Background: Solitary pigmented melanocytic lesions of the oral mucosa are sometimes presented asymptomatically. Therefore, the patient does not realize their presence. To establish a diagnosis is challenging since there are similarities with other lesions. Once pigmented lesions on the oral mucosa are found, we need to do a proper diagnosis pathway to rule out the possibility of missing the detection of a malignant lesion. This report presents a case of pigmented oral mucosa located on the palatal and gingival mucosa that had to raise the suspicion to malignant pigmented lesion.