Clinical added-value of 18FDG PET in neuroendocrine-merkel cell carcinoma

Abstract

Abstract. Merkel cell carcinoma (MCC) is a rare and highly malignant skin cancer with neuroendocrine differentiation. We studied the potential value of 18 FDG PET in the management of MCC. Eleven patients with MCC were examined by 18 FDG PET and PET-CT for staging purpose (n=4) or for detection of recurrence (n=7). Qualitative and quantitative interpretation of PET studies was performed routinely. 18 FDG PET observations were compared to clinical and radiological findings. In 6 patients, PET findings were also compared to histology. In 7 patients, the 18 FDG tumor uptake was compared to the MCC proliferative activity expressed by the Ki-67 index. 18 FDG PET was contributive in 10/11 MCC patients. In 7 patients, 18 FDG PET detected focal lesions or a disseminated stage of the disease including dermal, nodal and visceral metastases. In 3 patients, a normal 18 FDG PET confirmed complete remission of disease. Most MCC patients exhibited highly 18 FDG-avid sites suggestive of increased glucose metabolism. This imaging pattern was related to a high proliferative activity (Ki-67 index >50%). In 1 patient with a weakly proliferative nodal MCC (Ki-67<10%), a false negative result was yielded by metabolic imaging. In 4/11 patients, 18 FDG PET revealed an unsuspected second neoplasm in addition to MCC. It is concluded that whole-body 18 FDG PET may be useful in the management of MCC patients. However, a normal 18 FDG PET aspect cannot rule out MCC with low proliferative activity.

The predictive value of imaging studies in evaluating regional lymph node involvement in Merkel cell carcinoma

“…3,11,12 More recently, fluorine-18-fluorodeoxyglucose (F-18-FDG)ePET and F-18-FDGePET/CT have shown promise in detecting nodal disease and metastasis and in affecting the staging and management of MCC. 4,5,9,10,[13][14][15][16] Little information exists comparing the sensitivity of these imaging methods with each other and with the gold standard of histopathologic nodal evaluation. We sought to document sensitivity and specificity of various imaging modalities, including CT, MRI, F-18-FDGePET, and F-18-FDGePET/CT, with regard to the primary staging of MCC through histopathologic nodal evaluation.…”

“…[3][4][5][6][7][8][9][10][11] For imaging in primary staging of MCC, the traditional recommendations have included CT, octreotide scans, ultrasonography, and MRI. 3,11,12 More recently, fluorine-18-fluorodeoxyglucose (F-18-FDG)ePET and F-18-FDGePET/CT have shown promise in detecting nodal disease and metastasis and in affecting the staging and management of MCC.…”

Nuclear medicine techniques in Merkel cell carcinoma: A case report and review of the literature

“…Lin et al (23) reported the increased sensitivity of 18 F-FDG PET for detecting MCC recurrence compared with CT. Furthermore, in a study by Belhocine et al (24), 18 F-FDG PET/CT was compared with CT, MRI and bone scan alone in 11 patients. A sensitivity of 92% …”

Carcinome à cellules de Merkel : prise en charge actuelle

“…Les premiers résultats ont fait état d'une sensibilité égale ou supérieure de cette technique par rapport à la tomodensitométrie, mais les études ulté-rieures ont montré un intérêt relatif du fait de la présence de faux positifs et de faux négatifs [28]. La tomographie par émission de positrons au fluorodéoxyglucose a certainement un intérêt en termes de sensibilité de dépistage des métastases, notamment ganglionnaires, par rapport à la tomodensitométrie, mais les résultats demandent à être validés par des études à plus grande échelle [29,30].…”