Acute promyelocytic leukemia
A 36-year old Caucasian male without a relevant medical history was admitted to the emergency ward of a local hospital (Albert Schweitzer Hospital, Dordrecht, The Netherlands), because of acute chest pain. An anterolateral myocardial infarct was diagnosed (laboratory results showed: Troponine-T: 0,35 µg/L (elevated) and CK: 453 U/L (elevated)) and the patient was referred to the cardiology department of the nearest university hospital (Erasmus Medical Center, Rotterdam, The Netherlands) for a percutaneous coronary revascularization procedure.
In the meantime the digital microscope, DM96 (Cellavision, Lund, Sweden), present at the local hospital, detected two blast cells with Auer rods in a routine 200-cell peripheral blood morphology screening. In combination with the acute coronary occlusion, this finding was highly suggestive of an AML-M3 (acute promyelocytic leukemia). This information was immediately communicated to our colleagues at the university hospital.
On admission in the university hospital, coronary arteriography revealed a thrombus in the proximal left descending coronary artery (LAD). No other vascular abnormalities of the coronary arteries were found. After uncomplicated thrombectomy and stent implantation in the proximal LAD, the CK was elevated to a maximum of 1481 U/L, the CK-MB to a maximum of 116 µg/L and the Troponine-T to a maximum of 3,11 µg/l. Other laboratory result showed a mild pancytopenia (haemoglobin 12 g/dL, leukocyte – and platelet count of 0,9 x109/L and 127 x109/L, respectively). Coagulation tests revealed a mild diffuse intravascular coagulation (APTT 26 sec (normal), PT 1,1 INR (normal), Fibrinogen 2,3 g/L, D-dimer 2,0 mg/L (elevated), AT-III 0,87 IU/mL (normal). Because an acute promyelocytic leukemia (APL) was suspected, bone-marrow sampling was performed showing 59% promyelocytes that were hypergranular and sometimes bi-lobulated. Auer rods were seen in several of these cells. The immunological PML test was positive, cytogenetic analysis revealed a translocation (15;17)(q24;q21) and molecular analysis confirmed the presence of the PML-RARA gene fusion product. The patient was diagnosed with an acute promyelocytic leukemia and treatment with retinoic acid and, since the left ventricular function was normal, idarubicine according to the Dutch national HOVON-79 protocol was started immediately. The results of the remission-induction course are not available yet.
This case nicely illustrates the superiority of the DM96 in the morphological detection of blast cells in peripheral blood. A recent study comparing morphological classification of 1,5 million leukocytes by the manual microscopical method and the automated digital microscope, DM96, shows a sensitivity of 100% in blast cell detection (Riedl et al., to be submitted for publication). Moreover this case report underlines the vital importance of good collaboration and communication between the clinician and clinical chemist, also in an inter-hospital setting.
1. Department of Clinical Chemistry, GKCL, Albert Schweitzer Hospital, Dordrecht, Netherlands.
2. Department of Haematology, Erasmus MC, Rotterdam, Netherlands.