Pityriasis Lichenoides Chronica

The pattern is typical for pityriasis lichenoides chronica including the thick ichthyotic-like parakeratotic scale, pattern of psoriasiform epidermal hyperplasia, unusual tropism of lymphocytes and histiocytes through the more superficial layers of the epidermis accompanied by a superficial lymphocytic purpuric vascular reaction with overall mild lymphoid atypia. Mycosis fungoides can develop in a background of pityriasis lichenoides; however, the lymphoid atypia is insufficient to warrant categorization as mycosis fungoides.

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