Accuracy of Clinical Suspicion and Pathologic Diagnosis of Kaposi Sarcoma in East Africa.
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 confirmation. When biopsies are performed, the accuracy of interpretation by local pathologists is poorly understood. We assessed the accuracy of clinical suspicion and pathologic diagnosis of KS in two East African countries.
At two large HIV care sites in Uganda and Kenya, we evaluated consecutive biopsies performed from October 2008 to January 2013 upon HIV-infected adults with clinically suspected KS. Biopsies were interpreted by both local African pathologists and a group of U.S.-based dermatopathologists from a high volume medical center. For the purpose of this analysis, the U.S.-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 specificity were used to characterize accuracy of local pathologic diagnosis.
Among 1106 biopsies, the positive predictive value of clinical suspicion of KS was 77% (95% CI: 74%-79%). When KS was not histopathologically diagnosed, clinically banal conditions were found in 35%, medically significant disorders which required different therapy in 59%, and life-threatening diseases in 6%. Concordance between African pathologists and U.S.-based dermatopathologists was 69% (95% CI: 66%-72%). Sensitivity and specificity of African pathologic diagnoses were 68% and 89%, respectively.
Among East African HIV-infected patients, we found suboptimal positive predictive value of clinical suspicion of KS and specific, but not sensitive, histopathologic interpretation. The findings call for abandonment of isolated clinical diagnosis of KS in the region as well as augmentation of local dermatopathologic services.
Amerson E, Woodruff CM, Forrestel A, Wenger M, McCalmont T, LeBoit P, Maurer T, Laker-Oketta M, Muyindike W, Bwana M, et al. Accuracy of Clinical Suspicion and Pathologic Diagnosis of Kaposi Sarcoma in East Africa. J Acquir Immune Defic Syndr. 2015 Oct 8. [Epub ahead of print] PubMed PMID: 26452066.