MRI APPEARANCE OF PRIMARY NON-HODGKINS-LYMPHOMA OF BONE

Objective. To evaluate the signal characteristics of primary non-Hodgk in's lymphoma of bone on MRI. Designs and patients. Ten patients with primary non-Hodgkin's lymphoma of bone were included in the study. T1- and T2-weighted imaging was performed. The signal intensity of the le sions was compared with that of the surrounding muscle. Results. The r esults of the MRI were compared with the histological findings. In the majority of cases (5/10) the lesion involved the femur. In one case e ach the tibia, humerus, ileum, sacrum, and skull, respectively, were a ffected. A soft tissue mass was present in four cases. In nine of ten cases on T1-weighted imaging the lesion was hypointense. On T2-weighte d imaging seven of ten lesions were hypointense compared with muscle, one isointense and, in two cases, part of the lesion showed slightly h yperintense signal. In all ten cases the signal pattern appeared inhom ogeneous. Pathological examination showed extensive fibrosis in the ma jority of cases. Conclusion. According to our results there is decreas ed signal intensity of bone marrow on both T1- and T2-weighted imaging , unlike other primary round cell tumors of bone. Because the diagnose s were established with small tissue biopsies, the reason for these fi ndings is speculative.