Less commonly, MS represents an acute blastic transformation of myelodysplastic syndromes or myeloproliferative neoplasms. This rare condition commonly consists of a proliferation of more or less immature cells

with a myeloid immunophenotype, very exceptional cases showing a megakaryoblastic or erythroid differentiation. The most common MLN0128 localization of MS is the skin, lymph node, soft tissues and bones, but CNS involvement is exceedingly rare, with no cases reported in the sellar region. We report a 54-year-old man, affected by myeloproliferative neoplasm, JAK2 V617F-positive of 13 years duration, who acutely presented with a third cranial nerve palsy; neuroradiology documented a space-occupying lesion at the level of the sellar, upper clival and right parasellar regions, that was sub-totally removed with

a trans-sphenoidal approach. The histological examination documented a proliferation of large, blastic cells, frequently multinucleated; a diagnosis of MS with megakaryoblastic differentiation, arising in a background of chronic idiopathic myelofibrosis, was suggested by immunohistochemistry, owing to CD42b, CD45, CD61 and LAT (linker for activation of T cells) positivity. Dabrafenib order In addition, homozygous JAK2 V617F mutation was detected from the myeloid sarcoma specimen. A few weeks after surgery, an acute blastic leukemic transformation occurred and, despite chemotherapy, the patient died 2 months after surgery. To the best of our knowledge, else this is the first MS case with megakaryoblastic differentiation arising within the CNS. “
“To improve the diagnostic accuracy of oligodendroglial tumors and to find more convenient parameters that could predict the cytogenetic status, oligodendroglial and astrocytic tumors were cytogenetically and immunohistochemically investigated. Materials included 22 oligodendroglial tumors (15 oligodendrogliomas

and 7 oligoastrocytomas) and 20 astrocytic tumors. 1p loss was examined with the fluorescence in situ hybridization (FISH) method. Expression of GFAP, Olig2 and p53 was immunohistochemically investigated and co-localization of GFAP and Olig2 was evaluated on double-immunostained sections. Furthermore, TP53 mutation analyses were carried out on three oligodendroglial tumors showing p53 protein overexpression with a direct sequence analysis. Our FISH studies demonstrated 1p loss in 73% of oligodendroglial tumors (80% oligodendrogliomas and 57% oligoastrocytomas) and in only 10% of astrocytic tumors. There were no clear-cut morphologic differences between 1p-deleted and 1p-intact oligodendroglial tumors. GFAP and Olig2 were expressed in most oligodendroglial and astrocytic tumors, and their cellular localization was almost independent of each other. Overexpression of p53 was observed in five oligodendroglial tumors, all of which were 1p-intact.