Purpose: To report a case of synchronous prostatic cancer with multiple myeloma as inusual neoplasm presentation. To indicate the clinical data that they help to suspect the myeloma presence in the prostate bone metastatic disease.
Case report: Patient 63 years old diagnosed of prostatic carcinoma with bone metastasis and BAC good responsive, who have clinical deterioration, hypercalcemia and renal insufficiency.
Results: The presacred mass biopsy and extension study to find one second tumour (myeloma).
Conclusion: The presence of multiple myeloma must be to rule out when there are bone lytics injuries, well biochemical evolution with therapy and clinical deterioration, hypercalcemia and quickly progressive renal insufficiency.