CASE HISTORY • Part 1
A 67-year-old woman is referred for evaluation of anemia. She complains of gradually increasing fatigue and has recently noticed some abdominal distention and weight loss. She also describes difficulty eating a full meal due to early satiety.
Her past history is remarkable for the fact that several years ago she had been told by her gynecologist that she had very good blood counts with an elevated hematocrit and a tendency to a high white count. These findings were never evaluated. She had 2 uneventful pregnancies with no history of thrombosis or bleeding.
On examination she appears somewhat cachectic and pale. Her abdominal examination is remarkable for hepatomegaly and striking splenomegaly; the spleen tip is palpated nearly at the pelvic rim.
CBC: Hemoglobin/hematocrit - 7 g/dL/23%
WBC count - 3,500/μL with a decreased neutrophil percentage, but otherwise relatively normal leukocyte differential
Platelet count - 60,000/μL SMEAR MORPHOLOGY
Numerous "teardrop" red cells are noted, as well as occasional nucleated red cells. White cells appear decreased in number with no morphological abnormalities. Platelets are also decreased in number, and giant platelets are seen. Questions
What aspects of this case would lead the clinician away from a routine anemia workup?
How many hematopoietic cell lines appear to be involved in this disorder?
What additional laboratory studies are indicated?
Chronic myelogenous leukemia (CML) and the various myeloproliferative disorders are all clonal malignancies of the hematopoietic stem cell. In contrast to acute leukemia, they tend to have a more protracted clinical course as the malignant cells maintain the ability to mature during the chronic phase of the disease. Even if they present primarily as a proliferation of 1 cell line, cells of the granulocytic, erythrocytic, and megakaryocytic lineages can be shown to arise from the same abnormal clone. Moreover, overlapping between these disorders is frequent, either at presentation or during the disease course, providing a challenge to the clinician in the classification and management of the disease state.
The diseases that are commonly classified as myeloproliferative disorders are displayed in Table 19-1. The list traditionally includes chronic myelogenous leukemia, primary myelofibrosis, polycythemia vera, and essential thrombocythemia. A number of other conditions can, however, share characteristics with the myeloproliferative disorders. Chronic myelomonocytic leukemia, previously categorized as a primary myelodysplastic syndrome, is now considered more in the spectrum of myeloproliferative diseases. In addition, several of the dysplastic anemias share features with the myeloproliferative disorders, including the refractory anemias with excess blasts, and some instances of aplastic anemia (see Chapters 3 and 9). Chronic eosinophilic leukemia is also now recognized as a well-defined clonal entity.
TABLE 19-1Classification of myeloproliferative diseases |Favorite Table|Download (.pdf) TABLE 19-1 Classification of myeloproliferative diseases
Chronic myelogenous leukemia (BCR-ABL positive)
Chronic myelogenous leukemia (BCR-ABL negative)
Chronic neutrophilic leukemia
Primary (essential) thrombocythemia
Polycythemia vera (see Chapter 13)