Premycotic eruptions.

Virtually any longstanding, recalcitrant inflammatory dermatosis may evolve into a cutaneous T-cell lymphoma. Although several entities within the parapsoriasis group can undergo malignant degeneration, most cases of cutaneous T-cell lymphoma are not preceded by parapsoriasis; a preceding inflammatory dermatosis that is not a parapsoriasis may be much more common. Among the parapsoriasis, lymphomatoid papulosis and large-plaque parapsoriasis and its variant, retiform parapsoriasis, have a variable tendency to undergo malignant degeneration. For any dermatosis deemed to have a significant premalignant potential, a plan of aggressive management with relatively non-aggressive modalities (for example, topical steroids, UVB light, and psoralen plus UVA light) should be considered.