Burkits Lymphoma

BURKITS LYMPHOMA Definition It is a high-grade B-cell neoplasm and has 2 major forms, the endemic (African) form and the nonendemic (sporadic) form. Burkitt lymphoma is a childhood tumor but it is observed in adult patients. Burkitt lymphoma is one of the fastest growing malignancies in humans, with a very high growth fraction. Pathophysiology: Burkitt lymphoma is a monoclonal proliferation of B lymphocytes characterized by small noncleaved cells that are uniform in appearance and that produce a diffuse pattern of tissue involvement. -Under the microscope, Burkitt lymphoma is characterized by the presence of a "starry sky" appearance (also observed in other highly proliferative lymphomas), imparted by scattered macrophages with phagocytes cell debris. -The African form most often involves the maxilla or mandible. The involvement of abdominal organs, such as the kidneys, ovaries, or retroperitoneal structures, is slightly less common. In contrast, the sporadic form usually involves abdominal organs, with the most common involvement of the distal ileum, cecum, or mesentery and less common involvement of other abdominal organs, pelvic organs, and facial bones. Most Burkitt lymphomas carry a translocation of the c-myc oncogene from chromosome 8 to either the immunoglobulin (Ig) heavy-chain region on chromosome 14 [t(8;14)] or one of the light-chain loci on chromosome 2 (kappa light chain) [t(8;2)] or chromosome 22 (lambda light chain) [t(8;22)]. The Epstein-Barr virus (EBV) has been implicated strongly in the African form, while the relationship is less clear in the sporadic form. -EBV is associated with about 20% of sporadic cases. -Rare adult cases are associated with immunodeficiency, particularly AIDS. -The lymphocytes have receptors for EBV and are its specific target. -In the African form, the hosts are believed to be unable to mount an appropriate immune response to primary EBV infection, possibly because of coexistent malaria or another infection that is immunosuppressive. Months to years later, excessive B cell proliferation occurs

Epidemiology Burkitt lymphoma is endemic in certain regions of equatorial Africa and other tropical locations between latitudes 10° south and 10° north. Incidence in these areas of endemic disease is 100 per million children. Mortality/Morbidity: With combination chemotherapy and CNS prophylaxis, the survival rate is now at least 60%. Patients with limited disease have a survival rate of 90%. Patients with bone marrow and CNS involvement have a poor prognosis. Adults with the disease, especially those in the advanced stage, do more poorly than affected children. Sex: The male-to-female ratio is 2-3:1. Age: -Burkitt lymphoma is most common in children. In Africa, the mean age is 7 years. -Outside Africa, the mean age is 11 years. Clinical presentation History: In the African form  Most often present with swelling of the affected jaw other facial bones, loosening of the teeth  Swelling of the lymph nodes, which are nontender and rapidly growing, in the neck or below the jaw.  Abdominal presentation is slightly less common  Wt loss, Night sweat, generalized fatigue. Sporadic form  Abdominal tumors causing swelling and pain in the affected area.  Some patients present with symptoms of bowel obstruction secondary to an ileal-cecal intussusception caused by tumor growth. -Because of the rapid growth of the Burkitt tumor, patients may quickly manifest significant metabolic derangement and renal function impairment

)The most commonly used staging system for NHL

-Less common presentations of Burkitt lymphoma include an epidural mass, skin nodules, CNS symptoms, and bone marrow involvement. -Rare cases of Burkitt lymphoma can present as acute leukemia (L3-ALL) with fever, anemia, bleeding, and adenopathy. Physical: Major signs of Burkitt lymphoma include a soft tissue mass associated with the involvement of the jaw or other facial bones, enlarged cervical lymph nodes, abdominal masses, and ascites. Staging The most common system of staging for non-Hodgkin's lymphomas in adults, including Burkitt's lymphoma, is the Ann Arbor system. Stage I: - Limited to one group of lymph nodes either above or below the diaphragm, - Organ or part of the body other than the lymph nodes, but has not spread to other organs or lymph nodes. Stage II: - The lymphoma in two or more lymph node groups on the same side of the diaphragm - only one organ involved and has spread to the lymph nodes near that organ Stage III: - The lymphoma is present in groups of lymph nodes on both sides of the diaphragm. - It may involve an organ or site outside the lymph nodes, the spleen, or both. Stage IV: - The lymphoma is disseminated (spread) throughout one or more organs outside the lymph nodes. There may or may not be involvement of lymph nodes that are remote from the affected organs. For each of stages A -No general symptoms B- Is used for patients with any of the following:  Unexplained loss of more than 10% of body weight in the last six months  Unexplained fever  Drenching night sweats E - malignancies outside the lymph nodes Other sites in the body are identified with additional letters,

in children is that of the St. Jude's Children's Research Hospital. (Stage I) It separates patients with a single tumor or diseased lymph node (Stage II) or two or more tumors or diseased lymph nodes on the same side of the diaphragm (Stage III) from those with a large chest or abdominal tumor or (Stage IV) Involvement of the bone marrow and central nervous system Investigations Lab Studies: 1.FBC and ESR 2.Electrolytes-serum levels of sodium, potassium, calcium, phosphorus, magnesium 3.Urea, and creatinine 4.Uric acid levels 5.Liver function tests. 6.Biopsy of suspected lymph nodes or other disease sites, including bone marrow, is essential for the diagnosis. 7.FNA of the lymph node may also be done. 8.Cerebrospinal fluid (CSF) also should be evaluated in all cases. 8.Cytogenetic studies of peritoneal or pleural fluid, when appropriate, should be performed for diagnostic or staging purposes. Imaging Studies: 1. CXR -rule out lung metastasis and mediastinal involvement. Chest CT should be performed if chest x-ray is abnormal 2.Abdominal U/S 3. Abdominal CT scan -retroperitoneal and mesenteric lymph nodes, liver, kidneys, ovaries, and other structures. 4.Head or spinal CT scan or MRI is indicated if neurological signs and symptoms are present. 5.Bone scan and plain bone radiographs are needed for patients with symptoms of bone involvement.

such as D for the skin or H for the liver. Histologic Findings: Lymph node involvement occurs. Burkitt cells are homogeneous in size and shape, with round to oval nuclei and slightly coarse chromatin, with multiple nucleoli, and with intensely basophilic vacuolated cytoplasm that contains neutral fat. Frequent mitotic figures usually are observed. A starry sky appearance is imparted by scattered macrophages with phagocyte cell debris.