Multiple myeloma diagnosed after contrast-enhanced computed tomography without renal complications: a case report with literature review.

In patients with multiple myeloma (MM), the use of contrast agents is generally contraindicated owing to the risk of acute renal failure. Despite precautionary statements in package inserts, guidelines note that the supporting evidence is limited. We report the case of a patient diagnosed with MM following contrast-enhanced computed tomography (CT) and discuss the clinical implications of contrast agent use. A 77-year-old woman presented with numbness of the right lower lip. Panoramic radiography revealed a radiolucent lesion with an unclear border in the right mandible. Contrast-enhanced CT, performed for suspected jaw carcinoma, demonstrated enhancing masses not only in the right mandible but also in the right skull, raising suspicion for MM. No adverse events were reported following contrast administration. A biopsy of the right mandibular lesion revealed plasma cell myeloma, and bone marrow aspiration confirmed symptomatic MM. Systemic chemotherapy resulted in tumor regression without renal dysfunction. Although renal failure occurs in approximately half the patients with MM, the risk of contrast-induced nephropathy is low in patients with normal creatinine levels, and contrast-enhanced CT does not appear to worsen renal function. When malignancy of the oral cavity is suspected, contrast-enhanced imaging may improve diagnostic accuracy. Further studies are needed to clarify the risk-benefit balance of contrast use in patients with MM without renal dysfunction, considering disease prevalence and the potential loss of diagnostic capability.