This is a slice of lung showing collapse, with an abscess cavity of 2 cm. across associated with
pleural and lung scarring in the basal part of the specimen, with collapse and multiple small
abscesses in the mid-area, again, associated with extensive pleural scarring. Pulmonary
actinomycosis may be primary or secondary, the latter resulting from spread of the disease from
below the diaphragm, particularly the liver, but occasionaly from a cervico-facial infection.
Primary pulmonary actinomycosis is mainly a peripheral lung lesion, and usually involves the
pleura early in its development. Pleural involvement results in either empyema, or dense pleural
adhesions, to which the infection may spread directly to involve the chest wall.