[Imaging features of primary bone lymphoma and its histopathology]

To study the imaging features of primary bone of the lymphoma PLB on X-ray, CT and magnetic resonance imaging (MRI).

The data of 8 patients (6 males and 3 females, aged 9-60 years with a median age of 26.5 years) with pathologically confirmed PLB were retrospectively reviewed. Plain radiographs were obtained in all the 8 cases, CT scans performed in 5 and MRI examinations in 7. Four patients underwent X-ray, CT and MRI, two underwent CT and MRI, and one underwent X-ray and MRI. Surgical resection was performed in 7 cases and biopsy done in 2, and routine histopathological examination and immunohistochemistry were performed for all patients.

The site of PLB focus was found in the pelvic bone in 4 cases, right frontal bone in 1 case, proximal femoral bone in 1 case, occipital clivus in 2 cases, and vertebral column in 1 case. Plain X-ray revealed in 4 cases roughly normal shape of the involved bone with stippled interior bone structure destruction; the other 4 cases presented with slight or moderate bone expansion with obvious signs of osteolysis. CT scans displayed areas of different sizes of osteolytic cortical and marrow cavity destruction with large soft tissue masses around the lesion. MRI found heterogeneous iso- to hyperintense signals in the lesions in the bone and soft-tissue masses on T2-weighted images but homogeneous isointense signals on T2-weighted images. The tumors were obviously enhanced after contrast-enhanced scans on CT and MRI. Histological examination identified B-cell lymphoma in 5 cases and T-cell lymphoma in 4 cases.

PBL is characterized in imaging examinations by basically normal shape of the involved bones with possible bone expansion, obvious stippled osteolytic destruction, large soft-tissue mass around the lesion and obvious enhancement after contrast-enhanced scans.