Primary Central Nervous System Burkitt Lymphoma With Non-Immunoglobulin Heavy Chain Translocation in Right Ventricle: Case Report

Primary central nervous system Burkitt lymphoma (PCNSBL) is rare. Few cases of primary central nervous system involvement with sporadic Burkitt lymphoma have been reported and its treatment is now controversial. Here, the authors report a case of a 14-year-old boy suffering from non-immunoglobulin heavy chain (IgH) translocation PCNSBL. To the authors' knowledge, this is the second case report describing primary Burkitt lymphoma involving cerebral ventricles. After receiving combination treatment with surgery, stereotacticradiosurgery, and a chemotherapy regimen including high-dose methotrexate, the patient had a disease-free survival of 18 months.

Burkitt lymphoma (BL), rare and aggressive, is a form of B-cell non-Hodgkin lymphoma with a tendency to disseminate to the bone marrow and meninges [1]. Central nervous system involvement occurs in about 13% to 17% of adults [2] and 12% of children with BL [3]. However, primary central nervous system Burkitt lymphoma (PC-NSBL) is very rare. An extensive search of the literature showed that just a few cases of PCNSBL have been reported in the past 30 years; only one reported that the tumor located in the third ventricle and the left temporal horn [4].
Here, we present a case study about a 14-year-old boy who complained of intermittent blunt headache caused by PCNSBL and had a long-term survival after combination therapy.  (Figure 1). A giant cell astrocytoma or ependymocytoma was strongly suspected.

CASE REPORT
Surgery was preformed in December 2008 in our hospital and revealed a tumor, solid in nature, firm, fish-shaped, and having an affluent blood supply. The tumor, which was located in the right lateral ventricle, laterally closely adherent to the thalamus, was removed entirely. Postoperative hematoxylin and eosin (HE) staining of the tumor tissue showed a characteristic starry-sky appearance and medium-sized lymphocytes. Immunohistochemistry demonstrated CD20+, CD10+, CD79a+, BCL-6+, TdT−, MPO−, BCL-2−, CD3−, and Ki-67+ (>95%) (Figure 2). Fluorescent in situ hybridization (FISH) analysis (c-myc dual-color break-apart rearrangement probe; Vysis) found that MYC/IGH fusion probe was negative but MYC break-apart probe was positive for the tumor cells (Figure 3). Owing to interventricular foramen adhesion after his surgery, the boy repeatedly had intracranial hypertension, so a ventriculoperitoneal shunt was inserted 2 days after the initial operation. In order to exclude systemic  M. Jiang et al.

Primary central nervous system lymphoma (PCNSL) is an aggressive form of non-
Hodgkin lymphoma developing in the brain, spinal cord, eyes, or leptomeninges without evidence of systemic involvement [5]. Overall, PCNSL accounts for 0.5% to t(8;14), which (B) indicates that the partner of myc was probably IgL or some other gene.
The diagnosis of Burkitt lymphoma was made by typical "starry-sky" appearance in HE stain and immunohistochemical findings according to the World Health Organization classification of tumors of lymphoid tissues [20]. Although most of the cases of BL have c-myc translocations, up to 10% of cases may be c-myc negative. In about 80% of cases the translocation is between c-myc and the IgH genes, and in the remaining 20% the translocation is between c-myc and the non-IgH genes [21]. In our patient, FISH analysis showed that c-myc/IgH fusion probe was negative but c-myc apart probe was positive for the tumor cells, which implies the translocation is between c-myc and some non-IgH genes.
Intensive short-course chemotherapy combining with intrathecal injection regimen was recommend to treat systemic BL [22], whereas for PCNSL, the high-dose MTX-based chemotherapy regimen has been commonly used, which improves median disease-free and overall survival of up to 30 to 40 months from the survival of 12 to 18 months usually seen after using cranial radiotherapy (CRT) alone [23]. Some studies use CRT plus high-dose MTX as first-line therapy [24], but more researches recommend CRT after some form of initial chemotherapy, especially to patients older than 60 years. Moreover, a pediatric series of PCNSL has reported that immunocompetent and immunodeficient children with PCNSL may be cured with chemotherapy alone without CRT [25]. So the role and the timing of CRT are intriguing yet controversial.
Our patient had an isolated brain mass <3.5 cm in diameter at the age of 14 years and his spinal MRI and CSF cytology were negative. Thus we used gamma-knife therapy instead of CRT to decrease the risk of CRT-related neuropsychological sequelae [26]. During the whole 6 cycles of chemotherapy, no grade 2 or higher toxicities were found. Up to now, the tumor has been in complete remission for 18 months and our patient is attending school with no problems.
In summary, PCNSBL is a rare type of non-Hodgkin lymphoma, which has no specific clinical manifestations and imaging features. Treatment is still controversial. Our case report demonstrates that for isolated PCNSBL cases without spread to cerebrospinal fluid, the combination therapy of surgery, gamma-knife, and high-dose MTX-based protocol without intrathecal injection is effective and acceptable for children. This strategy reduced the risk of CRT and intrathecal injection and need to be studied for more details.

Declaration of Interest
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.