A melanoma of the skin characterized by the presence of melanoma cells in the dermal-epidermal junction only, without infiltration of the papillary or reticular dermis.
Abnormal melanocytes (cells that make melanin, the pigment that gives skin its color) are found in the epidermis (outer layer of the skin). These abnormal melanocytes may become cancer and spread into nearby normal tissue.
Stage 0 includes: tis, n0, m0. Tis: melanoma in situ. N0: no regional lymph node metastases. M0: no detectable evidence of distant metastases. (from ajcc 6th and 7th eds.)