A case of lymphomatoid papulosis limited to Becker's melanosis

Regional lymphomatoid papulosis (LyP) accounts for 2-27% of all LyP cases. Several localized dermatoses have been reported in association with Becker's melanosis (BM), e.g. acneiform lesions or lichen planus. Here, we report on regional LyP confined to the area of BM. A 56-year-old man presented with a 1-year history of a steadily increasing number of multiple pruritic red papules developing on the area of BM, which had occurred on his left shoulder during puberty. Histopathological analysis was consistent with regional LyP. Potent topical steroids followed by oral doxycycline did not achieve improvement, while long-term oral bexarotene treatment ameliorated the skin condition. Recently, the proposed entity of 'persistent agmination of LyP' (PALP) has extended the clinicopathological observations of regional LyP. Since PALP remains controversial, a unifying concept of localized LyP and PALP will be discussed.