Extension of myeloid tissue into the lower extremities in polycythemia

Biopsies of the posterior iliac crest, greater trochanter, and proximal tibia were done for 27 polycythemic patients before myelosuppressive therapy was begun. Five had relative polycythemia, thirteen had secondary polycythemia, and nine had polycythemia vera. None of five biopsy specimens of the greater trochanter in cases of relative polycythemia contained myeloid tissue (erythroblasts, granulocytic precursors, and megakaryocytes). Four of six biopsy specimens of the greater trochanter and one of eight of the tibia in cases of secondary polycythemia contained myeloid tissue. All seven biopsy specimens of the greater trochanter and two of five biopsy specimens of the proximal tibia in cases of polycythemia vera contained myeloid tissue. A trochanter biopsy specimen devoid of myeloid tissue probably eliminates the diagnosis of polycythemia vera. Myeloid tissue extends from the axial skeleton to the greater trochanter, therafter to the tibia. Extension of myeloid tissue does not imply that marrow failure is imminent in polycythemia vera.