Diagnosing sarcoidosis using endosonography-guided fine-needle aspiration

Study objectives: The ability to diagnose sarcoidosis cytologically has bee n reported previously, but the method is rarely used. Endoscopic ultrasonog raphy (EUS) is a sensitive technique for detecting mediastinal lymph nodes, which in addition provides an opportunity to carry out guided fine-needle aspiration (FNA) cytology. We report herein on the use of EUS-FNA in the di agnosis of sarcoidosis. Patients and methods: Nineteen patients with suspected sarcoidosis were inv estigated using EUS-FNA with a linear echoendoscope and a 22-gauge Hancke-V ilman needle. Measurements and results: In all 19 patients, EUS revealed enlarged mediast inal lymph nodes (mean size, 2.4 cm), located subcarinally (n = 15), in the aortopulmonary window (n = 12), or in the lower posterior mediastinum (n = 5). The nodes had an isoechoic or hypoechoic appearance, with atypical ves sels in five cases. The amount of aspirate obtained using EUS-FNA was adequ ate in all patients, and contained blood in excess of normal in some, indic ating a high degree of vascularity. Cytology demonstrated epithelioid cell granuloma formation, suggesting sarcoidosis. Mycobacterial cultures were ne gative in all of the patients except one, in whom the final diagnosis was t uberculosis. The specificity and sensitivity of EUS-FNA in the diagnosis of sarcoidosis were 94% and 100%, respectively. Conclusions: EUS of mediastinal lymph nodes in sarcoidosis reveals certain characteristic features, However, it is not capable of differentiating the lesions from tuberculosis or malignancy. EUS-FNA is a safe and sensitive me thod of aspirating material for cytology and mycobacterial cultures. We bel ieve it will provide a useful alternative in the diagnosis of sarcoidosis.