Study objectives: The ability to diagnose sarcoidosis cytologically has been reported previously, but the method is rarely used. Endoscopic ultrasonography (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 diagnosis of sarcoidosis.
Patients and methods: Nineteen patients with suspected sarcoidosis were investigated using EUS-FNA with a linear echoendoscope and a 22-gauge Hancke-Vilman needle.
Measurements and results: In all 19 patients, EUS revealed enlarged mediastinal 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 vessels in five cases. The amount of aspirate obtained using EUS-FNA was adequate in all patients, and contained blood in excess of normal in some, indicating a high degree of vascularity. Cytology demonstrated epithelioid cell granuloma formation, suggesting sarcoidosis. Mycobacterial cultures were negative in all of the patients except one, in whom the final diagnosis was tuberculosis. 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 method of aspirating material for cytology and mycobacterial cultures. We believe it will provide a useful alternative in the diagnosis of sarcoidosis.