Conjunctival squamous cell carcinoma in Tanzania.

AIMS To assess changes in incidence of conjunctival squamous cell carcinoma over a 22 year period in Tanzania and to analyse possible reasons for change. METHODS Retrospective analysis of records from a Tanzanian pathology department serving north and central Tanzania from 1976 to 1997; medical record analysis of cases of conjunctival squamous cell carcinoma presenting in the last 2 years of the study. RESULTS There was a sharp rise in the incidence of conjunctival squamous cell carcinoma in the last 3 years of the study (1995-7). The mean age of patients presenting with the condition over the full period was 44.7 years (95% confidence interval 42.4-46.9 years). In the final 2 years of the study the mean length of history on presentation was 3.1 months (2.1-4.0 months). Several patients had a previous history of chronic conjunctival disease such as allergic conjunctivitis and trachoma; one had had a conjunctival papilloma excised previously. Only five patients had been tested for HIV status, but of these four were positive. CONCLUSION Tanzania is experiencing an epidemic of conjunctival squamous cell carcinoma similar to that seen in other African countries. Often the tumours are aggressive and occur in patients of relatively young age. The epidemic appears to be related to HIV infection, on a background of ultraviolet light exposure. Previous chronic conjunctival disease and exposure to human papillomavirus may also have a role.