Investigation of human herpesvirus 8 & Leishmania species in malignant skin tumours, psoriasis, actinic keratoses, & seborrheic keratoses: A single-center experience from Ankara, Turkey

Background & objectives The role of human herpesvirus-8 (HHV-8) and Leishmania species in the aetiology of malignant skin tumours and proliferative skin diseases remains a topic of debate. This study aims to analyse formalin-fixed, paraffin-embedded (FFPE) skin biopsy samples using polymerase chain reaction (PCR) to determine whether skin lesions caused by HHV-8 and Leishmania spp. resemble malignant and proliferative skin diseases and assess the role of these pathogens in disease aetiology. Methods In this retrospective, single-center observational study, skin biopsies were collected from 275 individuals diagnosed with malignant skin tumours, psoriasis, actinic keratoses, seborrheic keratoses, and chronic dermatitis. The presence of HHV-8 and Leishmania spp. in biopsy samples was evaluated using PCR. Results HHV-8 DNA was not detected in any of the samples using PCR. However, Leishmania spp. DNA was identified in 8.4 per cent of all samples (n=23). No positivity was observed in the control group (P=0.387). Leishmania spp. DNA PCR positivity was most frequently detected in psoriasis cases (32.4%), followed by actinic keratosis (AK) (8.7%), malignant skin tumours (4.2%), and seborrheic keratosis (SK) (3.8%). When the Leishmania positivity rate in individuals diagnosed with psoriasis was compared with that of the control group, the difference was found to be significant (P=0.002). The positivity rate in squamous cell carcinoma (SCC) (7.3%) was higher than in basal cell carcinoma (1.6%). Interpretation & conclusions The findings in this study suggests that there is no relationship between malignant and proliferative skin diseases and HHV-8. However, Leishmania spp. DNA was detected in 8.4 per cent of all samples. Biopsy-archived samples may be preferred for the differential diagnosis of Leishmania in diseases that do not respond to treatment and in atypical clinical presentations.