title: Unsuspected Active Sarcoidosis Diagnosed by 18F-FDG PET/CT During the Search for a Primary Tumour in a Patient with Bone Lesions.
abstract: Sarcoidosis is a systemic chronic inflammatory disease of unknown aetiology, characterised by granulomatous lesions with heterogeneous clinical manifestations affecting multiple organs and tissues. Although the respiratory system is most commonly affected, the disease may also present with bone lesions. We report the case of a 31-year-old woman who presented with low back pain and no history of cancer and who was found to have suspicious lesions involving the entire spine on magnetic resonance imaging (MRI). The patient underwent 18F-fluorodeoxyglucose (FDG) PET/CT to search for a primary tumour and for staging purposes. 18F-FDG PET/CT revealed a pattern of hypermetabolic activity in widespread skeletal lesions and in a single left cervical lymph node. The primary tumour was not found, thus suggesting a haematologic disorder. Subsequent biopsies of a cervical lymph node and of bone tissue from L4 revealed active sarcoidosis with no evidence of cancer. This underlines the importance of considering all alternatives when hypermetabolic lesions are found on 18F-FDG PET/CT. Furthermore, 18F-FDG PET can be very useful to indicate accessible sites for guiding fine-needle aspiration cytology (FNAC).
authors.affiliation: Department of Nuclear Medicine, Fondazione Poliambulanza, Via Bissolati 57, 25100 Brescia, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Caobelli
authors.affiliation: Department of Nuclear Medicine, Ospedali Riuniti, Bergamo, Italy.
authors.forename: Sara Vincenzina
authors.initials: SV
authors.lastname: Gabanelli
authors.affiliation: Department of Internal Medicine, Ospedali Riuniti, Bergamo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Brucato
authors.affiliation: Department of Nuclear Medicine, Fondazione Poliambulanza, Via Bissolati 57, 25100 Brescia, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Pizzocaro
authors.affiliation: Department of Nuclear Medicine, Fondazione Poliambulanza, Via Bissolati 57, 25100 Brescia, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Soffientini
authors.affiliation: Department of Nuclear Medicine, University of Brescia, Brescia, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Giubbini
authors.affiliation: Department of Nuclear Medicine, Fondazione Poliambulanza, Via Bissolati 57, 25100 Brescia, Italy.
authors.forename: Ugo Paolo
authors.initials: UP
authors.lastname: Guerra
keywords: 18F-FDG PET/CT; MRI; Metastatic bone lesion; Sarcoidosis; Uncertain primary