The upper half of the neck is the most frequent site of actinomycosis, except the face. Often the two regions are attacked simultaneously. Writers who have studied the question point out the tendency of the mycelian infection to progress toward the surface. Bollinger,1 in particular, says that the condition resembles tuberculosis so closely that one may mistake it for that disease, but that soon the lesion becomes red and slightly edematous, and finally an abscess collects and a fistula is produced. When the disease is active deep in the neck, the primary lesion is often cicatrized, and only scar tissue remains as evidence of the original infection.
Actinomycosis of the mediastinum is always secondary. The route of penetration of the fungus, according to Bollinger, who first described it in 1877, is either through a tooth or the tonsils or else through the air or food
VAN DEN WILDENBERG L. DEEP ACTINOMYCOSIS OF THE NECK AND MEDIASTINUM. Arch Otolaryngol. 1928;7(1):50–56. doi:10.1001/archotol.1928.00620010058006