A Study On Histopathology Of Dark Pigmented Fungal Infections

ObjectiveThe study aimed to analyze the pattern of the relationship between the pathogens and the inflammatory cells in the tissues infected by dark pigmented fungi and in the other hand to explore the mechanism of host immune defense against this infection too.MethodsThirty-three Formalin fixed paraffin-embedded tissues of skin lesion samples from patients with dark pigmented fungal infection were collected.The expression of CD86 in macrophages of infected tissues was detected by immunohistochemistry.The clinical data of 33 patients with dark pigmented fungal infection were retrospectively analyzed,and the relationship between inflammatory pattern and clinical manifestations was assessed.The pathogenic agent of a cattle injured lower extremity patient with dark pigmented fungal infection was identified by gene sequencing and followed up clinically.Results1.Thirty-three patients with dark pigmented fungal infection had skin lesions confined to the upper and lower limbs(90.9%),2 cases have got lesions on the face(6.7%)and disseminated lesions in 1 case(limbs,bilateral axilla,trunk)(3.3%).2.Thirty-one cases(93.9%)showed epidermal pseudo-epithelioma like hyperplasia,2 cases showed the signs of epidermal hyperplasia(6 %),whereas 19 cases(57.6%)showed typical features of granulomatous inflammation which composed of micro-abscess that formed by aggregation of neutrophils and surrounded by epithelioid cells or polynuclear macrophages.High cellular component infiltration is also seen in the tissue samples,the essential components consist of neutrophils,eosinophils,plasma cells,lymphocytes,histiocytes and multinucleated macrophages(Giant cells).3.The expression of CD86 on macrophages was detected in the tissue of the lesion samples which was taken from the patients infected by dark pigmented fungus.4.Fonsecaea Monophora was identified as the causative pathogenic organism of the dark pigmented fungus infection patient who had injury caused by cattle attack during the farm work.The patient totally cured after orally administered Itraconazole and no recurrence occurred during the follow-up period of 1 year.ConclusionThe main manifestation of dark pigmented fungal infection is the localized skin lesions.The expression of CD86 in macrophages can stimulate the formation of the inflammatory granuloma and limit the spread of the infection.