Abstract
Background: Oral malignant melanoma (OMM) is a very rare type of neoplasm. The rarity of these lesions, the degree of malignancy, and the much poorer prognosis than in pigmented types all influence the difficulty of establishing the right diagnosis and, as a result, the ability to initiate treatment. The following case is very characteristic of the first benign clinical appearance of the lesion, which could result in delayed therapy.
Case Report: A 65-year-old woman presented to the Oral Surgery Department of Wroclaw Medical University with a mucosa-coloured lesion found on the hard palate. The excisional biopsy was carried out. The following histopathological and immunohistochemical examination showed amelanotic oral malignant melanoma. The patient was subjected to additional treatment in the Maxillofacial Surgery Department and the Oncology Center of Wroclaw Medical University. Partial maxillectomy was performed as well as subsequent elective neck dissection and irradiation with a bilateral 50 Gy dose. Despite supplementary treatment, the 2-year survival period was observed.
Conclusions: The oral cavity mucosa is an anatomical structure involved by numerous benign and non-suspicious lesions of obvious etiology such as fibroma, epulis, and giant cell tumor. Although its appearance is obvious, early histopathological confirmation of the character is essential for further treatment in case of confirmation of malignancy. As there are very few cases of AOMM diagnosed yearly world-wide, it is very difficult to establish clear criteria for clinical recognition of this type of melanoma. Therefore, it is suggested to take specimens of every pathological lesion in order to identify lesions histopathologically, even though this activity significantly increases the risk of distant metastasis.

Keywords: Amelanotic oral melanoma, positron emission tomography, immunohistochemical staining, maxillary resection, selective neck dissection