Sarcoidosis or sarcoid-like reaction?

Sarcoidosis is considered as a systemic inflammatory disease of unknown etiology with the formation of non-caseous granulomas in tissues. Skin lesion in sarcoidosis can proceed isolatedly (from 10 to 30% of cases) or be a manifestation of systemic sarcoidosis. The histological picture of sarcoidosis is not pathognomonic, and laboratory diagnostics is non-specific as the diagnosis of sarcoidosis does not have precisely established criteria. Etiological therapy does not exist. In addition to the disease’s typical manifestations, a sarcoid-like reaction has been identified. This disorder is represented by the formation of sarcoid-like granulomas in various organs and tissues, which are histologically indistinguishable from sarcoidosis. It occurs as a response to exogenous factors (implants, tattoos), when using pharmaceutical products (interferons, antiviral drugs), in malignant neoplasms and infections. Sarcoid-like skin reactions may be limited or widespread, involving the intrathoracic lymph nodes and lung interstitium. We present an observation of a patient with generalized sarcoidosis with lesions of the skin (scarring sarcoidosis), lungs, intrathoracic and peripheral lymph nodes, the clinical picture of which, due to the features of manifestations, is indistinguishable from a sarcoid-like reaction.