DNA ploidy of malignant melanoma determined by image cytometry of fresh frozen and paraffin‐embedded tissue

Image analysis of DNA content was performed from single nuclei of melanoma monolayer imprints made from fresh frozen (issue of 14 patients with primary malignant melanoma and 16 patients with local recurrences at the incision site and local or distant metastases. This procedure requires fewer cells and is an advantage when the quantity of tumor available is limited, especially in thin low Breslow depth cutaneous melanomas. Image analysis allowed reproducible measurement of DNA ploidy from 100 cells. The frequency of aneuploidy was similar in primary and metastatic melanomas. Three of 3 patients with euploid primary melanomas showed no evidence of recurrences or meta‐stases, though one died of unrelated disease with short follow‐up. The 4 patients with primary melanoma who developed metastases had aneuploid primaries; two of these patients died of metastatic disease. Three of 4 patients with euploid metastatic tumors were free of disease at last follow‐up, and 1 patient died with stable disease. Nine of 12 patients with aneuploid tumors died of metastatic disease. The frequency of DNA ploidy in the present image analysis study correlated with previous (low cytometry studies. In 9 patients with primary tumors with a Bin‐slow depth greater than 0.75 mm, the. DNA content was also determined in nuclei obtained from formalin‐fixed paraffin‐embedded tissue. The frequency of aneuploidy was higher in fresh tissue (7 of 9) as compared with paraffin‐embedded tissue of the same cases (4 of 9).