Diseases that infiltrate the bone marrow are known as "myelophthisic" processes, and such disorders can be suspected on the basis of a "leukoerythroblastic" appearance to the peripheral blood in which there are nucleated RBC's and/or immature myeloid cells (metamyelocytes, myelocytes). Seen here is a metastasis from a carcinoma to the vertebral bone marrow. Metastatic prostatic adenocarcinoma to marrow is the best example of this process.

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