PATHOLOGICAL FINDINGS SUGGESTIVE OF INTERCLONAL STABILIZATION IN A CASE OF CUTANEOUS MELANOMA

Metastatic spread is a complex process based on manyfold interactions of the tumor cells with each other and with the surrounding stroma. In experimental systems tumor cell heterogeneity and presence of various subpopulations which interact with one another to stabilize their rel ative proportions within the population has been shown. Here we report a patient with melanoma, showing morphological evidence of two distin ct tumor cell populations in the primary tumor and in all subcutaneous metastases. By image analysis, both populations were clearly characte rized by minimal nuclear diameter and by nuclear form factor and were demonstrable in each specimen. The fact that these peculiar cell popul ations were present in all melanoma lesions removed from the patient m ight indicate that the populations require the presence of each other and that none of them is metastatically competent on its own.