SEQUESTRA IN PRIMARY LYMPHOMA OF BONE - PREVALENCE AND RADIOLOGIC FEATURES

OBJECTIVE. Our objective was to determine the prevalence and spectrum of radiologic features of sequestra (detached pieces of bone separated from the involved segment) in cases of primary lymphoma of bone. This is a feature of primary lymphoma of bone that, to our knowledge, has not been reported previously. Recognizing sequestra is important, beca use a limited differential diagnosis of entities exists when this find ing is seen. MATERIALS AND METHODS. We retrospectively reviewed all th e clinical and pathologic information and radiologic studies in our ar chives on 434 cases of skeletal lymphoma. Of these, 246 met our criter ia for consideration as cases of primary lymphoma of bone. All cases w ere pathologically proved. Plain radiographs were available for review in all cases, and CT scans were available in 46. Data on the presence or absence of sequestra, their size and appearance, the bone involved , and the site of involvement were recorded in each case. RESULTS. Seq uestra were noted in 28 (11%) of the 246 cases. The size varied from 2 to 45 mm (average, 12 mm), and multiple sequestra were seen in 17 cas es. They were seen in the long bones (15 cases), axial skeleton (10 ca ses), and three other sites (scapula, calcaneus, and third metatarsal) . CONCLUSION. Sequestra have been reported in a variety of conditions, including osteomyelitis, eosinophilic granuloma, fibrosarcoma, malign ant fibrous histiocytoma, and desmoplastic fibroma. Because sequestra were seen in 11% of the cases of primary lymphoma of bone reviewed in this study, we believe that lymphoma should also be included in the di fferential diagnosis when a sequestrum is noted on imaging studies.