNETs) are rare tumors. The authors report on two patients with PNETs who presented with progressive audiovestibular symptoms. In each case magnetic resonance (MR) imaging revealed an extraaxial lesion that filled the internal auditory meatus and exhibited the neuroimaging features of a vestibular schwannoma (VS). No high signal intensity was apparent in either the brainstem or adjacent cerebellum on T2-weighted MR images. Surgery with maximum resection (total in one case and subtotal in the other) was performed, followed by craniospinal radiotherapy. One year postoperatively, both patients were free from tumor. A CPA PNET mimicking a VS is a rare entity, the diagnosis of which is important because its treatment differs dramatically from that of VS, including prescribed surgery followed by conventional craniospinal radiotherapy. ( info) |