PURPOSE: The diagnosis of sarcoidosis requires compatible clinicoradiologic features and pathologic findings. Multiple techniques are available to achieve a pathologic diagnosis of sarcoidosis. The sensitivity for diagnosing characteristic non-caseating granulomas with endobronchial ultrasound (EBUS) is high. We evaluated the yield of CD68 staining in inconclusive bronchoscopic specimens.
METHODS: We retrospectively reviewed 279 consecutive patients with hilar or mediastinal adenopathy who underwent EBUS with transbronchial needle aspiration (TBNA) at Yale-New Haven Hospital between March 2009 and April 2011. Patients were considered to meet criteria for a diagnosis of sarcoidosis if tissue demonstrated noncaseating granulomas with negative cultures. We compared the relative yield of transbronchial biopsies (TBBX) and EBUS-TBNA and evaluated the number of patients requiring mediastinoscopy for a diagnosis. In those patients requiring mediastinoscopy, CD68 stains were performed on the EBUS specimens. CD68 is a well-accepted stain to highlight histiocytes, including epithelioid histiocytes seen in granulomas. In this analysis, the stain differentiated nonspecific fibrous tissue from hyalinized granulomas.
RESULTS: Pathologic findings compatible with sarcoidosis were identified in 34 patients (13 males, mean age 50 years). Of these, 9 underwent EBUS-TBNA alone; 25 underwent both EBUS-TBNA and TBBX; and 2 underwent EBUS-TBNA, TBBX, and mediastinoscopy. EBUS-TBNA demonstrated noncaseating granulomas in 30 of 34 patients (88%). Of those patients with nondiagnostic EBUS-TBNA, 2 had evidence of sarcoidosis on TBBX, constituting an additional yield of 6%. Of those patients with no diagnosis following both EBUS-TBNA and TBBX, 2 were diagnosed with sarcoidosis on the basis of mediastinoscopy, for an additional yield of 6%; CD68 immunostains were positive in both of these patients.
CONCLUSIONS: EBUS-TBNA has the highest diagnostic yield for sarcoidosis of all bronchoscopic techniques. TBBX provides a small additive increase. When combined with CD68 staining, bronchoscopic techniques diagnosed all known cases of sarcoidosis in our population.
CLINICAL IMPLICATIONS: Patients with suspected sarcoidosis should undergo EBUS-TBNA as the first diagnostic test. In regions where it is not available, referral to a center with EBUS is recommended. CD68 staining should accompany specimens in which classic granulomas are not identified.
DISCLOSURE: The following authors have nothing to disclose: Lauren Tobias, Guoping Cai, Jonathan Puchalski
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