Melanoma is a malignant tumor of melanocytes and the most threatening skin cancer documenting one of the
highest in mortality rates in comparison to other non-skin cancers due to its potential to metastasize. Although the global incidence of melanoma has increased, the melanoma-related deaths decreased owing to the fact that melanoma is curable under the condition that early diagnosis is made and treatment is undertaken as soon as possible. Patients with primary melanoma developing a second primary melanoma are less common compared to the general population developing the first. Not only is melanoma less commonly found in Thai patients but multiple primary melanomas (MPM) are rarely reported. The present report of a 48-year old Thai male who presented with asymptomatic black patch on the right big toe nail and an atypical mole on the back, both of which were histologically confirmed melanomas. Treatment included amputation of the right big toe and wide excision of melanoma on the back, which cleared the malignancy without recurrence until present. Although MPM are rare in Thais, the authors should be alert in cases displaying multiple moles for the possibility of melanomas. The total body examination, early diagnosis and regular follow-up are important to decrease the mortality rate in melanoma patient.

Keywords: Multiple primary melanoma, Melanoma, Hutchinson’s sign, Dermoscopy, Menzies method