Actinomycosis as a neglected diagnosis of mediastinal mass.

Thoracic actinomycosis is a rare disease in children. Diagnosis is typically delayed, since the presentation can be very similar to that of malignant tumors, tuberculosis, and fungal infections. We here present the case of a 9-year-old girl who was treated for tuberculosis at the first presentation, for non-Hodgkin's lymphoma at the second presentation, and for chronic granulomatous disease at the third presentation before actinomycosis was finally diagnosed by culture.