Introduction

A variety of therapy regimens and toxin exposures can cause bone marrow changes. Post-therapy evaluation of the marrow may be useful to evaluate for residual disease, to assess the degree of marrow ablation, or to look for signs of marrow recovery. While proper marrow evaluation after therapy in individual patients requires knowledge of the type of prior therapy and original disease, some changes after therapy are common to all cases and vary primarily by the degree of marrow ablation.

General marrow changes after myeloablative therapy

There are many similarities in the marrow findings following high-dose chemotherapy or combined chemotherapy and radiation, as is often used in preparation for hematopoietic stem cell transplantation, and even after toxin or drug injuries to the marrow (Sale & Buckner 1988; van den Berg et al., 1989, 1990; Michelson et al., 1993; Wilkins et al., 1993). Common bone marrow changes after myeloablative therapy are summarized in Table 14.1. In the first week after the most severe types of injuries, the marrow shows complete aplasia with a complete or near-complete absence of normal hematopoietic elements and marrow fat. There is marked edema with dilated marrow sinuses, intramedullary hemorrhages, and scattered stromal cells, histiocytes, lymphocytes, and plasma cells. The histiocytes may contain cellular remnants, and fibrinoid necrosis may be prominent. Zonal areas of tumor necrosis may also be present, although myeloablative therapy is often given in the absence of prior marrow disease.