UNASSIGNED: Burkitt lymphoma (BL) is a common tumor of childhood that usually arises in the abdomen or pelvis in its sporadic form. In a minority of cases, BL can present with CNS involvement, usually as a secondary site. Rarely, BL can arise primarily in the epidural space and present with back pain, or less commonly, acute myelopathy. This presentation is a surgical emergency and requires vigilant management.
UNASSIGNED: We describe a case of pediatric BL arising primarily within the epidural space and presenting with progressive difficulty walking in a 3-year-old boy. Progression to complete inability to walk, absent lower extremity deep tendon reflexes, and new urinary incontinence prompted MRI of the spine, which showed a lesion extending from T5 to T10 and wrapping around the anterior and posterior portions of the spine with evidence of spinal cord compression. The patient underwent decompressive laminectomies from T5 to T10 and partial debulking of the posterior portions of the tumor. Microscopic examination showed a prominent \"starry sky\" pattern with abundant mitotic figures. Immunohistochemistry confirmed the diagnosis of BL. The patient is 10 months post-op and continues to undergo chemotherapy with partial neurologic improvement. He was free of recurrence 10 months post-operative.
UNASSIGNED: This appears to be the youngest described patient presenting with acute myelopathy in primary paraspinal BL. Management should include surgical decompression of the spinal cord followed by one of the various described chemotherapeutic regimens. Preoperative staging and neurologic function correlate with prognosis.

Attempts to establish a concise classification of lymphoblastic lymphomas (LBLs) have gained momentum in recent years, mainly due to the expanding possibilities of immunohistochemical and genetic characterization of different disease entities. Thus, cases of immature lymphoid malignancies with unusual immunopathological features have been reported during the last years, suggesting the need for new LBL classification concepts. To further characterize and demonstrate the extended spectrum of LBL, we present an unusual pediatric case of LBL that could not be categorized into one of the subgroups and exhibited a benign course after surgical treatment and subsequent chemotherapy. A mediastinal tumor of a 6-year-old Caucasian boy was examined by clinical staging, light microscopy, immunohistochemistry and PCR assays. The tumor cells reacted with TdT and had a positive cytoplasmic immunoreactivity for CD3. Further T- aand NK-cell markers CD1a, CD4, CD8, CD10, and CD56 reacted positively, but CD57, CD16 and CD 30 (Ber H2) were all negative. CD34 as a marker for bipotential B/T-precursors was also positive. B cell markers (CD20, CD22, Cd79a and IgM) were all negative. No clonal B cell Ig or T cell gamma chain rearrangements were detectable. Epstein Barr virus and other Herpes Virus DNA were not detected using a sensitive PCR assay. The applied chemotherapy was tolerated well and a complete remission of the tumor was achieved (observation period three years after the initial diagnosis). Localization, morphology, and the expressions markers made the tumor a typical member of the LBL group. However, our case represents a rare pediatric lymphoma derived from a thymic precursor committed to T/NK-cell differentiation and a favourable outcome after chemotherapy.