Oral Kaposi's sarcoma in Tanzania: presentation, immunopathology and human herpesvirus-8 association.

Oral Kaposi's sarcoma (OKS) from Tanzanian patients (78) at Muhimbili National Hospital/Muhimbili University College of Health Sciences corresponding to approximately 10% of KS registered during 1990-2005, were diagnosed (ELISA) as HIV-infected (OAKS) (74/78) and endemic KS (4/78). Females were 69.2% (54/78) with median age 31 and males 30.8% (24/78) with median age 38. More males (50%) had systemic KS than females (37%) and 4-times more multicentric OKS. All tested (34) oral KS patients sera had HHV-8 antibodies. Available (31/78) blood showed very low CD4+ T-lymphocyte counts. Most OKS (61.5%) had nodular histology. Immunostaining showed adult male nodular OAKS to have a significantly higher frequency of viral LANA+, endothelial CD34+ tumour spindle-cells (SC) and more Ki-67+ (median =24.1%) proliferating cells compared to females (17.2%). Juvenile nodular OAKS had more LANA+ and Ki-67+ cells than corresponding adult cases. Significantly more LANA+ and Ki-67+ cells were found in nodular OAKS compared to cutaneous HIV/AIDS Kaposi's sarcoma (CAKS). A positive correlation (60%) was found between the proliferation index (Ki-67+ cell frequency) and LANA+/CD34+ SC. OKS in Tanzania is since 1990, mostly seen in females, associated with HIV/AIDS and advanced (nodular) histopathology. Males have more systemic tumour burden while more females develop primary OAKS. HHV-8+ cells were more frequent in nodular male than female and in juvenile than adult nodular OAKS than cAKS. Higher tumoral HHV-8 content appeared to be correlated to proliferation index.