Clinics in diagnostic imaging (108). Tuberculous dactylitis of the thumb, mediastinal and left hilar lymphadenopathy, and probable left cervical lymphadenopathy.

A five-year-old girl presented with a history of left neck swelling for one week and right thumb swelling for three weeks. Imaging studies revealed a "collar-stud" abscess in the left side of the neck, massive mediastinal lymphadenopathy with a left anterior chest wall abscess, and right thumb dactylitis that was typical of tuberculosis (TB). Surgical drainage of the left neck swelling revealed acid-fast bacilli. Young children are more susceptible to tuberculous infection, and at greater risk of extrapulmonary spread. A child infected with TB indicates recent transmission, usually from an adult. Good contact tracing is essential. Individuals with HIV infection are also at greater risk of TB and atypical mycobacterial infection as well extrapulmonary TB. The clinical and radiological features of both pulmonary and extrapulmonary TB are discussed, with additional illustrative cases.