[Risk of underestimating platelet count because of the increase of mean platelet volume at the end of pregnancy]. / Risque de sous-estimation de la numération plaquettaire par augmentation du volume plaquettaire moyen en fin de grossesse.

We report the case of a pregnant woman for whom the platelet count (77 x 10(9)/L) was underestimated by Coulter STKS analyzer during the third trimester because of large platelets. The microscopic counting of platelets revealed an isolated thrombocytopenia (120 x 10(9)/L). When not pregnant, the patient has low but normal platelet count (155 x 10(9)/L) with high mean platelet volume (MPV > 12 fL). This case report recalls that concomitantly to the decrease in platelet count, the MPV significantly increases at the end of pregnancy. This poorly known phenomenon does not impair platelet count by blood cell analyzers in as much as the platelet volume is in the range of measurement but may be responsible for underestimation of the platelet count if the MPV is already high before pregnancy. We describe how to detect this anomaly and propose simple guidelines for thrombocytopenia in normal pregnancy.

[Acute myeloblastic leukemia without maturation (AML-M1) with basophilic elements and associated with translocation t(6;9)]. / Leucémie aiguë myéloblastique sans maturation (LAM1) avec éléments basophiles associée à la translocation t(6;9).

The clinical, hematological, and cytogenetic data from a 4 year-old child with acute myeloid (AML-M1) and basophilia is reported. Interestingly, cytogenetic investigations revealed the presence of the translocation t(6;9) (p23;q34). This abnormality is rare and associated with myelodysplastic syndromes or with subtypes of acute myeloid leukemia (M1, M2, M4, M7), usually with preceding or underlying myelodysplasia. The prognosis is poor, without response to chemotherapy regimen alone. Allogeneic bone marrow transplantation appears likely to be a more appropriate treatment.