Extrapulmonary tuberculosis (TB) refers to the hematogenous spread of Mycobacterium tuberculosis.
Pathology
Extrapulmonary tuberculosis can occur as a primary form of the disease, i.e. direct infection of an extrapulmonary organ without the presence of primary pulmonary tuberculosis or it can occur as a result of the spread of primary pulmonary tuberculosis.
It appears classically as tuberculous granulomata (tuberculomas) within the affected organs. However, certain forms of the disease exist manifesting with specific findings:
-
CNS
-
head and neck
-
musculoskeletal
-
-
visceral tuberculosis
-
scrotal tuberculosis (testes, epididymis, seminal vesicles, ductus (vas) deferens)
Radiographic features
Widely variable dependent on the site of involvement. It is best to refer to site-specific articles.
As tuberculous organ infection can mimic malignant disease, studies have reported the usefulness of 18 FDG PET-CT in evaluating and following up patients in whom the diagnosis is in doubt 4.