Multiple Myeloma Involving the Thyroid Cartilage in a Patient with Prostate Cancer: a case report

Multiple myeloma (MM) involving the thyroid cartilage is an extremely rare disease. Only 11 cases have been reported in the English literatures. The diagnosis is difficult and challenging especially when patients present with an underlying malignancy. Herein, we report a case of MM with involvement of the spine and the thyroid cartilage in a patient with a medical history of prostate cancer. The patient clinically presented with acute lower back pain, a palpable neck mass, and hoarseness. Computerized Tomography (CT) images revealed osteolytic lesions in the spine, cortical thinning, expansion and destruction of the thyroid cartilage. Magnetic Resonance Imaging (MRI) of the neck mass exhibited T1 isointensity, T2 hyperintensity, water restriction on diffusion weighted images (DWI), and homogeneous enhancement on post-contrasted T1 weighted images (T1WI). This is the first report of thyroid cartilage MM presenting with DWI finding in the English literatures. The imaging findings and differential diagnosis are discussed in this report.