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Spread of amebic infection to other parts of the body occurs by embolization or direct invasion. The colon and liver (Figs. 1.8 and 1.9) are most frequently infected, but lung (Fig. 1.9), pleura, pericardium, brain (Fig. 1.10), genitalia, stomach, small bowel, spleen, and skin are other sites of infection; rare involvement of bone and aorta has been reported. Thoracic amebiasis is usually caused by direct spread from hepatic infection: over 75% of amebic infections in the chest develop from contiguous erosion of a liver abscess through the diaphragm (Fig. 1.9). Spread of amebae may take place by migration through the vertebral venous system to the brain and lungs without liver involvement, and direct spread from the gut to adjacent organs and tissues is common.

Fig. 1.8 Amebic abscesses of the liver. (A) Diffuse, well-defined amebic ulcers of the colon in a patient with fatal amebiasis. The cut surface of the liver contains multiple large amebic abscesses (Courtesy of A. M. Fallis). (B) Huge abscess perforating through the surface of the right lobe of the liver. AFIP 1099409-1. (C) Large central hepatic abscess on cross-section. AFIP 53-4923. (D) Histological section of a hepatic amebic abscess with extensive inflammatory cell infiltrate, predominantly neutrophils. X112. AFIP 52-1160.

Fig. 1.9 Right lung and liver. Large hepatic amebic abscess in the dome of the right lobe of the liver, extending through the diaphragm and right pleura and causing an abscess in the right lower lobe. Thoracic amebiasis is almost always an extension of a hepatic abscess. The right hemithorax is involved by direct extension from an abscess in the right lobe of the liver, whereas a left lobe abscess may lead to empyema and lung abscess in the left hemithorax.

Fig. 1.10 Amebic abscesses of the brain in two patients (A) and (B) AFIP 203398-1.

	Extraintestinal Amebiasis Spread of amebic infection to other parts of the body occurs by embolization or direct invasion. The colon and liver (Figs. 1.8 and 1.9) are most frequently infected, but lung (Fig. 1.9), pleura, pericardium, brain (Fig. 1.10), genitalia, stomach, small bowel, spleen, and skin are other sites of infection; rare involvement of bone and aorta has been reported. Thoracic amebiasis is usually caused by direct spread from hepatic infection: over 75% of amebic infections in the chest develop from contiguous erosion of a liver abscess through the diaphragm (Fig. 1.9). Spread of amebae may take place by migration through the vertebral venous system to the brain and lungs without liver involvement, and direct spread from the gut to adjacent organs and tissues is common. .. .. Fig. 1.8 Amebic abscesses of the liver. (A) Diffuse, well-defined amebic ulcers of the colon in a patient with fatal amebiasis. The cut surface of the liver contains multiple large amebic abscesses (Courtesy of A. M. Fallis). (B) Huge abscess perforating through the surface of the right lobe of the liver. AFIP 1099409-1. (C) Large central hepatic abscess on cross-section. AFIP 53-4923. (D) Histological section of a hepatic amebic abscess with extensive inflammatory cell infiltrate, predominantly neutrophils. X112. AFIP 52-1160. Fig. 1.9 Right lung and liver. Large hepatic amebic abscess in the dome of the right lobe of the liver, extending through the diaphragm and right pleura and causing an abscess in the right lower lobe. Thoracic amebiasis is almost always an extension of a hepatic abscess. The right hemithorax is involved by direct extension from an abscess in the right lobe of the liver, whereas a left lobe abscess may lead to empyema and lung abscess in the left hemithorax. .. Fig. 1.10 Amebic abscesses of the brain in two patients (A) and (B) AFIP 203398-1. Next Page Previous Page