Histopathological Aspects of Cutaneous Leishmaniasis due to Leishmania-Major in Libya

Aims: To describes the histopathological characteristics of skin lesions from patients with cutaneous leishmaniasis caused by Leishmania major in northwestern Libya and correlate with clinical presentation.

Study Design: case series study.

Place and Duration of Study: This study was carried on patients referred by the region's healthcare institutions and those presented at the Tripoli Central Hospital or the Libyan National Centre for Disease Control between July 2017 to January 2018.

Methodology: The study included 38 patients, aged between 1-73 years, of both sexes, and came from 18 endemic areas in North-Western of Libya. The inclusion criteria were clinical symptoms and microscopic visualization of the parasite on a Giemsa-stained skin smear, in addition, clinical by the slit and smear technique, polymerase chain reaction for L. major. In addition, statistical analysis was conducted for the Histopathological examination.

Results: The study found that 36 (94%) of the cases studied were positive by the slit and smear technique, and 32 (88.9%) were positive by PCR for L. major. Five histopathological patterns were observed: (i) diffuse cellular reaction without necrosis (25%); (ii) diffuse cellular reaction with necrosis (31.3%); (iii) exudative and necrotic granulomatous reaction (25%); (iv) exudative granulomatous reaction without necrosis (9.3%); (v) exudative-tuberculoid reaction with typical tuberculoid granuloma (organized) (9.3%). Inflammatory cellular infiltration ranged from mild to severe. Lymph plasmacytosis and lymph histiocytosis were predominant (34.4% and 21.7%, respectively). Necrosis was diffuse or local. The clinical features were correlated with this histological pattern. Epidermal changes included acanthosis, exocytosis, spongiosis, hyperkeratosis, and atrophy.

Conclusion: The histopathological changes observed in CL caused by L. major in North-Western of Libya are characterized by an intense diffuse inflammatory reaction in the dermis with the predominance of lymphoplasmacytic infiltration. Overall, the granulomatous presentation was the main one. Various clinical forms, including papule, plaque, erythematous nodule with hemorrhagic crust, or violaceous nodule with adherent crust and ulcerated nodule, are significantly correlated with the histopathological stages, whereas disease progression could be related to age. The histopathological diagnosis of CL caused by L. major has a sensitivity of 78% relative to PCR.