It is not unusual for the myeloproliferative syndromes of polycythemia vera, myeloid metaplasia, and myelocytic leukemia to follow or subtly merge into one another. The occurrence of pernicious anemia preceding or following polycythemia vera is, however, distinctly uncommon. Such a case is reported by Engel and Stickney in a recent issue of the Archives of Internal Medicine.1 Seven years prior to their observation, the patient had received liver injections for 4 months because of anemia. Three courses of therapy with radioactive phosphorus were necessary for the control of polycythemia during the following 6 years. Two months after the last of these courses, a diagnosis of pernicious anemia was established on the basis of the characteristic blood picture, megaloblastic bone marrow, histamine-fast achlorhydria, and positive Schilling test. Adequate treatment with vitamin BB12 promptly restored the hemolytic abnormalities. Nine months later the polycythemia recurred and persisted.
The pathogenesis of this