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Primary Bone Tumors
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
Jeremy S. Whelan, Rob C. Pollock, Rachael E. Windsor, Mahbubl Ahmed
Diagnosis is by biopsy, and it is important that the specimen is examined by a skilled pathologist in conjunction with the X-rays. The differential diagnosis will include non-malignant conditions such as osteomyelitis. An appropriate panel of immunocytochemical markers must be used to exclude lymphomas and carcinomas. Various degrees of neural differentiation will be indicated by markers such as S-100 and chromogranin, and expression of CD99, although not specific for Ewing sarcoma, is usually strongly positive. Access to molecular diagnostics to detect chromosomal translocations is essential and should be regarded as the gold standard for diagnostics.
Sarcomas
Published in Peter Hoskin, Peter Ostler, Clinical Oncology, 2020
Microscopically, Ewing's is composed of sheets of small round cells rich in glycogen. Ewing's is now considered to be one of the tumours in the group of PNET. The surface marker CD99 is characteristic for these tumours.
The locomotor system
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Ewing's sarcoma consists of sheets of small round cells with uniform pale nuclei and sparse mitotic activity (Figure 13.28). There is often intracellular glycogen and the cells usually express the cell surface antigen CD99. Ewing's tumour must be distinguished from other round cell tumours, e.g. lymphoma of bone and metastatic neuroblastoma in young children.
Ewing Sarcoma Displaying Extensive Well Differentiated Neuroblastomatous Differentiation: A Case Report
Published in Fetal and Pediatric Pathology, 2023
Nil Çomunoğlu, Cem Çomunoğlu, Rahşan Özcan, Süheyla Ocak
There are few reports of neurophil with varying degrees of ganglionic differentiation. In this presented case this component was prominent. Historically these tumors were named as “Peripheral neuroepithelioma/Malignant peripheral neuroectodermal tumor” including the so-called “Askin Tumor”. It has been claimed that the origin of these tumors might have been the migrating neural crest cells during embryogenesis [12]. This theory may explain the existence of ganglion cells in these tumors. As one of the two major neuroectodermal tumor group, ESs can be included in the same family with the other tumor group, neuroblastomas, which differentiate along the autonomic nerve cell lineage [7]. Well differentiated neuroblastomatous differentiation in ES cases may pose important diagnostic problems as in this case. Recognition of such feature may prevent a possible misinterpretation and a failure in oncologic treatment. Immunohistochemical markers are important in differential diagnosis. NKX2.2 is sensitive and moderately specific for ES [15]. CD99 is almost always immunopositive in diffuse and strong membranous staining pattern. FLI-1 and ERG are other positive staining helpful immunohistochemical markers. ES cases have FET::ETS fusion. t(11;22)(q24;q12) translocation resulting in EWSR1::FLI1 fusion and the t(21;22)(q22;q12) translocation resulting in EWSR1::ERG fusion are detected in most ES cases [6]. Detecting these rearrangements is often required for the diagnosis of ES and accepted as a desirable diagnostic criterion [6]. In our case, we have confirmed EWSR1/FLI fusion in both 1st and 2nd biopsy materials.
Primitive neuroectodermal tumor of the pancreas
Published in Baylor University Medical Center Proceedings, 2021
Ted George Achufusi, Raman Sohal, Ernesto Zamora, Prateek Harne, Ronald Russo
Primitive neuroectodermal tumor (PNET), a term coined by Hart and Earle, comprises a group of malignant neoplasms derived from multipotent progenitor cells of neuroectodermal origin.1 Since 1973, when it was first described, <100 cases have been documented.2 PNETs are rapidly growing soft tissue masses, highly malignant and invasive, with a high rate of relapse and a poor prognosis. They are characterized by undifferentiated small round cells that exhibit a neural phenotype. Often these cells resemble other small round cell tumors, so the diagnosis should be confirmed by immunohistochemistry. CD99, a product of the MIC2 gene, is expressed in >95% of Ewing’s sarcoma/PNETs.1,2 Although PNETs can occur in numerous solid organs such as the kidney, ovary, testis, uterus, urinary bladder, parotid gland, heart, lung, rectum, and pancreas, they are extremely rare, and <15 cases of PNET originating from the pancreas have been reported.3 PNETs primarily occur in children and young adults; however, they may present at any age, in any population. Our study reports the case of an otherwise healthy 61-year-old man diagnosed with advanced PNET of the pancreas.
Ultrastructure of CIC-DUX4 sarcoma: the first pathological report
Published in Ultrastructural Pathology, 2020
Hisashi Tamada, Mikiko Kobayashi, Kenji Sano, Takeshi Uehara, Yuki Matsumoto, Ayako Tateishi, Maki Ohya, Munehisa Kito, Kaoru Aoki, Hiroyuki Kanno
Since the CIC-DUX4 fusion gene was recognized in a portion of soft part sarcoma, numerous studies have been conducted to reveal the clinicopathological features of tumors containing this fusion gene. According to previous studies describing the histopathologic features of CDS, various tumor cell shapes and stromal myxoid changes are the distinguishing morphological characteristics between CDS and ES.2–7 In this study, we observed round, ovoid, spindle, and multipolar shaped cells with a stromal myxoid change in both cases. In the immunohistochemical examination, diverse CD99 expression, from absent to diffuse, and nuclear WT1 expression seems to be valuable features to distinguish CDS from ES.3–7 In these two cases, patchy CD99 positive staining was indicative to suspect CDS. We also observed nuclear WT1 expression in case 1. Cytologic features were also previously reported, describing pleomorphism of nuclear shape with prominent nucleoli contained therein.6 These features were also observed in our cases. To conclude, the histopathologic and cytologic findings from these two cases, which were cytogenetically confirmed, represent the typical features of CDS.