PET scan in clinically suspected paraneoplastic neurological syndromes: a 6-year prospective study in a regional neuroscience unit.
BACKGROUND
The role of PET in the diagnosis of paraneoplastic neurological syndromes (PNS) has previously been reported in retrospective studies, from specialized neuro-oncology units, often selecting patients with positive paraneoplastic antibodies.


OBJECTIVE
To prospectively assess the usefulness of PET in detecting malignancy in patients clinically suspected of having PNS.


METHODS
PET was performed in patients suspected of PNS within 4 weeks of the normal CT body scan. All patients were followed up.


RESULTS
Eighty patients suspected of having PNS underwent PET. 18/80 (23%) were abnormal and suspicious of malignancy. The total number of definite and probable PNS with abnormal PET was 11/18 (61%). The total number of definite and probable PNS with a normal PET was 3/62 (5%). Only 50% of patients with biopsy-proven malignancy were positive for paraneoplastic antibodies. The prevalence of abnormal PET in patients presenting with classical PNS was 41% as opposed to 21% in patients with non-classical PNS. The sensitivity and specificity of PET in diagnosing PNS was 75% and 87% respectively.


CONCLUSIONS
PET is a valuable tool in clinically suspected PNS. Its use should not be restricted to specialized neuro-oncology units or in patients with positive paraneoplastic antibodies. Positive yield is the highest amongst patients with classical PNS.
Department of Neurology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals, NHS Trust, Sheffield, UK. m.hadjivassiliou@sheffield.ac.uk
M
M
Hadjivassiliou
S J
SJ
Alder
E J R
EJ
Van Beek
M B
MB
Hanney
E
E
Lorenz
D G
DG
Rao
B
B
Sharrack
W B
WB
Tindale
D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood; D020274:Autoimmune Diseases of the Nervous System / Q000097:blood / Q000000981:diagnostic imaging* / Q000209:etiology; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006297:Health Services Accessibility; D006757:Hospital Units / Q000600:supply & distribution; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D009422:Nervous System Diseases / Q000000981:diagnostic imaging; D009488:Neurosciences; D020361:Paraneoplastic Syndromes, Nervous System / Q000097:blood / Q000000981:diagnostic imaging* / Q000209:etiology; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
D001323:Autoantibodies