Abstract Background: Kaposi’s sarcoma (KS) is an angioproliferative neoplastic disorder that occurs in different epidemiological forms. Human Herpesvirus type 8 (HHV-8) is established as a causative agent of KS that has been mentioned in textbooks and literature. In the last two decades, KS cases were up searched through many Iraqi medical researches which have been published, but unfortunately, none of which had confirmed this association. Objectives: To assess the association of latent nuclear antigen-1(LANA-1) of HHV-8 among KS patients with clinicopathological parameters and to evaluate if this procedure is valuable for diagnosing this disease through the first immunohistochemical study in Iraq. Methods: This is a clinico-immunohistochemical descriptive study conducted at the Dermatology Center/Medical City, Baghdad, Iraq. Thirty-two KS cases diagnosed by clinical and histopathological means in the Dermatology/Pathology Departments /Medical City and three Private Medical Laboratories were studied from the first of January 2016 to the first of October 2022. Retrospectively, 20 KS cases with clinical and histopathological data were extracted from a patient’s registry while the remaining 12 cases were collected prospectively. All clinical and sociodemographic data were recorded then immuno-histopathological evaluations were done for them. Results: The most common type of KS was classical 27(84%) of cases followed by iatrogenic 4(13%) and HIV-associated 1(3%) case. Histomorphologically, 15(46.9%) of the cases were in the plaque stage, 11(34.3%) nodular stage and 6(18.8%) patch stage. The overall HHV-8 expression was detected in 27(84.4%) of the cases. The total histoscore was calculated by combining the staining intensity score and positive cell percentage score and shows a significant correlation with the stage of progression (P=0.02). No significant associations between HHV-8 expression and age, sex, disease recurrence, site of biopsy, and clinical types while the association with the disease duration was significant (P=0.032). Conclusions: Immunohistochemistry for HHV-8 is a sensitive and specific diagnostic method for KS. The majority of cases that did not express HHV-8 staining were in the early patch stages, with a relatively lower median duration than that of HHV-8 positive cases. Negative immunostaining for HHV-8 does not necessarily exclude KS in an appropriate clinicopathological setting.
