Cutaneous amebiasis: 50 years of experience.

Although cutaneous amebiasis (CA) is a rare disease, it is a public health concern worldwide, particularly in developing nations. It gains importance because of its severe clinical course, which can be confused with other disorders. Therefore, knowledge of its clinical features, histopathology, and pathogenesis is essential. We present a retrospective analysis over 50 years of 26 patients with CA who were diagnosed and treated at 2 Mexican institutions. Our main focus was to draw clinical information to identify mechanisms by which amebae reach the skin, occurring in a relatively small percentage of infected individuals. The recorded data included age and sex of the patients, form of presentation, any associated illnesses and/or factors, and methods for diagnosis. Histologic slides were reviewed in all cases; cytologic preparations also were available for 6 cases. Most patients were male (overall male to female ratio, 1.9 to 1). The disease always presented as painful ulcers containing varying amounts of amebae microscopically; the amebae were fairly easy to identify with routine stains, particularly when examination of tissue or smears was prepared from the edges of the ulcer instead of the necrotic centers. Erythrophagocytosis by the trophozoites was found and represented an unequivocal sign of its pathogenicity. We review the 2 mechanisms by which the organisms reach the skin. Most cases resolve with the use of specific antiamebic drugs; however, if left untreated, progression is rapid and unrelenting, sometimes with massive destruction of skin and subcutaneous tissues. Therefore, CA is a particularly virulent form of amebiasis.

Lucio's phenomenon is a necrotizing panvasculitis: mostly a medium-sized granulomatous arteritis.

Lucio's phenomenon (LPh) is a vasculitis clinically described in 1852 and microscopically documented in 1948 in patients with diffuse lepromatous leprosy; however, at present, there is no a clear concept about the pathogenesis of the necrosis, or about the type, size, and site of the damaged vessel. The objective of this study was to elucidate the type, size, site, and form of vessel damage in LPh in a retrospective, clinical, and histopathological study. Clinical information was obtained from the charts and records and/or from the histopathology request. Slides stained with hematoxylin and eosin, Ziehl-Neelsen, and Fite-Faraco were retrieved from our files. Direct immunofluorescence had been performed in 6 cases. Twelve cases fulfilled clinical evidence to make unequivocal diagnosis of diffuse lepromatous leprosy with LPh. All of them had necrotic, irregular, purpuric, and/or ulcerative lesions, which under the microscope showed medium-sized arteries, with their walls involved by clusters of macrophages containing large amounts of bacilli, distortion of the structure of the vessel wall, narrowing, and obliteration of their lumen. Smaller vessels showed changes of the leukocytoclastic type. LPh is a distinctive type of granulomatous and necrotizing panvasculitis; the involved vessels are mostly medium-sized arteries, located deeply in the skin, at the base, and within the hypodermis, but any other vessel is likewise involved, their occlusion leads to ischemic necrosis of the whole skin, frequently with detachment of the epidermis. These changes explain clearly and logically the clinical features observed more than 150 years ago.

Cutaneous amebiasis in pediatrics.

BACKGROUND: Cutaneous amebiasis (CA), which is still a health problem in developing countries, is important to diagnose based on its clinical and histopathologic features. OBSERVATIONS: Retrospective medical record review of 26 patients with CA (22 adults and 4 children) treated from 1955 to 2005 was performed. In addition to the age and sex of the patients, the case presentation, associated illness or factors, and method of establishing the diagnosis, clinical pictures and microscopic slides were also analyzed. CONCLUSIONS: Cutaneous amebiasis always presents with painful ulcers. The ulcers are laden with amebae, which are relatively easy to see microscopically with routine stains. Erythrophagocytosis is an unequivocal sign of CA. Amebae reach the skin via 2 mechanisms: direct and indirect. Amebae are able to reach the skin if there is a laceration (port of entry) and if conditions in the patient are favorable. Amebae are able to destroy tissues by means of their physical activity, phagocytosis, enzymes, secretagogues, and other molecules.

Histopathology of cutaneous amebiasis.

Cutaneous amebiasis (CA) is the manifestation in the skin and underlying soft tissues of the pathogenic properties of Entamoeba histolytica, which may be the only expression of the infection or may be associated with disease in other organs. So far, there have been only isolated case reports on this disease. We herein report the histopathologic findings on a series of seven cases, six adults and one child, of CA. The most common findings include ulcers, areas of necrosis, mixed inflammatory infiltrates, and the presence of trophozoites, the invasive form of the parasite. CA is a very rare and severe disease, it is progressive and destructive; erythrophagocytosis, a microscopic sign of pathogenicity, is always seen in CA.