Detection of Leishmania DNA in paraffin embedded specimens of chronic lupoid leishmaniasis using polymerase chain reaction

Background: Chronic lupoid leishmaniasis (CLL) is a chronic form of cutaneous leishmaniasis that is usually resistant to anti leishmania agents and leishmania is not seen in the histologic sections. We used polymerase chain reaction (PCR) to detect leishmania DNA in CLL specimens. Method: This descriptive cross sectional study was done on 20 paraffin embedded specimens of CLL cases referred to the dermatology clinic of Imam Reza Hospital, Mashhad, Iran. Patients’ information including age, sex, duration and location of the lesion was obtained and then skin specimens were reviewed histopathologically and assessed for leishmania DNA using PCR. Result: Eleven male and 9 female patients with a mean age of 17.95 years were included in our study. The mean duration of lesions was 3.69 years. Most of the lesions (18 of 20 cases) were located on the face and others were on the limbs. Histologic study showed tuberculoid granulomatous inflammation with a variable ratio of histiocytes and lymphocytes without detection of leishman body. PCR was positive in 12 cases (60% of cases). We could not find any correlation between the results of PCR and sex,age, duration and location of the lesions. Histiocyte- prominent lesions were more prone to be positive on PCR examination but that was not statistically significant. Conclusion: Despite the very high sensitivity of PCR for the diagnosis of usual forms of cutaneous leishmaniasis, it fails to detect leishmania in a remarkable proportion of CLL specimens.