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More than 120 years ago, Jonathan Hutchinson recorded the first case of sarcoidosis,l which he called "a case of livid papillary psoriasis." Hutchinson's patient presented with purplish skin lesions and "gout" and later died of renal failure. The renal failure was attributed to gout, but could have been caused by persistent hypercalemia, hypercalcuria, or multiple kidney stones due to sarcoidosis. Despite advances in diagnostic techniques made since Hutchinson's time, the problem of distinguishing organ dysfunction due to sarcoidosis from other causes remains.
The diagnostic criteria for sarcoidosis, initially proposed in the 1950s by the International Sarcoidosis Association (now known as the World Association of Sarcoidosis and Other Granulomatous Diseases [WASOG]), included that granulomas be present in two or more organs with no agent known to cause a granulomatous response identified.2 This group also pointed out that a positive Kveim-Stilzbach test could also be used to support the diagnosis, and that false-positive Kveim-Stilzbach tests were infrequent. The histologic hallmark of sarcoidosis remains the finding of noncaseating granuloma, but unfortunately this is neither sensitive nor specific.3 Environmental and infectious causes of noncaseating granulomatous inflammation exist. In addition, some patients with sarcoidosis will have necrotizing areas within their granulomas, likely due to a more intense vascular inflammation.4,5 Furthermore, clinicians rarely go to the trouble of trying to demonstrate granulomas in more than one organ.
The most frequent biopsy sites are lung, lymph node, skin, and liver, but finding granulomas in any of these organs is never specific for sarcoidosis. In the liver, a necrotic granulomatous response to infection, even with Mycobacterium tuberculosis, is usually not seen. Also, granulomas isolated to the liver occur both from a variety of causes and of unknown significance.7Thus, the finding of noncaseating granuloma in the liver is less specific than that in the lung.
How specific to...