Ewing sarcomas are an uncommon group of malignant neoplasms. A multidisciplinary approach is highly recommended to reach a correct diagnosis, considering the clinical, radiological, and ...histopathological aspects. Since in up to 90% of cases, the translocation t (11; 22) (q24; q12) occurs resulting in a chimeric fusion transcript EWSR1-FLI-1. The pathologist has several tools in addition to conventional techniques (hematoxylin and eosin), such as immunohistochemistry, which plays a very important role in the differential diagnosis. We present a series of 15 cases of molecularly confirmed ES, in which we found a sensitivity of 100% for CD99 and 80% for PAX8 by immunohistochemistry. This indicates a high sensitivity; however, it is known that both CD99 and PAX8 are also expressed in other tumours. Therefore, molecular confirmation should be performed in all cases.
Hemangioblastoma (HB) is a Central Nervous System (CNS) tumor with a generally favorable behavior and prognosis, classified as WHO grade 1. Sporadic HB is not related to any inherited disease, and it ...usually appears in a single location. Sporadic or VHL-related HBs show variable patterns of growth velocity. Cases of growing HB can cause mild symptoms such as headache, but some cases develop serious complications such as accumulation of cerebrospinal fluid in the brain with secondary neurological damage sometimes being irreversible when early treatment is not started. Our case showed some clinical characteristics more frequently observed in VHL-related HB rather than sporadic HB, and the presence of alterations inMDM2 and EGFR that could be related to the oncogenesis of these tumors. Even when the treatment of choice for HB is surgery, the presence of these genetic alterations could open a new window for research aimed at assessing the possibility of new therapies with TKIs-EGFR and anti-MDM2 inhibitors in those HB cases with multifocal recurrences or cases with an adverse clinical behavior. Keywords: haemangioblastoma, mouse double minute 2, epidermal growth factor receptor, hydrocephalus, immunohistochemistry, fluorescence in situ hybridization
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