Magister Chirurgiae Dentium (MChD) / MChD (Oral Pathology) minithesis, Department of Oral and Maxillofacial Pathology, Faculty of Dentistry, University of Western Cape Among malignant lesions, lymphoma ranks second only to squamous cell carcinoma in frequency of occurrence in the head and neck. Lymphomas in HIV patients' are second in frequency to Kaposi's sarcoma as AIDS-defining tumours. About 50% of lymphomas in HIV patients are extranodal and more than half of these occur in the head and neck area. The number, variety and diagnostic complexity of lymphoma cases that have primarily arisen in the head and neck region has steadily increased in the surgical pathology service of the National Health Laboratory Services (NHLS) - Tygerberg. This observation is particularly relevant in the context of increasing HIV infection rates in the population of South Africa as demonstrated by a study in 2006 conducted by the Medical Research Council of South Africa. This is a retrospective study using the records of cases of head and neck lymphomas diagnosed at NHLS-Tygerberg over the last five years. The aim of this study is to investigate the prevalence of head and neck lymphomas (HNL) at NHLS-Tygerberg from January 2002 to December 2006. The objective of this study is to determine the frequency and types of HNL and to determine, if possible, an association between the incidence of HNL and the HIV status of the patients. Trends of prevalence in terms of gender, referral centres, HIV status, age of patients and site of presentation are also examined. The results of this study show an increase in the number of patients with HNL from January 2002 to December 2006. A significant increase is noted in the number of HIV positive patients documented each year, from 17% in 2002 to 33% in 2006. Western Cape- urban (WC-U) remains the largest referral center. A notable increase is seen, each year, in the number of patients referred to Tygerberg-NHLS from the Eastern Cape (EC) and Western Cape- rural (WC-R) areas. A significant number of HIV positive patients are referred from the Eastern Cape and Western Cape rural areas. The average age of disease presentation in the HIV positive group of patients is 35 years with the unknown group being 46 years and the HIV negative group being 54 years. The main categories of lymphoma that presented in HIV positive patients are plasmablastic lymphoma (PBL) and diffuse large B-celllymphoma (DLBCL), which together form 56% of cases. 26% of cases are Hodgkin's lymphoma (HL); the second largest group of HNL cases. Burkitt's lymphoma (BL) consists of 8% of cases. 7% of cases are T-cell lymphomas. 3% of cases are Mantle zone lymphomas. No cases of SLL and Follicular lymphomas (FL) are described in this group of patients. DLBCL and HL form 27% each of the cases in patients with a negative HIV status. A significant number of Follicular lymphomas (15%), small lymphocytic lymphoma (SLL) (9%), MALT (7%), and T-cell lymphomas (8%) are identified. No PBL are seen in this group of patients. The incidence of HNL at NHLS-Tygerberg has increased over the last five years. This trend parallels that seen in other developing countries such as Tanzania, Nigeria, Thailand and India. This increase is possibly due to an increase in the number of referrals to our center, an increase in the overall population of the Western Cape, an increase in the number of HIV positive patients and the high incidence of EBV infection in the general population of the Western Cape. Social issues, such as poverty, lack of adequate education, female dependence on partners, rural communities and the non-availability of anti-retroviral drugs (ARV) and highly active anti-retroviral therapy (HAART) to most of the population that require these drugs, are considered major contributing factors. A trend is noted in the increased number of female patients diagnosed each year with HNL. A predominance of DLBCL was identified in our series. This is consistent with previous reports and studies on HNL. The number of biologically aggressive lymphomas, such as DLBCL, Plasmablastic and Burkitt's lymphomas diagnosed each year, has also significantly increased. These were prevalent mainly in the HIV positive group of patients who were also younger compared to the HIV negative patients. The documented findings of this study will serve as a guideline for the estimation of head & neck lymphoma burden and risk assessment at NHLS- Tygerberg.