**Abstract**

Sarcoidosis is a rare unknown etiology multisystem inflammatory disease in which noncaseating granulomas (a collection of inflammatory cells) forms and growth in various organs, involving predominantly lungs, intrathoracic lymph node, skin, and eyes. Most commonly, affecting patients between 20 and 40 years old of age, although could be observed at any age (female predominance; rare in Asians). The areas of the body usually affected by sarcoidosis are lungs, skin, or lymph nodes; pulmonary and mediastinal involvement is seen in over 90% of patients. Less commonly eyes, liver, heart, and brain are involved. Any organ, however, can be affected. Early diagnosis of sarcoidosis can be difficult due to few signs and symptoms in its early stages, and when disease does occur, it may mimic other pathologies, and it is achieved through chest X-ray, computed tomography (CT)-high resolution CT (HRCT), gallium scans. Fluoro-deoxy glucose-positron emission tomography (FDG-PET) is another useful tool to assess the extent of disease and has a potential to evaluate the clinical management of patients responding or not to the treatment. Imaging gives, moreover, an important contribution to the evaluation of prognosis and follow-up.

**Keywords:** sarcoidosis, diagnosis, early diagnosis, chest X-ray, computed tomography (CT)-high resolution CT (HRCT), gallium scans, fluoro-deoxy glucosepositron emission tomography (FDG-PET)
