Researchers herein report a case of concurrent cardiac sarcoidosis and large-vessel aortitis detected by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and followed up during immunosuppressive therapy

Positron emission tomography (PET) is an operator-independent, noninvasive metabolic imaging modality based on the regional distribution of the glucose analog 18Ffluorodeoxyglucose (FDG). FDG-PET is a sensitive and specific imaging tool for large-vessel vasculitis and increases the overall diagnostic accuracy in cardiac sarcoidosis.

Sarcoidosis is a multisystem granulomatous disease of undetermined etiology, involving the lung, heart, liver, spleen, eye, parotid gland, or other organs and tissues. To our knowledge, this is the first report of concurrent cardiac sarcoidosis and large-vessel aortitis detected by FDG-PET. The initial high-dose prednisolone treatment markedly diminished the abnormal FDG uptake in both the heart and extracardiac lesions, including the large vessels.

Results

FDG-PET may have potential application for imaging inflammatory cardiovascular diseases, including cardiac sarcoidosis, large-vessel arteritis, and atherosclerosis. Granulomatous aortitis in sarcoid patients, also known as “sarcoid aortitis” (9), is a rare manifestation of sarcoidosis. Several previous reports have presented cases of large-vessel vasculitis in sarcoidosis patients (9-11); however, no cases have been documented by FDG-PET.

When large vessels are involved in sarcoidosis, sarcoid vasculitis may mimic other types of vasculitis, including Takayasu arteritis, which preferentially affects young women with an average age of fewer than 40 years old. The patient’s age of 62 years at the time of diagnosis was atypical for Takayasu arteritis. Although histology of a biopsy specimen was not available in the present case, we may reasonably assume that this large-vessel vasculitis was not Takayasu arteritis, but rather “sarcoid aortitis”.

Weiler et al. (10) reported that sarcoidosis generally precedes aortitis syndrome, and the time lag between the diagnosis of sarcoidosis and that of aortitis syndrome is several years in most patients in concurrent cases of sarcoidosis and aortitis syndrome.

The five-year time lag in our case is comparable to their findings. IgG4-related disease (IgG4- RD) is a systemic inflammatory and sclerosing disease characterized by the elevation of the serum IgG4 levels and IgG 4-positive plasmacyte infiltration in tissues, including the cardiovascular system and especially the abdominal aorta.

We believe that IgG4-RD was not involved in the present case, as the laboratory examinations showed that the serum IgG4 level was not elevated (at 26.9 mg/dL) at baseline, and serial FDG-PET/CT did not reveal any extravascular involvement typical of IgG4-RD, such as the pancreas, lacrimal and/or salivary glands, retroperitoneum, or bile duct.

Physicians should, therefore, be aware that cardiac sarcoidosis and asymptomatic large-vessel aortitis can coexist. High-dose prednisolone was initially effective in treating both lesions but additive MTX was needed to treat the recurrence of cardiac sarcoidosis during the tapering of prednisolone. FDG-PET is a useful tool for detecting cardiac sarcoidosis concomitant with large-vessel aortitis and can also be used to monitor the effectiveness of such treatment.