Clinical, histopathologic, and immunohistochemical patterns of cutaneous leishmaniasis

Leishmaniasis is an intracellular parasitic infection whose life cycle involves two different hosts: a female sandfly and mammals (including humans and dogs). The initial lesion develops after the bite of an infected sandfly. Usually, it is a solitary papule that ulcerates with a raised border. We describe four cases with clinical manifestations, histopathological/immunohistochemical patterns, and outcomes. All biopsies were stained with hematoxylin and eosin, Giemsa, Grocott methenamine silver, periodic acid-Schiff, Gram, and acid-fast bacillus and submitted for polymerase chain reaction (PCR). The patients' mean age at diagnosis was 35 years; all were men who had immigrated to the United States by walking through the Amazon jungle in South America. Microscopy revealed a mixed infiltrate in the dermis. Amastigotes were visible in histiocytes and vacuoles and were highlighted by the Giemsa stain. The lesions were successfully treated with amphotericin B for seven days in four patients; the fourth was lost to followup. The diagnosis of cutaneous leishmaniasis was made based on clinical presentation, biopsy, and PCR results, when available. Leishmaniasis is a major public health problem. Globally, it is among the top 10 neglected tropical diseases, with >12 million people infected worldwide. Leishmania is a protozoan parasite transmitted by female sandflies that creates a neglected tropical disease according to the World Health Organization. It is a major public concern due to its consequences on health, especially in people with socioeconomic difficulties. There are three main clinical forms: (1) localized cutaneous leishmaniasis (CL); (2) mucocutaneus leishmaniasis; and (3) visceral leishmaniasis. The eight countries contributing to 90% of the cases are Afghanistan, Algeria, Brazil, Iran, Pakistan, Peru, Saudi Arabia, and Syria.¹.