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 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. Methods 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. Results 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. Conclusions 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.

A decade of HIV care in rural Tanzania: Trends in clinical outcomes and impact of clinic optimisation in an open, prospective cohort

“…Our observed prevalence in 2014 of 5% is consistent with other studies (3–7.1% [30]). While globally the incidence of Kaposi sarcoma is decreasing with increasing ART coverage [31,32], we observed increasing prevalence over time, reaching 3.6% among patients enrolled in 2014 with low CD4 count, most likely due to improved detection, although the limitations of physician-diagnosis are known [33]. Among the same KIULARCO patients, PCP prevalence was lower than in a recent meta-analysis of studies conducted between 1995 and 2015 (5.8% versus 15.4%) but the authors found substantial heterogeneity by time, clinical setting and diagnostic method [34].…”

Diagnosis and Treatment of Kaposi Sarcoma

“…Although KS can be strongly suspected in an appropriate clinical setting, recent studies confirmed the limited predictive value of clinical diagnosis of KS [55]. Histopathological confirmation of a diagnosis of KS remains the gold standard, but the diagnosis is often not straight forward, especially if pathologists are not familiar with the spectrum of histopathological features of KS.…”

HIV-associated malignancies in sub-Saharan Africa

“…Diagnostic pathology in SSA is also limited, and often under-utilized when it exists [9]. Even for superficial tumors which can be visualized and often are diagnosed clinically in SSA, like Kaposi sarcoma (KS) and ocular surface squamous neoplasia (OSSN), clinical diagnosis performs poorly compared to pathology with positive predictive value less than 80% [10*, 11*]. For more visceral tumors, not only pathology limitations but inadequate surgical or interventional capabilities to obtain diagnostic tissue results in these tumors also being underrepresented.…”