The Overlapping Clinicopathological Presentations of Pityriasis Lichenoides and Mycosis Fungoides.

Overview

Pityriasis lichenoides (PL) has traditionally been considered a benign cutaneous disorder with a diverse clinical presentation. This comprehensive literature review challenges that notion by exploring its histopathologic, immunopathologic, and molecular overlap with mycosis fungoides (MF). Through examination of lymphocyte populations, T-lymphocyte clonality, and aberrant immunohistochemical phenotypes, our findings indicate that a subset of PL cases, particularly those exhibiting a loss of pan-T-cell markers (CD2, CD5, CD7), or T-cell clonality, may have a closer association with MF. These findings highlight the need for heightened clinical awareness and surveillance in select PL cases, as early identification of MF may improve patient outcomes.