Primary diffuse large B-cell lymphoma of bone

Abstract

This thesis describes a study on primary diffuse large B cell lymphoma of bone with large patient numbers in chapter 2. The tumor presents mostly in the long bones. The clinical outcome is usually favorable. We found a trend towards worse survival for the immunoblastic tumor subtype. In chapter three, We studied the MRI characteristics of 29 bone lymphoma patients. The majority of the patients displayed a combination of definite cortical abnormalities and extension to the soft tissue, but up to 31% of the patients showed MRI features that looked radiologically non-aggressive or even benign. In chapter four, we determined the prognostic significance of BCL-6, CD10, MUM1, BCL-2, p53, CD30 and CD44. Applying the Hans__ algorithm, we concluded that 19 out of a cohort of 36 cases displayed a germinal center-like phenotype. No significant influence on survival was found. In chapter five, we investigated genomic alterations in nine cases. We found several recurrent genomic aberrations, but none had statistically significant prognostic influence. The most frequent finding was five cases with gain of 1q (five out of nine cases) and 2p16.1 amplification (four out of nine cases). In chapter six we investigated 50 cases for involvement of aberrant NF-_B activation by performing immunohistochemical stainings. In a minority (19%) of cases, we found substantial nuclear staining of p50. The nuclear expression of p50 was not preferentially detected in non-germinal center or germinal center type cases, or related to an inferior prognosis.