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

SETTING: 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.

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

DESIGN: 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.

RESULTS: 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.

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