Histopatologia da forma localizada de leishmaniose cutânea por Leishmania (Leishmania) amazonensis

Abstract

The microscopic changes found in the localized form of the human cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis are reported. In this form, less known than the diffuse one caused by the same species, the clinical manifestations are identical to those produced by other Leishmania species of the subgenus Viannia. There is, however, in the localized infection by L. (L.) amazonensis, a peculiar feature, only recently discovered: about 50% of the affected individuals are Montenegro-negatives. The main histologic change observed in the skin sections was the presence of groups of macrophages with a large vacuole in the cytoplasm, containing many amastigotes. The microscopic picture is similar to that found in the diffuse form of the disease, the difference being only quantitative. When in large numbers, the macrophages suffers necrosis, which generally starts at the center of the groups. First, in this process, the membrane of the parasitized cells ruptures, and the amastigotes become free; later, both cells and parasites are destroyed. The picture can be seen either in Montenegro-negative or in Montenegro-positive patients. The macrophages with amastigotes may persist in tissues for as long as 6-7 months, while in the infections due to L. (V.) braziliensis the parasites usually disappear in a few weeks.

Clinical and immunopathological spectrum of American cutaneous leishmaniasis with special reference to the disease in Amazonian Brazil: a review

“…In patients with lesions due to L. (L.) amazonensis the nature of the lesion gives a clue as to the causative parasite, namely the large infiltration at the edge of lesion, and its histopathology. In these lesions there is a dense infiltrate of vacuolated macrophages in the dermis which are full of amastigotes and give the infiltrate the appearance of a macrophagic granuloma (Moraes & Silveira 1994). This differs from the histopathology in cases of LCL caused by L. (V.) braziliensis and other species of the subgenus Viannia, where there is a more modest infiltration in the skin bordering the ulcerated lesion, and in which macrophages and parasites are generally scanty: in contrast, lymphocytes and plasma cells are more frequent in the infiltrate, which has the characteristics of an epithelioid granuloma (Fig.…”

“…In older cases of the disease, disseminated lesions may cover much of the body, but are predominantly on the extremities and rarely involve the nasopharyngeal mucous membranes (Convit et al 1972, 1993, Barral et al 1995. In the dermis the histopathological feature is a severe infiltration of macrophages containing abundant amastigotes: lymphocytes and plasma cells are rare, giving the infiltration the aspect of a macrophagic granuloma (Bittencourt & Guimarães 1968, Silveira et al 1990, Bittencourt & Barral 1991, Moraes & Silveira 1994 (Fig.1h).…”

Further observations on clinical, histopathological, and immunological features of borderline disseminated cutaneous leishmaniasis caused by Leishmania (Leishmania) amazonensis

“…What led these authors to use this term was doubtless the negative Montenegro skin-tests of both patients together with a histopathology of the lesions showing an infiltrate composed principally of highly vacuolated macrophages containing abundant amastigotes. In the light of our present observations we would have referred to such infections as localized cutaneous leishmaniasis (LCL) (Moraes & Silveira 1994, Silveira et al 2004. Indications that some cases of cutaneous leishmaniasis due to L. (L.) amazonensis did not fit neatly into the categories of localized cutaneous leishmaniasis and anergic diffuse cutaneous leishmaniasis were noted by Lainson et al (1986) and Silveira et al (1991).…”

“…The lymphatic spread of infection detected by the enlarged, infected lymph-nodes in seven of our eight patients, either regional or some distance from primary lesions, appears to be an important aspect that is peculiar to BDCL, and we have not observed this in over 60 cases of LCL due to L. (L.) amazonensis (Silveira et al 1991, Moraes & Silveira 1994, or in all of twelve cases of frank ADCL (Silveira, unpublished observations). In the same way, no evidence of lymphatic dissemination was found in six cases of ADCL in the state of Maranhão, Brazil and patients with ADCL due to parasites of the mexicana complex in Venezuela (Convit et al 1972), Mexico (Velasco et al 1989) and Peru (Franke et al 1990).…”

American tegumentary leishmaniasis: an uncommon clinical and histopathological presentation

“…While the case under study was apparently an infection by L. amazonensis , a molecular biology investigation for confirmation of the species was not however possible. 9 …”