A patient with prostate cancer and multiple myeloma-diagnostics and possible association of both diseases.

In this report, we describe a case of a patient with prostate cancer and multiple myeloma as the second metachronous malignant disease. To our knowledge, synchronous occurrence of bone marrow prostate cancer metastases and multiple myeloma-as it was found in the clinical disease course of our patient-has not been documented in the literature. Among other diagnostic procedures, cytomorphology and immunocytochemistry analyses contribute to detection of metastases of epithelial cells and synchronous plasma cell proliferation in bone marrow. Occurrence of multiple myeloma and prostate cancer in our patient adds to other similar reports and points to possible association between both diseases and also to other factors involved in the development of a second malignant disease. Further studies are needed to confirm and clarify this association, because prostate cancer is a relatively common malignant disease.