Leishmaniasis pathology

Introduction

Leishmania is a organism related to trypanosomes. the inflammatory disease caused by the body that can affect the skin and mucous membranes as well as internal organs. The organism's life cycle contains a flagellated phase (promastigote) while it lives within the vector, and a phase when the flagellum retracts (amastigote), which is the stage seen in humans infection and visualized in tissue sections or smear preparations.

Histology leishmaniasis

There are three basic types of cutaneous leishmaniasis: cutaneous leishmaniasis (acute and chronic), mucocutaneous leishmaniasis and disseminated Anergic cutaneous leishmaniasis.

Depending on the clinical type and stage, in leishmaniasis, the epidermis can ulcerate with marked secondary changes and epidermal reaction, or alternatively, the epidermis can be quite inconspicuous and overlap with dense dermal infiltrate (Figure 1). The infiltrate is typically dense and contains predominantly histiocytes, lymphocytes and plasma cells (figure 2). Other acute inflammatory cells are generally difficult to find unless there is ulceration and minor changes. The infiltrate can surround neurovascular bundles similar to lepromatous leprosy.

Leishmania organisms they are typically easy to visualize in routine HE sections during the early stages of the disease and, similar to lepromatous leprosy, can be difficult to find late in the disease where there is resolution granulomatous and sclerotic inflammatory pattern In the early stages of leishmaniasis, many amastigotes tend to distend the histiocytes (Figure 3) and impart a fairly characteristic diagnosis. morphology.

Special spots for leishmaniasis.

Leishmania organisms are usually intensely positive with Giemsa staining, where they stain blue in paraffin-embedded sections. Smears of skin or other organs can also demonstrate the body with Giemsa staining. In difficult cases, or for precise characterization of organisms molecular techniques like Polymerase chain reaction (PCR) It can be applied.

Differential diagnosis leishmaniasis pathology

Histoplasmosis: Organisms are similar in size to Leishmania, but easily stain with silver spots, show narrow-based shoots and a halo of microorganisms.

Granulomatous disease: The later or granulomatous stages of leishmaniasis may resemble sarcoidosis or other granulomatous diseases. PCR-based methods can aid in diagnosis when organisms are scarce / impossible to visualize with hematoxylin and eosin (HE) and Giemsa stains