Aim: To present a case of a potentially malignant alteration of a blue naevus lesion and draw attention to the importance of researching this lesion, which, if proper diagnosis and therapy are inadequate and apsent, can have life-threatening consequences. Case report: a thirty-six-year-old male presents himself to the Clinic for Maxillofacial Surgery at the Clinical Hospital Center Rijeka due to a sudden, painless swelling in the right preauricular region, measuring 3×2 cm. During the examination, a tumor mass in the right parotid gland was suspected, which is why cytopuncture diagnostics was indicated, showing that it was a metastasis of melanoma. Superficial parotidectomy of the affected gland was indicated and then performed, with an orderly postoperative course. Pathohistological analysis of the removed gland confirmed the diagnosis of melanoma metastasis. A search began for the primary melanoma site, which was never found. From the anamnesis, it was learned that earlier in the same year, the patient underwent surgical excision of a mole on the right side of the temporal region of the face in a private health institution. The pathohistological diagnosis of the excised mole showed that it was a benign blue naevus lesion. In the following years, the patient had regular controls and examinations by various specialists and multidisciplinary oncology teams. In that period, the patient had frequent melanoma metastases throughout his body, for which he underwent more than 20 surgical procedures. The latest findings show that two melanoma metastases were found in the patient’s brain. Conclusions: Although the blue naevus lesion is a frequent efflorescence, the treatment of which is harmless in most cases, new findings point to the potential for malignant alteration of this lesion, based on the increasingly more frequent number of described cases. It is necessary to deepen the research on this potentially dangerous lesion, until it is determined when, in what way and if at all blue naevus can turn malignant, which will allow diagnostics and treatment to be reevaluated and performed more precisely, which will have an exceptional impact on the survival and quality of patients’ lives.