Background: Bone marrow abnormalities may be found in patients with cancers even without marrow metastases. We have seen that patients with non-hematologic neoplasias may show bone remodelling, stromal modifications, reactive changes and myelodysplastic alterations of erythro-, granulo- and megakaryocytic series comparable to those found in myelodysplastic syndromes (MDSs).
Methods and results: At the beginning of the study 58 bone marrow biopsies (BMBs), performed in 40 patients with previously diagnosed cancer from different primary sites but without marrow metastasis (group A), were evaluated. Osseous and stromal modifications, marked reactive changes, quantitative and qualitative alterations of erythro-, granulo- and megakaryopoiesis were observed. Afterwards, 30 BMBs from 20 patients without a previous diagnosis of neoplasia (group B) were found to have features similar to those discovered in group A. Further investigations detected malignant tumors in all these cases. The findings of the two groups were compared with our former observations on myelodysplastic syndromes. The main differences between groups A-B and MDSs regarded bone remodelling, stromal modifications and reactive changes.
Conclusion: These marrow alterations linked to a neoplasia may be considered paraneoplastic. They may cause problems for a differential diagnosis with some proliferative diseases and, above all, with primary MDSs. The reported features should prompt the pathologist to suggest a search for possible occult cancer.