RE: Imaging Features of Hepato-Splenic Amyloidosis at PET/CT

Regarding the imaging of hepatic amyloidosis with PET/CT, we read with interest the case report by Son and colleagues (1) in the Sep-Oct 2011 issue of the Korean Journal of Radiology. A few points need to be discussed with more detail. First, although the enhanced CT scan of the spleen exhibited a decreased and diffuse parenchymal attenuation, this observation was not sufficiently emphasized within the manuscript. The radiological finding of splenic hypoperfusion has been well described in the literature as a marker of systemic amyloidosis, which presents a useful clue when clinical findings fail to determine the proper diagnosis (2). In the case reported by Son and colleagues, if the radiologist had immediately suggested the correct diagnostic hypothesis, the patient would have been directed to have the the appropriate laboratory examinations conducted. Specifically, the abdominal fat aspirate test which would have eliminated the need for the PET/CT scan and a risky invasive procedure such as a liver biopsy.

The PET/CT images revealed a marked and diffuse increase in t 18F-FDG uptake in the enlarged liver. How do the Authors explain this finding considering the diagnosis of the disease which is characterized by the deposition and storage of an amorphous substance including amyloid? Did the compressed hepatic cells and the encased bile duct epithelium increase the glucose metabolism or was the amyloid deposition accompanied by the inflammation due to the infiltration of cells? The authors might offer us an hypothesis about the physio-pathological mechanism causing the 18F-FDG uptake in the amyloidotic liver.