Sometime in 2008, some of us were invited to a workshop under the auspices of the World Health Organisation (WHO) and Centre for Disease Control on a pilot scheme to develop a document for the training of trainers of those involved in anti-retroviral therapy. The venue was Kaduna. Before this, a template of the document had been prepared and the purpose was for those who were not involved in the preparation of the template to come as participants and possibly make inputs where necessary.
During one of the plenary sessions, yours truly had pointed out that Burkitt’s lymphoma was in nowhere mentioned in the document as a possible sequel of the human immunodeficiency virus (HIV) infection. One of the facilitators had looked up thoughtfully and simply dismissed the question that they considered Burkitt’s as a Malaria ‘thing.’ Some of us wondered how could that be, or perchance they never thought of it. The logic was simple: chronic malaria leads to compromise of the immune system and with secondary infection by Epstein – Barr virus – Burkitt’s lymphoma is the ultimate jaw tumour in children. And by the way what is HIV doing in the body as the name depicts?
Today, not only is immunodeficiency associated Burkitt’s lymphoma documented, it is also now a sub-classification.
Dennis Parsons Burkitt was an Irish-born surgeon who, in 1958, described a unique jaw tumour that was prevalent among children in Uganda. He had also taken time to write to some of his colleagues about this experience. He proceeded to do detailed documentation of this rapidly growing tumour whose response to chemotherapy was also almost magical. The tumour, derived from the B cells of lymphocytes, was to be named after him, hence the name Burkitt’s lymphoma.
In life, red blood cells do not get in contact with other cells of the body. They remain in the conveying vessels, be they arteries or tiny capillaries. All the cells in the body are awash with extra vascular fluids, which are filtrates from the vascular compartment. These fluids, in some compartments, are known as LYMPH. They constitute what is aptly described as lymphatic system of drainage, which ultimately finds themselves in the large veins for recycling. The lymphatic system is populated by cells known as LYMPHOCYTES, whose main function is to identify foreign bodies known as antigens and set up the mechanism to destroy them, by producing antibodies. There are two types of lymphocytes, B and T cells.
Burkitt’s lymphoma is cancer of the lymphatic system, especially B lymphocytes that are found in the secondary organs germinal centre. For clarity, lymphocytes are primarily produced in the thymus gland and bone marrow, just like any other blood cell; but in life migrate to populate what are often referred to as secondary organs, which include tonsil, spleen, lymph nodes and Peyer’s patches found in the digestive tracts. It is in these organs that lymphocytes proliferate, undergo mutations and carry out their immunological or rather defense functions.
Currently, Burkitt’s lymphoma is classified into three main clinical variants: the endemic, the sporadic type and the immunodeficiency associated type! The endemic variant, which is also known as the African type is found in children living in malaria endemic region. This results from chronic malaria infection that reduces the resistance to Epstein-Barr virus, allowing it to overwhelm the lymphocytes, leading to a malignant change. The commonest site for this tumour is the jaw or facial bones. It could also affect the abdomen and other distant organs.
The sporadic or non-African type is found in regions where malaria is not HALOENDEMIC. It is also not associated with Epstein –Barr virus and the jaw is not a common site for the lesion. It is mainly an abdominal malignancy. The immunodeficiency associated Burkitt’s lymphoma is commonly linked to the human immunodeficiency virus (HIV) infection and could actually be the initial manifestation of Acquired Immunodeficiency Syndrome (AIDS) if the diagnosis was missed earlier. This can also occur in a patient who had organ transplant and on immunosuppressive drugs intended to prevent rejection.
The diagnosis of Burkitt’s lymphoma usually does not pose much of a challenge. In the very early stage, the onus usually is at the doorstep of the dentist and the maxillofacial surgeon. The first thing that he may notice on the patient being sent to him is the scattering or rather derangement of the teeth in x-rays of the jaw and oral cavity. This is often described as dental anarchy. In a lot of cases, this may be diagnostic. But the real clincher is the appearance of stained slide during histological examination.
Under low power microscopy, the background field is populated with medium sized lymphocytes with features in keeping with rapid cell division and degeneration. The lymphocytes are stained blue.
This background is interspaced with large phagocytes cells known as MACROPHAGES containing engulfed tumour cells. Their appearance is almost colourless; and when viewed from a distance gives an impression of a blue sky with stars, hence the description ‘starry sky’ appearance. At this stage in most cases, the evidence of malignancy and distant spread known as metastasis are usually pronounced
The response to anti-cancer drugs in itself can be diagnostic. Rapidly growing tumours respond faster to chemotherapy than slow growing lymphomas. In remote areas where standard laboratories are not available, therapeutic trials have proved useful even in confirming the diagnosis of Burkitt’s where there is a high index of suspicion. Following this good response to drugs, three core factors must always be at the back of the minds of caregivers: the nutritional status, sepsis and above all what is often referred to as tumour lysis syndrome. Simply put, when cells are rapidly destroyed, some of the ions that are normally intracellular (domiciled inside the cells) like POTASSIUM and other bi-products of cell degradation are poured into the general system and can be hazardous if not rapidly excreted.
By and large, with efforts being made to roll back malaria and aggressive pursuant of prevention of mother to child transmission (PMTCT) of human immunodeficiency virus infection, the prevalence of Burkitt’s lymphoma is not as it was in the 70s and 80s of the last century. During that period if asked to classify lymphomas in this part of the world, a medical student would tell you; Burkitt’s and non-Burkitt and under non-Burkitt’s you had Hodgkin’s and non-Hodgkin lymphoma. In most textbooks that period it was the other way round. The story these days about Burkitt is not as gory as it used to be. Perhaps, Burkitt is gradually taking the back seat.