[Primary malignant melanoma of the parotid gland: anatomico-clinical study. Apropos of a case and review of the medical literature]

Abstract

A 62 yo man presented with an enlargement of the parotid gland that had accentuated over the past ten months. Results of a needle aspiration cytology were interpreted as consistent with an adenocarcinoma. A surgical investigation was decided. Frozen and paraffin sections of superficial parotidectomy specimen disclosed a malignant melanoma. This specimen also contained an intraparotid lymph node which was free of tumor. Cervical lymph node dissection yielded 4 metastatic adenopathies among 15 lymph nodes. A retrospective search for an anterior melanocytic lesion was negative. The final diagnosis was primary malignant melanoma of the parotid gland. Cervical radiotherapy was applied. 7 months later, the patient died of diffuse metastatic involvement in the skin, brain, lungs and liver. No local recurrence occurred. Review of the medical literature revealed the rarity of malignant melanomas of the parotid gland (0.68%). No significant differences concerning clinical data and pathological aspects were noted in so called primary malignant melanoma and secondary malignant melanoma of the parotid gland. Nevertheless, primary malignant melanoma of the parotid gland is a controversial entity. Pathogenesis is discussed on the light of modern concepts of diffuse neuro-endocrine system. Prognosis remains poor, due to a late diagnosis and to an inherent aggressiveness of this type of tumor.