Malignant transformation of nevi unlikely in pregnant patients

November 1, 2010

Melanocytic nevi always have the potential to change in size, shape and color regardless of when they first appear in the skin, or the age of the patient. A recent study shows that though some nevi demonstrate dynamic change throughout a pregnancy, there does not appear to be an increased risk of malignant transformation of these nevi, nor is there an association between changing nevi and melanoma.

Key Points

Galati, Romania - Melanocytic nevi always have the potential to change in size, shape and color regardless of when they first appear in the skin, or the age of the patient. A recent study shows that though some nevi demonstrate dynamic change throughout a pregnancy, there does not appear to be an increased risk of malignant transformation of these nevi, nor is there an association between changing nevi and melanoma.

Study details

Results showed that of the 357 nevi located on distended areas of skin, 49 (13.72 percent) were enlarged in diameter (up to 3 mm) between the first and third trimester. At six months postpartum, 38 nevi (77.5 percent) returned to their original dimension at baseline, eight (16.3 percent) remained enlarged and three (6.2 percent) regressed or shrank to a size smaller than baseline measurements.

"Some of the enlarged nevi demonstrated asymmetrical growth, clinically classifying them as atypical nevi. However, none underwent malignant transformation during the pregnancy," Dr. Tatu says.

According to Dr. Tatu, the dynamics of the nevi witnessed upon clinical exam should be correlated with dermoscopic evaluation, especially because in this study, not all of the enlarged nevi demonstrated concomitant relevant dermoscopic changes, and some of the nevi that did not change in dimension exhibited dermoscopic changes.