Minimal deviation melanoma (halo nevus variant)

Twenty-eight cases of minimal deviation melanoma (MDM) in the histologic setting of halo nevus formed the basis for this study. Requisites for this study included at least one of the following: a remnant of a halo nevus in a MDM; remnants of both MDM and halo nevus in a common melanoma; and a MDM of Spitz or dermal type, or MDM arising in premalignant dysplasia in which the vertical growth components manifested distinctive cytologic features and cytophilia for lymphocytes. Many of the lesions apparently represented neoplastic progressions involving a population of cells at the dermal-epidermal interface (accretive growth). Some of the lesions qualified as dermal variants and apparently represented neoplastic progressions in a dermal component (interstitial growth). Most examples of MDM in this study were borderline in size (less than 1.00 mm in vertical dimensions). The borderline MDM were interpreted as brief (and in some cases perhaps ephemeral) neoplastic interludes. For the 12 cases with follow-up, there have been no metastases or local recurrences.