Tuberculosis, head and neck

The most common location of head and neck tuberculosis is in the neck lymph nodes; this form represents about 15% of cases of extrapulmonary tuberculosis, and about 1.5% of all new cases of tuberculosis present in this way. Neck tuberculosis outside the lymph nodes is rarely seen nowadays. The most common extranodal localization is the larynx, followed by the temporal bone and pharynx; other sites such as the sinonasal cavity, thyroid gland and skull base may be affected, but such involvement is very rare. The diagnosis of head and neck tuberculosis may be difficult, as the disease is not very well known.

Cervical tuberculous lymphadenitis is also known as scrofula. It is often bilateral and presents as painless masses. The adenopathies are initially homogeneous, but show later central necrosis, corresponding on CT to central areas of low density surrounding by an enhancing rim (Fig.1). Such nodes may closely resemble adenopathies as seen in metastatic squamous cell carcinoma head and neck. In a later stage, nodal calcifications may be seen, which helps to differentiate the tuberculous nodes from cancer; however, nodal calcification may also be seen in other diseases, such as metastatic thyroid cancer.

The imaging findings in laryngeal tuberculosis are bilateral soft tissue thickening and infiltration of the pre-epiglottic and paraglottic spaces, without the presence of a focal mass (Fig.2). The laryngeal framework usually remains intact. The differential diagnosis mainly includes other inflammatory laryngeal conditions.

The imaging findings of tuberculosis at other head and neck sites are also rather nonspecific; usually inflammatory soft tissue thickening is seen, but in advanced cases bony erosions and neoplastic-like soft tissue masses may be encountered (petrous apex (VI:2), Fig. 2).

RH