Sarcoid is a chronic inflammatory granulomatous response that can occur in almost any site in the body. Uptake can vary and may be related to the degree of activity leading to heterogenous distribution. Uptake tends to be decreased in the setting of steroid therapy. The typical pattern involves an 'inverted lambda sign' with relatively symmetric bilateral mediastinal and bihilar uptake. When the salivary glands are involved, the prominent pattern of uptake in the face is often referred to as the 'panda' sign. The initial inflammatory infiltrate consisting of mononuclear cells, subsequently form granulomas, where FDG may be accumulated. The degree of metabolic uptake may reflect the degree of disease activity and may actually decrease following steroid therapy.

Possible limitations:
Possible false positive interpretation for metastases in patients with coexisting malignancy can occur.