title: Light and electron microscopic analysis of tattoos treated by Q-switched ruby laser.
abstract: Short-pulse laser exposures can be used to alter pigmented structures in tissue by selective photothermolysis. Potential mechanisms of human tattoo pigment lightening with Q-switched ruby laser were explored by light and electron microscopy. Significant variation existed between and within tattoos. Electron microscopy of untreated tattoos revealed membrane-bound pigment granules, predominantly within fibroblasts and macrophages, and occasionally in mast cells. These granules contained pigment particles ranging from 2-in diameter. Immediately after exposure, dose-related injury was observed in cells containing pigment. Some pigment particles were smaller and lamellated. At fluences greater than or equal to 3 J/cm2, dermal vacuoles and homogenization of collagen bundles immediately adjacent to extracellular pigment were occasionally observed. A brisk neutrophilic infiltrate was apparent by 24 h. Eleven days later, the pigment was again intracellular. Half of the biopsies at 150 d revealed a mild persistent lymphocytic infiltrate. There was no fibrosis except for one case of clinical scarring. These findings confirm that short-pulse radiation can be used to selectively disrupt cells containing tattoo pigments. The physial alteration of pigment granules, redistribution, and elimination appear to account for clinical lightening of the tattoos.
authors.affiliation: Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Boston 02114.
authors.forename: C R
authors.initials: CR
authors.lastname: Taylor
authors.forename: R R
authors.initials: RR
authors.lastname: Anderson
authors.forename: R W
authors.initials: RW
authors.lastname: Gange
authors.forename: N A
authors.initials: NA
authors.lastname: Michaud
authors.forename: T J
authors.initials: TJ
authors.lastname: Flotte
mesh_terms: D001706:Biopsy; D006801:Humans; D007834:Lasers; D008854:Microscopy, Electron; D010860:Pigments, Biological / Q000528:radiation effects*; D012867:Skin / Q000473:pathology / Q000528:radiation effects* / Q000648:ultrastructure; D013653:Tattooing
chemical_list: D010860:Pigments, Biological