Novel parameters in blood cell counters.

Many modern automated cell counters offer novel parameters. Some of these, such as the CHr, reticulocyte hemoglobin equivalent, or immature platelet fraction, schistocytes have been accepted by many clinicians; the CHr has even become part of clinical practice guidelines for dialysis patients. Other parameters are still research-use only and lack well-defined reference ranges. One important albeit rare clinical problem is to characterize platelet volume in case of inherited thrombocytopenia. Most novel parameters are specific for certain instrument platforms, and results of even similar parameters from different manufacturers are often difficult to compare.

A rare case of primary cutaneous follicle centre lymphoma presenting as a giant tumour of the scalp and combined with JAK2V617F positive essential thrombocythaemia.

Primary cutaneous follicle centre lymphoma (PCFCL) is a rare cutaneous B cell lymphoma in middle-age adults with excellent prognosis. Here we present a case of a patient with a PCFCL in the form of a giant tumour of the scalp in combination with a myeloproliferative neoplasm, JAK2V617F positive essential thrombocythaemia. This case may be of interest because of the favourable outcome in spite of the large size of the PCFCL, the rare combination with essential thrombocythaemia and because it contributes to discussion on the role of JAK2 mutation in such patients.

Platelet counting.

Platelet counting is a daily basic hematological analysis of crucial interest in many clinical situations. Historical manual techniques (phase-contrast microscopy) have been replaced by automated techniques (impedance or optical analyzers) more rapid and precise. More recently, flow cytometry techniques using labeled monoclonal antibodies have been proposed as reference techniques. Nevertheless, pre-analytical and analytical variables should be respected to obtain reliable results and avoid validation pitfalls.

Platelet morphology analysis.

Platelets are very small blood cells (1.5-3 µm), which play a major role in primary haemostasis and in coagulation mechanisms. Platelet characterization requires their counting (see Chapter 15 ) associated with accurate morphology analysis. We describe the major steps in order to correctly obtain stained blood films, which can be analyzed by optical microscope. Platelet morphology abnormalities are found in acquired malignant hematological diseases such myeloproliferative or myelodysplastic syndromes and acute megakaryoblastic leukemia. A careful analysis of the platelet size and morphology, by detecting either normal platelets with or without excessive anisocytosis, microplatelets, or large/giant platelets, will contribute to inherited thrombocytopenia diagnosis and gather substantial data when looking for an acquired platelet disorders.