Esma A. Akin

This article does not include an Please see the accompanying Point by Colm B. Kelleher and Terence Z. Wong.

The use of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography combined with computed tomography (PET/CT) is well established in the evaluation of alimentary tract malignancies. This review of the literature and demonstration of correlative images focuses on the current role of PET/CT in the diagnosis (including pathologic/clinical staging) and post-therapy follow-up of esophageal, gastric, and colorectal cancers. PET/CT provides utility in the management of esophageal cancer, including detection of distant disease prior to resection. In gastric cancer, PET/CT is useful in detecting solid organ metastases and in characterizing responders vs. non-responders after neoadjuvant chemotherapy, the latter of which have poorer overall survival. In patients with GIST tumors, PET/CT also determines response to imatinib therapy with greater expedience as compared to CECT. For colorectal cancer, PET/CT has proven helpful in detecting hepatic and other distant metastases, treatment response, and differentiating post-radiation changes from tumor recurrence. Our review also highlights several pitfalls in PET/CT interpretation of alimentary tract lesions.

Concurrent presentation of retinal vasculitis with mixed sclerotic and lytic bone lesions is rare. We present the case of a 37-year old woman with a several year history of episodic sternoclavicular pain who presented for rheumatologic evaluation due to a recent diagnosis of retinal vasculitis. We review the differential diagnosis of retinal vasculitis, along with the differential diagnosis of mixed sclerotic and lytic bone lesions. Ultimately, bone marrow biopsy confirmed diagnosis of chronic recurrent multifocal osteomyelitis (CRMO). Concurrent presentation of CRMO with retinal vasculitis is extremely rare but important to recognize. The patient demonstrated clinical response to prednisone and tumor necrosis factor-alpha inhibition (TNF-i). This case reports and unusual presentation of CRMO spectrum disease involving the sternum and sternoclavicular joint with concurrent retinal vasculitis.

Erdheim–Chester disease (ECD) is a rare form of non-Langerhans histiocytosis with deposition of lipid-laden macrophages in numerous organs. A 74-year-old man with a history of coronary artery disease, hypertension, and hyperlipidemia presented with nonspecific symptoms including back pain, nausea, vomiting, vertigo, and left leg pain. A neutrophil-predominant elevated WBC count and a bone biopsy revealing histiocytic proliferation positive for CD68 and CD163 and negative for S100 was noted. FDG PET/CT, MRA, and CTA images were obtained. We review the radiologic hallmarks of ECD and demonstrate the radiologic manifestations of response to combined BRAF and MEK inhibitor treatment.

There are increasing data demonstrating the role of flourodeoxyglucose positron emission tomography with computerized tomography fusion (¹⁸FDG PET-CT) in the diagnosis of large vessel vasculitides, including Takayasu arteritis and giant cell arteritis (Hara et al. 1999; Blockmans et al. 1999; Turlakow et al. 2001]. We report a case of large vessel giant cell arteritis involving the major branches of the aorta as detected on ¹⁸FDG PET-CT. A 56-year-old woman returning to the USA after visiting her native Iraq presented to our rheumatology department with fever of unknown origin (FUO) of 2-month duration, night sweats, and arthralgias. The patient did not have claudication; systolic blood pressure measurements demonstrated a 20-mmHg difference between her arms. Infectious disease, malignancy, and collagen vascular disease workup was unrevealing. Temporal artery and bone marrow biopsies were negative. To exclude FUO of malignancy, ¹⁸FDG PET-CT imaging was performed. The images demonstrated significant ¹⁸FDG uptake (indicating increased metabolic activity) in a circumferential fashion along the aorta and its major braches, including the carotid, subclavian, and common iliac arteries. Contrast-enhanced CT imaging demonstrated wall thickening involving these vessels along with left subclavian vein thrombosis and findings consistent with superficial thrombophlebitis involving the right forearm, wrist, and hand. The combination of laboratory and imaging findings, including the characteristic inflammatory changes involving the large vessel walls as seen on CT, as well as the vessel wall hypermetabolism on FDG PET indicating active inflammation, resulted in the diagnosis of large vessel giant cell arteritis. The patient was treated with high-dose corticosteroids followed by a course of Immuran. Her symptoms resolved and a follow-up FDG PET-CT showed complete resolution of the large vessel hypermetabolism. ¹⁸F-FDG PET-CT can be a useful and noninvasive tool in diagnostic evaluation of FUO by excluding a malignant etiology and providing unexpected information that aids in correct diagnosis.