Primary non-Hodgkin's lymphoma of bone in children

Background: Primary non-Hodgkin's lymphoma of bone, often more simply referred to as primary lymphoma of bone, is a rare subset of non-Hodgkin's lymphoma in children. There are only a few small series of primary lymphoma of bone in children with long-term follow-up, and none have appeared in the orthopaedic literature. Methods: A review of our institution's Pediatric Tumor Registry identified fifteen cases of primary lymphoma of bone among 306 cases of diagnosed non-Hodgkin's lymphoma between 1970 and 2003. Retrospective evaluation included collection of demographic, clinical, radiographic, treatment, and follow-up data. A univariate analysis was used to assess the prognostic significance of risk factors with respect to survival of patients from this series and in a summary analysis of data collected from similar series in the literature. Results: The patients included ten male and five female patients with a mean age of 11.6 years. Most patients had a presenting complaint of pain and had swelling and/or tenderness on physical examination. Eight children had a solitary bone lesion, and seven had multiple bone lesions. Overall, the mean number of bones involved was 3.1 per patient. The femur and the pelvis were the most frequently involved bones. The ten surviving patients were followed for a mean of 13.6 years. Five patients died: three of disease progression, one of treatment-related complications, and one of an unrelated cause. The mean time from diagnosis to death was 2.1 years. Nine patients received chemotherapy only, whereas six patients received a combination of chemotherapy and radiation therapy. In the present study, an age of nine years or less was predictive of poor survival (p < 0.05). In the summary analysis of cases collected from the literature, advanced stage, young age, non-large-cell histology, and multiple-bone involvement were predictive of poor survival (p < 0.05). Conclusions: On the basis of the present series and a comprehensive review of similar series in the literature involving patients with primary lymphoma of bone, it appears that younger age, advanced-stage disease, multiple-bone involvement, and non-large-cell histology are associated with decreased survival as compared with older age, localized disease, single-bone involvement, and large-cell histology, respectively.