Toluidine blue dye as a breast localization marker.

We compared the efficacy of toluidine blue dye vs methylene blue as a visual marker for breast localizations in vitro and in vivo. In phase 1, the dyes were injected into 10 mastectomy specimens and allowed to diffuse for 24-48 hr. In phase 2, the breasts of four premastectomy patients were injected with the dyes and the dyes were allowed to diffuse for 3 3/4, 12, 24, and 47 hr before mastectomy. In phase 3, the breasts of 18 women in whom 20 breast localizations were performed before excisional biopsy were injected with methylene blue or toluidine blue up to 2 hr 10 min before the biopsy. All excised stained breast tissue was evaluated blindly. The amount of pain associated with injections of the dye was recorded. The 22 women in phases 2 and 3 had had mammograms before, and the parenchymal patterns had been classified according to Wolfe. In the patients injected 3 3/4, 12, 24, and 47 hr before mastectomy, more intense staining with less diffusibility was seen with toluidine blue than with methylene blue. In the 20 localization procedures before excisional biopsy, no difference in intensity of staining or radius of diffusion was seen between methylene blue and toluidine blue with maximal diffusion times of 2 hr 10 min. Breast parenchymal pattern did not correlate with stain intensity or diffusibility. The six patients in whom both methylene blue and toluidine blue were injected and the 18 patients in whom either dye was injected felt less discomfort at the time of injection of toluidine blue than of methylene blue. Our results suggest that toluidine blue causes less discomfort and produces a more intense stain with a smaller diffusion radius than methylene blue regardless of breast parenchymal pattern.