The cases of actinomycosis of the thorax have been divided into two groups: primary and secondary. Actinomycosis of the thorax is considered primary when the infection involves some organ or tissue within the thorax, primarily. Secondary actinomycosis of the thorax is a condition in which the organs or tissues of the thoracic cavity become involved secondarily to an actinomycotic lesion elsewhere in the body.
Clinically, Naussac1 classified actinomycosis of the lung as: (1) broncho-actinomycosis, (2) pneumo-actinomycosis and (3) pleuropneumo-actinomycosis. Choux2 added a fourth group, thoracopulmonary actinomycosis, to designate the involvement of the thoracic wall.
In primary actinomycosis of the thorax, infection may take place by inhalation of the organism or by infection of the esophagus, from which the mediastinum, pleura and lung become involved. The lungs may be involved secondarily, by direct extension, by embolic or metastatic means, or in the manner in which primary actinomycosis is acquired,