Snapshot A 52-year-old African American woman presents to her primary care physician for worsening cough accompanied by fatigue, fever, and malaise. Physical exam is remarkable for an erythematous, nonulcerated, and tender nodule over the bilateral shins. A chest radiograph is obtained, which demonstrate bilateral hilar adenopathy without any appreciable pulmonary parenchymal infiltrates. Introduction Definition a systemic inflammatory disease that is characterized by the presence of non-caseating granulomas Sarcoidosis staging stage 1 bilateral hilar adenopathy stage 2 bilateral hilar adenopathy with parenchymal infiltrates stage 3 diffuse parenchymal infiltrates in the absence of hilar adenopathy stage 4 pulmonary fibrosis demonstrating honeycombing Epidemiology Incidence the lung is most commonly involved most common in African Americans Etiology Unknown Pathogenesis macrophages present antigens to T-cells Th1 cells are recruited and produce IFN-y, TNF, and IL-2 results in granulation formation Associated conditions neurosarcoidosis dilated and restrictive/infiltrative cardiomyopathy myocarditis hypercalcemia erythema nodosum uveitis acute interstitial nephritis lupus pernio restrictive lung disease rheumatoid-lie arthropathy Presentation Symptoms constitutional symptoms (e.g., fever, malaise, and anorexia) dyspnea arthralgias Physical exam erythema nodosum anterior uveitis cranial nerve VII involvement (worrisome for neurosarcoidosis) Imaging Chest radiograph indication initial imaging study in the evaluation of sarcoidosis findings hilar adenopathy (hallmark) reticular opacities parenchymal nodules High-resolution CT indication to further evaluate abnormalities demonstrated on chest radiography Studies Laboratory abnormalities hypercalcemia and hypercalciuria elevated angiotensin-converting enzyme (ACE) levels (~60% of cases) Biopsy of the affected organ preferred site of biopsy is the lesion that is most superficial non-caseating granuloma Differential Lymphoma differentiating factor a biopsy would not demonstrate noncaseating granuloma Treatment Medical oral corticosteroids indication considered first-line treatment Complications Pulmonary fibrosis Pulmonary hypertension Heart failure Prognosis Generally good in most patients