Nucl Med Mol Imaging.  2013 Sep;47(3):205-207.

Unsuspected Active Sarcoidosis Diagnosed by 18F-FDG PET/CT During the Search for a Primary Tumour in a Patient with Bone Lesions

• Caobelli F
• Gabanelli
• Brucato A
• Pizzocaro
• Soffientini A
• Giubbini R
• Guerra UP

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).

Keyword

Sarcoidosis; 18F-FDG PET/CT; Metastatic bone lesion; MRI; Uncertain primary

MeSH Terms

Adult
Biopsy
Biopsy, Fine-Needle
Bone and Bones
Cell Biology
Female
Fluorodeoxyglucose F18*
History
Humans
Low Back Pain
Lymph Nodes
Magnetic Resonance Imaging
Respiratory System
Sarcoidosis*
Spine
Fluorodeoxyglucose F18