Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (347 page)

   
Bone marrow biopsies
are valuable for distinguishing among the various MPNs and for monitoring disease progression or effect of therapy. Following the discovery of mutations in crucial genes, the diagnosis of MPNs is becoming both morphologic and cytogenetic/molecular.

   Classification

   Below is the revised (2008) WHO classification of MPNs, which includes the classic MPNs, and the atypical ones:

   Chronic myelogenous leukemia, BCR-ABL + [t(9:22)]

   Chronic neutrophilic leukemia

   Polycythemia vera

   Primary myelofibrosis

   Essential thrombocythemia

   Chronic eosinophilic leukemia, not otherwise classified

   Mastocytosis (not discussed further because of its rarity)

   
Atypical MPNs
: Myeloproliferative neoplasm, unclassifiable. These conditions include chronic myeloid disorders that are currently unclassifiable as belonging to either classical MPNs or myelodysplastic syndromes.

   The diagnostic approach of these entities will be presented under separate headings.

Suggested Reading

Spivak JL. Narrative review: thrombocytosis, polycythemia vera, and JAK2 mutations: the phenotypic mimicry of chronic myeloproliferation.
Ann Intern Med.
2010;152:300–306.

CHRONIC MYELOGENOUS LEUKEMIA (CML)

   Definition