Accuracy of Clinical suspicion and pathologic diagnosis of Kaposi Sarcoma in East Africa

Abstract

Background: HIV-associated Kaposi sarcoma (KS) is one of the most common malignancies in sub-Saharan Africa. The diagnosis is often based on clinical suspicion, without histopathologic con fi rmation. When biopsies are performed, the accuracy of interpretation by local pathologists is poorly understood. We assessed the accuracy of clinical suspicion and pathologic diagno- sis of KS in 2 East African countries. Methods: At 2 large HIV care sites in Uganda and Kenya, we evaluated consecutive biopsies performed from October 2008 to January 2013 on HIV-infected adults with clinically suspected KS. Biopsies were interpreted by both local African pathologists and a group of US-based dermatopathologists from a high volume medical center. For the purpose of this analysis, the US-based dermatopathologist interpretation was used as the gold standard. Positive predictive value was used to characterize accuracy of local African clinical suspicion of KS, and concordance, sensitivity, and speci fi city were used to characterize accuracy of local pathologic diagnosis.Results: Among 1106 biopsies, the positive predictive value of clinical suspicion of KS was 77% (95% con fi dence interval: 74% to 79%). When KS was not histopathologically diagnosed, clinically banal conditions were found in 35%, medically signi fi cant disorders which required different therapy in 59% and life-threatening diseases in 6%. Concordance between African pathologists and US-based dermatopathologists was 69% (95% con fi dence interval: 66% to 72%). Sensitivity and speci fi city of African pathologic diagnoses were 68% and 89%, respectively. Conclusions: Among East African HIV-infected patients, we found suboptimal positive predictive value of clinical suspicion of KS and speci fi c, but not sensitive, histopathologic interpretation. The fi ndings call for abandonment of isolated clinical diagnosis of KS in the region and augmentation of local dermatopathologic services