Primary Malignant Melanoma of the Parotid Gland Combined 18f-fdgpet/ct and Immunochemical Diagnosis With Literature Review - Primary Malignant Melanoma of the Parotid Gland Combined 18f-fdgpet/ct and Immunochemical Diagnosis With Literature Review - Open Access Pub

Summary Primary malignant melanoma arising from the parotid gland is extremely rare and only sporadic cases have been described. This entity is characterized by delayed diagnosis, poor prognosis and controversial pathogenesis. We report a case of primary malignant melanoma of the parotid gland in a 54-year-old man. The initial diagnosis, made by fine needle aspiration cytology, was malignant tumor without precision. Radical parotidectomy was performed. Diagnosis of primary melanoma of the parotid gland was confirmed by immunochemical analysis revealing positive staining for S-100, HBA-45 and Melan A. Computed Tomography and whole-body 18F-FDGPET/CT image were made to evaluate metabolic and morphologic characteristics of the primary melanoma, to identify potential systemic metastasis at early stage and to exclude primary melanoma elsewhere in the body. The clinical, pathological, immunohistochemical and the role of combined FDG PET/CT features of this lesion are discussed compared to a literature review. DOI10.14302/issn.2574-4526.jddd-16-1322 Primary malignant melanoma (PMM) arising from the parotid gland is extremely rare and only sporadic cases have been described. It is characterized by delayed diagnosis, poor prognosis and controversial pathogenesis. Nevertheless, PMM should be considered in the differential diagnosis of parotid malignancy tumors. We present a 54-year-old man with PMM of the parotid gland confirmed by immunohistochemical findings and integrated 18F-FluoroDeoxyGlucose positron emission tomography/computed tomography(18F-FDG PET/CT) to exclude primary melanoma elsewhere in the body. The clinic-pathological, immunohistochemical and the role of 18F-FDG PET/CT features of this lesion are discussed with a literature review. A 54-year-old man consulted for right retro-auricular mass, painless but pruritic, lasting for two months and growing fast. No significant findings in the medical or surgical history. Physical examination revealed a right retro-auricular mass, fixed to the underlying soft tissues measuring 4 x 3 x 3 cm3. The mass had a fluctuating center and there were signs of inflammation around it. Head and neck examination didn’t show any abnormalities or lymphadenopathy. Oto-Rhino-Lyryngologycal and whole-body examinations were unremarkable. Laboratory studies resulted within normal limits. A short course of antibiotic therapy was initially given without any results. Fine needle aspiration (FNA) cytology revealed parotid malignant tumor without precision. The chest-X ray was normal. Head and neck CT with intravenous contrast