Hello. Welcome to JA. Marrow signals are fairly common, thought to be due to excess lipid deposition or fat within the marrow. But a recent study found that not all reasons are benign, somewhere between 10% and 24% of patients with marrow signal abnormalities (heterogenous marrow signal) is associated with malignancy. Here is the abstract on the study from Boston (2013).
29,508 MRIs were performed and 77 patients met search criteria. Median age was 58 years with a median follow-up of 41 months at TMC after qualifying MRI. 40/77 (52%) of patients had either an MRI of the lumbar spine or hip with 21/77 (27%) undergoing work-up for the marrow findings. Evaluations included CBC (38%), SPEP (24%), quantitative immunoglobulins (14%), free light chains (10%), peripheral blood flow cytometry (5%), bone marrow biopsy (19%), skeletal survey (14%), bone scan (48%), CT scan (24%), biopsy of other site (24%), and subspecialty referral (48%, 29% to oncology). Definitive diagnosis was assigned in 11/21 (52%) cases, with 5 being malignancies (1 follicular lymphoma, 2 multiple myeloma, 2 lung cancer). Three patients were later diagnosed with malignancy (breast cancer, myelodysplastic syndrome, merkel cell carcinoma) at a median of 19 months. Overall, 10% of patients with abnormal marrow on MRI were diagnosed with a malignancy. Conclusions: Incidentally noted abnormal or heterogeneous bone marrow signal on MRI was not inconsequential. Of those patients who underwent evaluation for the finding, 24% were diagnosed with a malignancy. We conclude that abnormal bone marrow findings on MRI should not be ignored, and given the rates of malignancy in our series, oncologists are ideally suited for this task.