Endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of extra-pulmonary tuberculosis

The incidence of extra-pulmonary tuberculosis (EPTB) is surprisingly high among certain subgroups of patients in industrialized countries. Diagnosis is often difficult and can require costly invasive workup. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a safe, minimally invasive, accurate, out-patient diagnostic modality for assessing mediastinal and abdominal lymphadenopathy and masses.

To evaluate the usefulness of EUS-FNA for diagnosing EPTB.

Retrospective 6-year review, including all patients who had evidence of lymphadenopathy or mass on computed tomography scan accessible by EUS and consideration of tuberculosis (TB) in the differential diagnosis.

Of 81 potential patients, a total of 20 cases with EPTB diagnosed by EUS-FNA were identified. Necrotizing granulomas had a 58% likelihood of TB vs. 14% for other cytologic findings (P < 0.0001); necrosis was also predictive, with a 44% likelihood of TB vs. 19% (P < 0.0225). EUS-FNA cytology was diagnostic for TB when an African-born patient had necrotizing granulomas (P < 0.0001), and was highly suggestive with necrosis alone (P < 0.0514). Non-necrotizing granulomas were not predictive of TB and an alternative diagnosis was more likely, including sarcoidosis and cancer.

EUS-FNA is a useful diagnostic modality that should be used early in the diagnostic workup of suspected EPTB.