Gastrointestinal tract (GI-tract) is one of the most commonly affected sites of extranodal non-Hodgkin lymphoma (NHL)(10). Secondary gastrointestinal involvement in lymphoma is more common, primary gastrointestinal lymphoma is rare(2). BL in all the pathological types is infrequent. Primary BL of stomach is rare. Primary gastric BL in adults has been reported by Mitra S, Khan A, Doycheva I et.al(2, 9, 11, 12). Their study showed that the ratio of male patients is higher than female. Chlidren cases have been reported by Angotti R, Kim SC et.al(13, 14). A retrospective analysis showed that gastric BL often involves body and antrum of stomach(15). BL is a highly malignant B-cell non-Hodgkin lymphoma characterized by rapid proliferation. Growth rate of BL is almost 100%, it only takes 25 hours to double in number(3, 16). According to WHO classification, 3 clinical variants of BL are described: endemic, sporadic, and immunodeficiency-associated types(4). And the distinction of the two subtypes, EBV-positive BL vs. EBV-negative BL, is recommended by the WHO-HAEM5. The latest insight is that it is possible that EBV is closely related to BL pathogenesis, such as affecting mutations(17). Endemic type is common in African children, the ratio of men to women is 2:1(8, 18). This type is closely associated with EBV, and it is often found as a jaw or periorbital mass(5, 16). Sporadic type is common in children in America and Europe. The clinical manifestation of this type is abdominal symptom, such as abdominal mass, intestinal obstruction or intussusception and abdominal pain(3, 16). In our reported case, the patient began with upper abdominal distension and physical examination revealed an abdominal mass. That's consistent with sporadic type characteristic. Immunodeficiency-associated type is common in HIV-infected individuals and
patients’ CD4 counts always exceeds 200 cells/µL(3, 19). These two types usually affect extranodal sites (such as bone marrow and GI-tract) and CNS (especially the pia mater)(20, 21). According to previous case reports, most patients with gastric BL have mild symptoms even though lesions of the stomach are serious(11, 13, 14). But the disease can progress very quickly and some serious symptoms appear, such as gastrointestinal bleeding and difficulty swallowing. Some patients die from progression of the disease(2, 12). LDH and uric acid can significantly increase in the early stages of the disease because the tumor load of BL is high(3). The lymph nodes, liver and spleen can be well showed by color ultrasound and CT(14). Exceptional hypermetabolic tissue functional status of the whole body can be accessed by PET-CT because BL has a high glyco-lytic rate(22, 23). Gastrointestinal endoscopy can intuitively show mass in GI-trcat and it can assess tumor infiltration well. Under endoscopy, gastric Burkitt's lymphoma is common in ulcerative lesions(2, 9, 11, 13, 14). And the ulcer surface is often covered with a large amount of mucus. Bone marrow biopsy and lumbar puncture with ce-rebrospinal fluid analysis are essential(18). Pathological findings are very important for diagnosis. Medium sized, round and uniform tumor cells is the cytological characteristic of BL and they have abundant cytoplasm(16, 18, 20, 24). Tumor cell debris contained within the phagocytic cells is distributed among the lymphocytes in basophilic cytoplasm background, which is called “starry sky” appearance(18, 20, 24, 25). This is the symbol of BL. The immunohistochemistry evaluation revealed that tumor cells are positive for CD10, CD19, CD20, CD22, Bcl-6, TCL − 1 and C-Myc and negative for CD3, CD5, Bcl-2, TDT and Cyclin D1. And Ki-67 proliferation index is often more than 95%(3, 24, 25). MYC gene translocation is the genetic characteristic of BL(26),
but it’s not specific to BL(27). Translocation between MYC gene in chromosome 8 and immune globulin heavy chain in chromosome 14 is the most common(3, 14, 25). MYC is a tumor gene which can promote cell growth and proliferation, and translocation between MYC gene and immune globulin heavy or light chain can result in MYC activation and overexpression(8). We evaluate this patient condition with the help of radiological, endoscopic, pathological, immunohistochemistry and genetic testing. The examination results suggested that the patient is primary gastric BL. It is worth noting that BL needs to be differentiated from gastric adenocarcinoma and other gastric lymphomas because they may have similar clinical manifestation, radiologic and endoscopic performance. Burkitt’s Lymphoma is highly sensitive to chemotherapy, many BL cases can be cured through intensified chemotherapy(8, 9, 14). CODOX-M/IVAC, Hyper-CVAD ( Hyperfractionated cyclophosphamide, vincristine, doxo-rubicin, dexamethasone alternating with high-dose methotrexate and cytarabine) and R-EPOCH (Rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxo-rubicin) are frequently-used chemotherapy regimens(8, 27). A retrospective analysis showed that there is no clear difference among these regimens(21). Rituximab as monoclonal antibody that antagonizes CD20 can improve prognosis because CD20 is significantly expressed in BL(2, 21, 28). The 5-year overall survival (OS) can achieve 75–85% through intensified chemotherapy combined with Rituximab. Intrathecal injection is important for preventing central nervous system infiltration because there is a 20–30% lifetime risk of CNS involvement(29, 30). The relapse rate decreased to 6–11% with this approach(30). Tumor lysis syndrome (TLS) may occur in the early stage of chemotherapy because of high proliferation rate of BL. TLS refers to a rapid and massive destruction of
tumor cells causing hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia. And it can cause acute renal failure(31). Treatment-related toxicity is another cause of death in therapy progress, and the most common toxicities consist of myelosuppression and infections(3). The patient that we reported received intensified combination chemotherapy and intrathecal injection. And treatment response was good. Although treatment-related toxicity occurred, he improved later. At the most recent review, the primary lesion was smaller than before. This suggests that there is hope for a cure for BL. Long-term treatment response needs to be observed. There is not a universal prognostic scoring system of BL now. Bone marrow and CNS involvement are main prognostic factors(21, 27, 28). Other prognostic factors include: age, performance status, level of LDH, Ann Arbor staging, exsis of extranodal disease and the black race(21, 27, 32). There may be some new treatments in the future, such as chimeric antigen receptor T-cell therapy and bispecific antibodies(8, 16, 32).
In conclusion, primary gastric Burkitt’s Lymphoma is a rare disorder that can be cured with timely diagnosis and treatment. We report clinical presentation, diagnosis and treatment response of a case of primary gastric BL. More studies are in need to explore the etiology, pathogenesis, treatment, and prognosis of this disease.