Negative 18F-FDG PET and positive CT and MRI findings in multifocal splenic hamartoma

We report our fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18FFDG PET/CT) findings in a 51 years old female presenting with B symptoms, respectively fever, night sweats and malaise, that underwent an 18F-FDG PET/CT examination to exclude underlying lymphomatous disease. Whereas 18F-FDG PET scan findings were negative, CT put to evidence the presence of multiple small lesions suggestive for multifocal hamartoma. On a subsequently performed magnetic resonance imaging (MRI) of the spleen, multiple infracentimetric foci were visualized displaying characteristic findings for hamartoma. During a follow-up period of two years no change in size or characteristics of these lesions occurred.

CONCLUSION: The normal :F-FDG PET/CT findings suggested that, at least in this patient, splenic hamartoma may display a similar :F-FDG avidity when compared to normal splenic tissue. Alternatively, due to the infra-centrimeric size of the hamartoma and spill-over from :F-FDG activity from neighbouring normal tissue, the true 18F-FDG avidity of the hamartomas present might also be overestimated.