We present, to the best of our knowledge, the first case of a malignan
t, primary plaque-type blue naevus in a 61-year-old male. Two biopsy s
pecimens had been examined within 13 years, and revealed a common and
cellular blue variant as a precursor. Locally invasive growth and regi
onal lymph node swelling were present, but these alone could not confi
rm malignancy before evaluation of all clinical and histopathological
features, as they are known to occur with benign cellular blue neavi.
The recent literature and our case indicate that there is a malignant
potential in every histological and clinical variant of blue naevus.