RESUMO
BACKGROUND AND AIM: Tattoo adverse reactions requiring diagnostic evaluation and treatment are becoming more common. The aim of this study was to assess tattoo reactions by 20-MHz ultrasonography referenced to histopathology as a comparative method. MATERIALS AND METHODS: A total of 73 individuals with clinical adverse reactions in their tattoos were studied. Punch biopsies for reference histology were available from 58 patients. The Dermascan C(®) of Cortex Technology, Denmark, was employed. Total skin thickness and echo density of the echolucent band in the outer dermis were measured. Biopsy served for diagnosis and for determination of the level of cellular infiltration in the dermis. RESULTS: In every tattoo reaction studied, the skin affected was found thicker compared with regional control of the same individual (mean difference 0.73 mm). A prominent echolucent band of mean thickness 0.89 mm was demonstrated, primarily located in the very outer dermis but propagating to deeper dermal layers parallel to increasing severity of reactions. The thickness of the echolucent band correlated with the thickness of cellular infiltration determined by microscopic examination, R = 0.6412 (P < 0.001). Special diagnoses such as granulomatous and pseudolymphomatous tattoo reactions showed no distinct characteristics by ultrasound, but mainly displayed themselves by their advanced inflammatory component. DISCUSSION AND CONCLUSION: It is demonstrated for the first time that ultrasound, with histopathology as the comparative method, can quantify the severity of tattoo reactions and non-invasively diagnose the depth of the inflammatory process in the dermis elicited by the microparticulate tattoo pigment, which itself is too minute to be imaged by ultrasound. Preoperative 20-MHz ultrasound scanning is introduced as a potentially useful method to guide therapeutic interventions by surgery and lasers.