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DNA aneuploidy in congenital melanocytic nevi: suggestive evidence for premalignant changes
Abstract:
Nuclei with abnormal (aneuploid) DNA content were detected by flow cytometric analysis in 4 of 39 congenital melanocytic nevi and in 0 of 62 acquired nevi. Three of the 4 nevi with DNA-aneuploidy were greater than 20 cm in their largest diameter. We suggest that DNA aneuploidy is an indicator of a premalignant condition in congenital nevi in cases where histologic examination does not reveal any evidence for malignant melanoma. Cells with abnormal DNA content (aneuploid cells) are not uniformly distributed in giant congenital nevi: in one lesion we observed an area with a high percentage of cells with DNA aneuploidy, areas with a low percentage of aneuploid cells, and parts that were found to be normal by flow cytometric analysis. Nuclear pleomorphism was found histologically in the area with the high percentage of aneuploid cells while the areas with the low percentage of aneuploid cells were histologically normal. Thus, flow cytometry seems to be an additional sensitive method for the detection of nuclear abnormalities that are not always apparent by conventional histology. Increase in the relative amount of growth phase (S-phase cells), indicating elevated proliferative activity, was detected in 6 of 39 congenital pigmented nevi and in 6 of 62 acquired nevi.
Insights
Flow cytometry detected abnormal DNA content (aneuploidy) in congenital melanocytic nevi, suggesting a premalignant condition. This method aids in identifying nuclear abnormalities not always visible with conventional histology.
Area of Science:
- Oncology
- Dermatology
- Genetics
Background:
- Congenital melanocytic nevi (CMN) can rarely transform into melanoma.
- Histological examination is standard for assessing nevus malignancy risk.
- Flow cytometry offers a method to detect cellular DNA abnormalities.
Purpose of the Study:
- To investigate the presence of DNA aneuploidy in congenital and acquired nevi.
- To assess if DNA aneuploidy correlates with nevus size or malignancy risk.
- To evaluate flow cytometry as a tool for detecting nuclear abnormalities in nevi.
Main Methods:
- Flow cytometric analysis of DNA content in nevus cells.
- Histological examination of nevus tissue.
- Measurement of nevus size.
Main Results:
- DNA aneuploidy was detected in 4 of 39 (10.3%) congenital melanocytic nevi, but none of 62 acquired nevi.
- Three of the four aneuploid congenital nevi were larger than 20 cm.
- Areas with high DNA aneuploidy in one giant congenital nevus showed nuclear pleomorphism histologically.
Conclusions:
- DNA aneuploidy may indicate a premalignant state in congenital nevi, especially large ones, even without clear histological signs of melanoma.
- Flow cytometry is a sensitive method for detecting nuclear abnormalities in nevi that may not be apparent histologically.
- Elevated S-phase fraction, indicating increased proliferation, was observed in some congenital and acquired nevi.