Ewing’s sarcoma/primitive neuroectodermal tumor

Qian X, Jin L, Shearer BM, et al. Molecular diagnosis of Ewing s sarcoma/primitive neuroectodermal tumor in formalin-fixed paraffin-embedded tissues by RT-PCR and fluorescence in situ hybridization. Diagn Mol Pathol. 2005 14 23-28. 

The best-known association between FEI-1 and human tumors relates to its fusion with the EWS gene on chromosome 22 (22ql2) in many examples of Ewing s sarcoma/ primitive neuroectodermal tumor (PNET).i An associated fusion protein results from that event, which probably plays a role in the evasion of cellular senescence. 

Folpe AL, Hill CE, Patham DM, O Shea PA, Weiss SW. Immunohistochemical detection of FLI-1 protein expression A study of 132 round-cell tumors with emphasis on GD99-positive mimics of Ewing s sarcoma/primitive neuroectodermal tumor. Am J Surg Pathol. 2000 24 1657-1662. 

Vakar-Lopez F, Ayala AG, Raymond AK, Czerniak B. Epithelial phenotype in Ewing s sarcoma/primitive neuroectodermal tumor. Int J Surg Pathol. 2000 8 59-65. 

Neuroblastomas are small, round, blue cell tumors that may arise in the adrenal gland and a variety of extra-adrenal sites. The differential diagnosis is wide and includes rhabdomyosarcoma, Ewing s sarcoma-primitive neuroectodermal tumor (ES-PNET), medulloblastoma, small cell osteosarcoma, lymphoblastic lymphoma, blastematous Wilms tumor, and small cell desmoplastic tumor. Numerous markers have been used for the diagnosis of neuroblastomas including NE markers, cytoskeletal proteins, catecholamine-synthesizing enzymes, and neuroblastoma-"specific antibodies (Eig. 

CD99 is a useful marker for the distinction of neuroblastomas from other small, round, blue cell tumors. More than 100 cases of neuroblastoma have now been studied for CD99, and all have been negative. In contrast, nearly 100% of cases of Ewing s sarcoma-primitive neuroectodermal tumor (ES-PNET) are CD99-positive. Anti-Pi-microglobulin is another marker that is negative in neuroblastoma but positive in approximately 75% of ES-PNET. ... 

In addition to the small-cell tumors presented in the foregoing sections, others of a metastatic nature also may involve the mediastinum. These include small-cell osteosarcoma and Ewing s sarcoma/primitive neuroectodermal tumor (PNET) of bone, as well as small-cell malignant melanoma. Except for the last of these possibilities, the primary lesion in such cases is typically obvious and there is no question of whether the intra-thoracic neoplasm might have arisen there. Nonetheless, melanomas are certainly capable of producing distant metastasis in the absence of an obvious primary source. 

FIGURE 17.14 Ewing s sarcoma/primitive neuroectodermal tumor displays cohesive sheets of small- to medium-sized round cells with round to oval nuclei, fine chromatin, scant clear cytoplasm, and indistinct cell borders (hematoxylin-eosin, x200). 

FIGURE 17.16 CD99 (013) reactivity in Ewing s sarcoma/primitive neuroectodermal tumor typically shows a strong membranous and cytoplasmic staining pattern (immunoperoxidase x400). 

FIGURE 17.15 An immunohistogram of Ewing s sarcoma/primitive neuroectodermal tumor. 

FIGURE 17.17 Neuron-specific enolase is frequently positive in Ewing s sarcoma/primitive neuroectodermal tumor but can be seen in many other tumors (immunoperoxidase, x400). 

Ambros, I. M., Ambron, P. F., and Strehl, S. (1991) M1C2 is a specific marker for Ewing s sarcoma and peripheral primitive neuroectodermal tumors. Cancer 67, 1886-1893. 

Fetal fibroblasts myometrium vascular smooth muscle fetal myocardium vascular endothelial cells selected reticulum cells of lymphatic organs some CD30+ lymphoid cells (rarely) selected leiomyosarcomas, epithelioid hemangioendotheliomas, epithelioid angiosarcomas, primitive neuroectodermal tumors and Ewing s sarcomas, malignant peripheral nerve sheath tumors, and clear cell sarcomas... 

Myometrium fetal myocardium selected neoplastic myeloid cells some leiomyosarcomas rare primitive neuroectodermal tumors and Ewing s sarcomas... 

Anti-CD99 (M) Dako 1 20 MWER Recognition of virtually all primitive neuroectodermal tumors and Ewing s sarcomas labels roughly 50% of synovial sarcomas and malignant peripheral nerve sheath tumors also present in lymphoblastic lymphomas/ leukemias presenting in soft tissue... 

Gardner LJ, Polski JM, Fallon R, et al. Identification of CD56 and CD57 by flow cytometry in Ewing s sarcoma or primitive neuroectodermal tumor. Virchows Arch A. 1998 433 35-40. 

EM, extramammary EWS, Ewing s sarcoma FISH, fluorescent in situ hybridization Gl, gastrointestinal IHC, immunohistochemistry PNET, primitive neuroectodermal tumor. 

Dehner LP. Primitive neuroectodermal tumor and Ewing s sarcoma. Am J Surg Pathol. E993 E7 E-E3. 

Nilsson G, Wang M, Wejde J, et al. Detection of EWS/FLl-1 by immunostaining. An adjunctive tool in diagnosis of Ewing s sarcoma and primitive neuroectodermal tumor on cytological samples and paraffin-embedded archival material. Sarcoma. 1999 3 25-32. 

Molecular Detection of Ewing s Sarcoma and Primitive Neuroectodermal Tumor... 

Molecular Detection of Primitive Neuroectodermal Tumors and Ewing s Sarcoma... 

Pagani, A., Masri, L., Rosolen, A. et cd, (1998) Neuroendocrine differentiation in Ewing s sarcoma and primitive neuroectodermal tumors revealed by reverse-transcriptase polymerase chain reaction of Chromogranin mRNA. Diag Mol Pathol 7, 36-43. 

Liombart-Bosch, A., Pellin, A., Carda, C. et al (2000) soft tissue Ewing s sarcoma-Peripheral primitive neuroectodermal tumor with atypical dear cell pattern shows type EWS.EEV fusion transcript. Diag Mol Pathol, 9, 137-144. 

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