Asymptomatic gastrocnemius muscle biopsy: an extremely sensitive and specific test in the pathologic confirmation of sarcoidosis presenting with hilar adenopathy.

OBJECTIVE To evaluate asymptomatic gastrocnemius muscle biopsy as a tool in the histologic confirmation of the diagnosis of sarcoidosis. METHODS Twenty-two patients admitted over a 2-year period to our department with bilateral hilar adenopathy and a variety of symptoms compatible with sarcoidosis were studied prospectively. Besides a complete history and physical, serum angiotensin converting enzyme (SACE) determination, pulmonary function, slit lamp eye examination, PPD skin test, gallium 67 scan and gastrocnemius muscle biopsy were performed. RESULTS The biopsy revealed non-caseating granuloma in all patients, confirming the diagnosis of sarcoidosis. No other patient in our department received this diagnosis over the 2-year period of the study. The procedure was well tolerated by all patients and almost zero morbidity was noted. Erythema nodosum was present in 68.2% of the patients, PPD was negative in all of them, SACE was elevated in 59.1% and pulmonary function was normal in the majority. CONCLUSION The impressive sensitivity of asymptomatic gastrocnemius muscle biopsy, its safety and ease of performance, along with the extreme rarity of muscle involvement by other granulomatous diseases included in the differential diagnosis, may render it the procedure of choice for the histologic confirmation of sarcoidosis presenting with hilar adenopathy.