Actinomycosis is a rare infection caused by a group of bacteria called Actinomyces. It typically appears as a slow-growing lump or mass on the face, neck, chest, or abdomen. The most common symptom is a painless lump or mass that may look like a tumor. It may also be accompanied by fever, night sweats, weight loss, and fatigue.
The appearance of actinomycosis can vary depending on where the infection is located. In the lungs, the infection typically presents as a chest wall mass with air-fluid levels and thick pus-filled abscesses. In the abdomen, it may appear as an inflamed appendix, an abscess, or a mass in the liver or spleen. In the head and neck, the infection may present as a tumor-like mass with thick pus-filled abscesses.
The lump or mass associated with actinomycosis can vary in size, ranging from small pea-sized lumps to large, grapefruit-sized masses. The mass may have a yellow, cheesy appearance due to the presence of sulfur granules. The mass may also be firm or soft, depending on the amount of inflammation and pus present.
Actinomycosis can also be associated with other signs and symptoms, such as a fever, night sweats, weight loss, and fatigue. A doctor may order tests, such as a CT scan or MRI, to get a better look at the infection and determine the best course of treatment.