DISCUSSION
Lymphoid neoplasm encompasses group of white cell neoplasm varying in
clinical presentation and behavior; Leukemias arising in bone
marrow and circulating peripheral blood, lymphomas appearing as
tumour masses from lymph nodes or other organs and plasma cell
dyscrasias composed predominantly of plasma cells. Sometimes,
distinction between these clinical categories of lymphoid neoplasia is
difficult.6
Lymphomas are divided into two major group; Hodgkin and Non-Hodgkin
lymphoma. The non-Hodgkin lymphomas are further sub-divided into B-cell
and T-cell lymphomas. Burkitt’s Lymphoma belongs to peripheral B cell
neoplasm.7 There are 3 different types of BL: endemic
(African) form, the sporadic (non-African) form and
immunodeficiency-linked variety. The endemic form, which is the most
prevalent worldwide; affects younger children (4 to 7 years) involving
the head and neck (maxilla and mandible involvement in 58%).
Concomitant (endemic) malaria (or other infections) impairs immune
competence; allowing sustained B cell proliferation commonly seen in
this variant.8 Symptoms include cervical
lymphadenopathy, swelling of the jaw or facial mass, proptosis, teeth
mobility, paresthesia, and pain.9 Sporadic Burkitt’s
lymphoma (usually seen in European populations) shows gastrointestinal
involvement (56% of the cases) and is found more often in older
children(male> female). Both endemic and Sporadic Burkitt’s
lymphoma rarely arises in the lymph nodes. Immunodeficiency associated
Burkitt lymphoma is frequently seen in AIDS patients and patients on
immunosuppressive drugs following organ transplantation and can be found
in extra-nodal sites; abdomen being common site. Abdominal pain,
vomiting, bowel obstruction and gastrointestinal bleeding constitutes
the usual clinical presentation.10
Manifestations of BL are variable depending on the site of involvement
and the extension toward the adjacent structures. Sometimes, systemic
symptoms such as fever, weight loss, and headache might be
seen.11 Rapid progression of symptoms can be seen that
can even reach 24 to 48 hours. 9 Our patient mainly
presented with sore throat and foreign body sensation in the throat that
was attributed to the oropharyngeal extension. In fact, symptoms in
oropharyngeal BL are not specific to this entity and can delay the
diagnosis, since BL mainly manifests with cervical lymphadenopathy.
Physical examination findings can also be misleading as oropharyngeal BL
typically presents as a polypoid mass resembling other tumorous
condition.9
Although the diagnosis of BL is confirmed pathologically, multimodality
imaging approach imaging plays a critical role throughout the clinical
course from diagnosis to follow up imaging.12According to the National Comprehensive Cancer Network (NCCN)
guidelines, initial staging should be performed with cervical and
abdominal ultrasound, CT of the chest, abdomen, and pelvis. Depending on
the clinical presentation, contrast-enhanced neck and/or brain MRI may
also be done.12 CT scan is a crucial to assess tumor
localization, staging of the disease and post-treatment monitoring.
Currently, Gadolinium enhanced MRI is also the best imaging modality for
confirming oropharyngeal location, extension, its relationship to the
adjacent structures, and follow-up of BL. Compared with CT, MR imaging
can demonstrate homogenously enhancing mass with isointense signal on
T1-weighted images and an iso or hyper-intense signal on T2-weighted
images due to the cellularity and tends to infiltrate surrounding
structures without their destruction, especially in sporadic forms. In
contrast, endemic variants are characterized by osteolytic bone lesion
with destruction of maxilla-facial bones with an enlargement and
invasion of the adjacent structures.13 Our patient
also presented as an infiltrating homogenous mass with a hypo-intense
signal on T2-weighted images. However, CT and MRI findings are not
specific to this entity, and their findings can mimic other aggressive
diseases of the oropharynx.
Role of diffusion weighted imaging (DWI) and ADC value in BL is still
under study. Positron emission tomography (PET), when combined with CT,
offers the advantage of combining functional information with anatomic
imaging.14An increasing amount of research is being
done to assess the value of PET/CT in patients with BL and should be
performed if possible, provided it will not delay
treatment.12
Biopsy, immunohistochemistry and genetic analysis are other tests
helpful to get correct diagnosis. All variants of Burkitt lymphoma share
the same morphology and it is almost impossible to differentiate these
three variants on microscopic features alone. They are strongly
associated with translocations involving the MYC oncogene on
chromosome 8. Histopathology, BL typically has characteristic starry-sky
pattern. However, immunohistochemistry is a useful method for
identifying particular tumor cells that includes expression of CD20,
CD10, and bcl-6, Ki-67 proliferation rate.15
Bone marrow, Cerebrospinal fluid, Lactate Dehydrogenase Level, HIV and
Epstein-Barr Virus serology may also be required.16EBV exhibits strong tropism for B cells and infects them, causing them
to proliferate. In our case, the patient had positive antibodies for
Epstein–Barr virus. Virtually all cases of endemic BL carry EBV genome
whereas < 30% of sporadic and immunosuppression‑associated
variant are associated with this EBV virus. 17
The definitive treatment of BL is often based on the patient’s age and
the location of tumor. Different modalities such as surgery,
radiotherapy, chemotherapy, and radioimmunotherapy have been used to
treat Burkitt’s lymphoma, but systemic chemotherapy is mainstay of
treatment. BL dramatically responds to chemotherapies that includes
cyclophosphamide, vincristine, methotrexate, and prednisone causing
regressions of tumor and often lead to long-term
remission.18 Our patient was also placed under complex
chemotherapy resulting in the regression of the mass confirmed on
post-therapeutic imaging.
The role of surgery in BL is still controversial. Surgical treatment is
generally not required unless disease complications require prompt
surgical intervention such as in cases of bowel obstruction, optic nerve
decompression and airway obstruction.19
Prognosis depends on the stage of the disease at presentation, age of
patient, chemotherapy, lactate dehydrogenase levels and the association
with HIV. Patients who receive an early treatment are associated with
better outcomes in comparison to the delayed treatment which can cause
BL to reach other distant organs.20 Patients with
relapsed disease usually present symptomatically and within the first
year after the completion of treatment. Relapsed disease may occur at
the sites of original presentation or remotely. 12