In most patients, however, there is a rapidly progressive cellulitis as the ulceration, which begins in the gum, now enlarges to involve the mucosa of the adjacent cheek. There are numerous bacteria in the necrotic tissue, predominantly Vincent's organisms, but many secondary bacterial invaders as well; the margins of the advancing lesion are purulent. Blood vessels, which were initially spared, suddenly undergo thrombosis, and the gangrenous process becomes deeper and more extensive as part of the cheek sloughs. Later in the process, the edges of the sloughed area are usually well defined. The maxilla and mandible are often exposed and extensive necrosis and erosion of bone may be present.

Histologically, the most striking late feature is necrosis with a ghost outline of previously vital tissue (Fig. 39.3). There is often a fine filamentous chain of bacteria attached to the surface of exposed bone (Figs. 39.4 and 39.5); these bacterial colonies may invade and erode the underlying bone. Organisms are also present at the advancing edge of the soft tissue lesion but there is little inflammatory cell response. As the lesions heal with proper therapy (usually penicillin and a good diet), granulation tissue and extensive fibrosis are noted. If the child is relatively well nourished, there may be a satisfactory end result, but usually the resulting deformity is quite disfiguring with a large, gaping hole marring the cheek and face.

Fig. 39.3 Noma. This specimen from the margin of a lesion shows extensive coagulation necrosis of epithelium, fatty tissue and muscle with masses of bacteria on the deep surface. X6.5. AFIP 75-2643. (From C.H. Binford and D.H. Connor, (eds):Pathology of Tropical and Extraordinary Diseases. Armed Forces Institute of Pathology, Washington DC, 1976).

Fig. 39.4 Noma. Facial bone with a layer of filamentous bacteria adherent to its surface. X675. AFIP 75-2639. From C.H. Binford and D.H. Connor, (eds):Pathology of Tropical and Extraordinary Diseases. Armed Forces Institute of Pathology, Washington DC, 1976).

Fig. 39.5 Noma. Biopsy specimen of a facial bone with masses of bacteria in the eroded bone. X970. AFIP 75-2641. (From D.H. Connor and F.W. Chandler (eds): Pathology of Infectious Diseases. Appleton & Lange, Stanford, Conn,1997).