6-[F-18]fluoro-L-DOPA positron emission tomography in the imaging of Merkel cell carcinoma: preliminary report of three cases with 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography or pentetreotide-(111In) SPECT data.
OBJECTIVE
Merkel cell carcinoma (MCC) is an uncommon and aggressive cutaneous neoplasm of neuroendocrine origin. Somatostatin receptor scintigraphy (SRS) and positron emission tomography (PET) using 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) have been proposed to stage MCC and to detect early recurrences. As 6-[F-18]fluoro-L-DOPA (FDOPA) is taken up by other neuroendocrine tumors, we speculated that FDOPA-PET could image MCC.


METHODS
FDOPA-PET was performed together with FDG-PET (three patients) and SRS (two patients) in different clinical settings: localization of the primary tumor, staging, and suspicion of recurrence.


RESULTS
Uptake of FDOPA-(18F) by MCC was observed in the two true-positive cases, with an agreement between the results of FDOPA-PET, FDG-PET, and SRS; however, the contrast was lower on FDOPA-PET than on FDG-PET images. In the last patient suspected of recurrence repeatedly on SRS and with inconclusive FDG-PET, FDOPA-PET was negative, and a 12-month follow-up demonstrated a true-negative result.


CONCLUSIONS
MCC takes up FDOPA-(18F). The potential role of FDOPA-PET in its management warrants clarification.
Talbot
Jean-Noël
JN
Médecine nucléaire et Centre TEP AP-HP, Hopital Tenon, Paris, France. jean-noel.talbot@tnn.aphp.fr
Kerrou
Khaldoun
K
Missoum
Filda
F
Grahek
Dany
D
Aide
Nicolas
N
Lumbroso
Jean
J
Montravers
F
F
D000368:Aged; D015266:Carcinoma, Merkel Cell / Q000473:pathology*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005260:Female; D005462:Fluorine Radioisotopes; D019298:Glucose-6-Phosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000378:metabolism; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D005462:Fluorine Radioisotopes; D017481:Receptors, Somatostatin; C043437:fluorodopa F 18; C047515:2-fluoro-2-deoxyglucose-6-phosphate; D013004:Somatostatin; D019298:Glucose-6-Phosphate; D004295:Dihydroxyphenylalanine; C081788:pentetreotide