Imaging Features and Floating-Ice Sign of Primary Lymphoma of the Bone

Abstract

Background: The imaging presentation of primary bone lymphoma is unclear. Objectives: The present study aimed to investigate the imaging presentations of primary bone lymphoma especially a specific “floating-ice” sign. Patients and Methods: Forty one patients with primary bone lymphoma confirmed by pathology with 27 males and 14 females and an age range of 2 - 76 (mean = 40) years were enrolled. The clinical and imaging data were analyzed. Results: The tumor involved long bones in 17 cases, flat bones in 12, spine in eight and irregular bones in four cases. The imaging presentations were divided into five types: infiltrative type in nine cases (22%), osteolytic in 14 cases (34.1%), osteosclerotic in four cases (9.8%), mixed in 11 cases (26.8%) including four cases with a “floating-ice” sign and cystic in three cases (7.3%). In plain radiography, only three of four long bone lesions in children had a varying degree of periosteal reaction. Among 20 cases with CT scanning, sixteen had soft tissue masses, seventeen had ill-defined margins, and three had well-defined margins with sclerotic rims. Among twelve patients with MRI, ten had soft tissue masses with well-defined margins. MRI demonstrated a greater extent of lesion than CT. In MRI T1 weighted image (T1 WI), isointense signal was seen in three cases, hypointense signal in five and mixed signal in four. In T2 WI, isointense and hypointense signal was detected in five cases, hyperintense signal in three and mixed hyperintense signal in four. Conclusion: Primary bone lymphoma occurs most frequently in long and flat bones as infiltrative osteolytic destruction, and combined plain radiographs, CT and MRI help obtain a correct diagnosis.