Role of Leishmania spp. infestation in nondiagnostic cutaneous granulomatous lesions: report of a series of patients from a Western Mediterranean area

Summary Background Leishmaniasis is a parasitic disease prevalent in countries of the Mediterranean area. Objectives The potential role of Leishmania as the aetiological factor for cutaneous granulomatous lesions in a series of patients from a Western Mediterranean area was evaluated. The practical usefulness of Leishmania‐specific polymerase chain reaction (PCR) amplification and immunohistochemical techniques in skin biopsy specimens was assessed. Methods Twenty‐five skin biopsies diagnosed as nonspecific granulomatous dermatoses were included in the study. A panel of histopathological features was blindly evaluated by two independent observers. Only those cases showing nondiagnostic clinicopathological features and lacking demonstrable microorganisms after bacteriological, mycological or mycobacteriological cultures and specific stains (Ziehl–Neelsen, Giemsa, Gram, periodic acid–Schiff stains) were finally selected. Quantitative real‐time PCR was performed in all selected samples. In available samples, immunohistochemical detection of specific Leishmania spp. antigens was also performed. Results From the selected 25 biopsies, Leishmania spp. DNA was detected by real‐time PCR in 13 cases. In seven of eight PCR‐positive cases the presence of a varying density of amastigotes could also be demonstrated immunohistochemically. Conclusions Leishmania infection seems to be an important aetiological factor in cutaneous granulomatous lesions showing nondiagnostic features in endemic areas. In such areas, Leishmania‐specific PCR amplification and/or immunohistochemical studies may be useful diagnostic tools. These techniques may be specifically indicated in the evaluation of patients showing nonspecific granulomatous inflammatory infiltrates of unknown aetiology lacking the histopathological evidence of parasites.