Acute abdomen as initial manifestation of M4 - acute non-lymphocytic leukemia.

Visceral involvement in acute non-lymphocytic leukemia (ANLL) seldom precedes hematological manifestation. We report on a patient with M4 - ANLL presenting with acute abdomen without any evidence of blood disorder. Laparotomy revealed only ileal wall oedema. Postoperative clinical deterioration led to a second-look operation combined with intraoperative endoscopy. Biopsied tissues were diffusely infiltrated by blasts characterised as HLA-DR (+), PGM1 (50% +), MPO (50% +) and CD 34 (-). Bone marrow reconfirmed these findings and showed positivity for CD4 (44%), CD11b (50%), CD11c (42%), CD13 (33%), CD34 (32%), and CD56 (54%). Chemotherapy achieved a complete but short remission. Relapse occurred 7 months later. Immediately after consolidation chemotherapy the profoundly immunosuppressed patient passed away after a lower respiratory tract infection. We discuss the contrast between histology and short disease duration, the unusual presentation and the bad prognosis, and attempt to correlate the clinical course with the coexpression of markers.

An unusual case of CD4+ CD7+ CD56+ acute leukemia with overlapping features of type 2 dendritic cell (DC2) and myeloid/NK cell precursor acute leukemia.

Type 2 dendritic cell (DC2) acute leukemia has been recently described. We report here an unusual case of a 17-yr-old adolescent with overlapping features of DC2 and myeloid/NK cell precursor acute leukemia as defined by Suzuki et al. The patient presented with lymphadenopathy and hepatosplenomegaly without extranodal manifestations in skin or elsewhere. The morphologic, cytochemical and immunophenotypic features were compatible with those described in DC2 acute leukemia, with co-expression of CD4, CD56 and CD123 antigens. The novel markers BDCA-4 and BDCA-2 considered specific for DC2s were co-expressed. However, bright CD7 positivity along with a dim expression of CD33 (57%) and CD117 (27%) were also noted. Additionally, there was bright expression of NG2 monoclonal antibody 7.1, a frequent finding in myeloid/NK cell precursor acute leukemia. The interpretation of the immunophenotypic profile leads to the hypothesis on the existence of borderline cases between DC2 and myeloid/NK cell precursor acute leukemia. Still, other hypotheses can not be overlooked, such as the possibility for a kind of variant monoblastic leukemia or of another rare entity of acute unclassified leukemia.

Detection of CD55- and/or CD59-deficient red cell populations in patients with lymphoproliferative syndromes.

INTRODUCTION: Paroxysmal nocturnal hemoglobinuria is an acquired clonal stem cell disorder characterized by the decrease or absence of glycosylphosphatidylinositol-anchored molecules from the surface of the affected cells, such as CD55 and CD59, resulting in chronic intravascular hemolysis, cytopenia and increased tendency to thrombosis. PNH-phenotype has been described in various hematological disorders, mainly in aplastic anemia and myelodysplastic syndromes, while it has been reported that complete deficiency of CD55 and CD59 has also been found in patients with lymphoproliferative syndromes, like non-Hodgkin's lymphomas. MATERIALS AND METHODS: The presence of CD55- and/or CD59-defective red cell populations was evaluated in 217 patients with lymphoproliferative syndromes. The study population included 87 patients with NHL, 55 with HD, 49 with CLL, 22 with ALL and four with hairy cell leukemia. One hundred and twenty-one healthy blood donors and seven patients with PNH were also studied as control groups. The sephacryl gel microtyping system was performed for the detection of CD55- and CD59-deficient red cell populations. Ham and sucrose lysis tests were also performed in all samples with CD55 or CD59 negative populations. RESULTS: Red cell populations deficient in both CD55 and CD59 molecules were detected in 9.2% of patients with lymphoproliferative syndromes (more often in ALL and nodular sclerosis type of HD) and in all PNH patients. CD55-deficient red cell populations were found in 8.7% of LPS patients (especially in low grade B-cell NHL), while CD59-deficient populations were found in only two patients with low grade B-cell NHL. CONCLUSION: These data indicate a possible association between paroxysmal nocturnal hemoglobinuria phenotype and lymphoproliferative syndromes, while further investigation is necessary to work out the mechanisms and the significance of the existence of this phenotype in these patients.