Microglioma in a child - a further case in support of the microglioma entity and distinction from histiocytic sarcoma.

Microglia are not generally known to cause brain tumors but one bona fide case of adult microglioma has been published [9]. This tumor was highly malignant. We now report on a second, juvenile case, which showed a less aggressive course. Microglioma is a primary central nervous system (CNS) neoplasm distinct from glioma and other known brain tumor entities, based on its strong immunoreactivity for the macrophage marker CD163, the microglia marker Iba1, and the complete absence of neural as well as lymphocyte antigens. Furthermore, we have analyzed the literature and identified a number of cases that qualify as primary parenchymal histiocytic sarcomas of the CNS, which lack microglial morphology. Considering the non-hematopoietic developmental origin of the vast majority of microglia and the distinct morphological as well as immunophenotypic similarity of their neoplastic counterparts, we suggest using the term microglioma. More cases will be required along with appropriately-collected tissue to establish the molecular genetic profile of this extremely rare entity.

Flow cytometric analysis of Mixed phenotype acute leukemia: experience from a tertiary oncology center.

INTRODUCTION: Mixed phenotype acute leukemia (MPAL) is a rare subset of acute leukemia where the blasts exhibit lineage specific antigens of more than one lineage. Flow cytometric immunophenotyping is essential for the diagnosis of MPAL and the accurate diagnosis highly depends on the panel of markers used. The precise incidence of MPAL is uncertain as various institutions use different combinations of antibodies to assign the blasts to a particular lineage. AIM: The aim was to study the immunoprofile of acute leukemia including aberrant antigen expressions and to study the incidence, clinical features, laboratory findings, and immunophenotype of MPAL in our institution. MATERIALS AND METHODS: All cases of acute leukemias in which flow cytometric analysis during 1-year period from July 2012 to July 2013 were included in this study. RESULTS: During the study period, flow cytometric analysis of 506 cases was performed. B lymphoblastic leukemia was the most common subtype of acute leukemia. CD13 was the most common aberrant antigen expression in acute lymphoblastic leukemia and CD7 was the most common aberrant antigen expression in acute myeloid leukemia. A diagnosis of MPAL was made in 15 cases, which accounted for 2.96% of all leukemias. 9 cases were diagnosed as T/myeloid, 5 cases as B/myeloid and 1 case as B/T. CONCLUSION: Mixed phenotype acute leukemia is a rare subset of acute leukemia. Flow cytometry is critical in establishing a diagnosis of MPAL. The panel of antibodies used is important in the identification of the "mixed" phenotype. Cytoplasmic markers (cytoplasmic MPO, cytoplasmic 79a, cytoplasmic 22 and cytoplasmic CD3) should be included in the primary flow cytometric panel.

Guillain-Barre syndrome with acute lymphoblastic leukemia.

Guillain-Barre syndrome (GBS) is rarely reported in children with acute lymphoblastic leukemia and may be difficult to differentiate from vincristine induced neuropathy. We report two children with acute lymphoblastic leukemia on induction chemotherapy who developed GBS. The diagnostic issues and potential pathogenic mechanisms underlying GBS in pediatric patients with ALL are discussed.