18F-FDG and 18F-AIF-NOTA-Octreotide PET/CT Confirmed a Rare Case of Cutaneous Merkel Cell Carcinoma With a Solitary Local Nodal Metastasis

Cutaneous Merkel cell carcinoma with local nodal metastasis is a rare entity. A 56-year-old man presented with a nontender left inguinal mass, and ultrasound-guided biopsy of this nodal mass confirmed nodal metastasis with strong neuroendocrine differentiation from cutaneous Merkel cell carcinoma. Staging F-18-FDG PET/CT showed a solitary 3.9 x 6.8-cm hypermetabolic left groin mass with no other suspicious lesions elsewhere. To confirm the patient's eligibility for radical curative treatment, taking into consideration of its neuroendocrine differentiation, a subsequent F-18-AIF-NOTA-octreotide PET/CT was performed, which demonstrated only solitary somatostatin receptor-positive left inguinal mass. The patient underwent radical treatment.