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An unintended consequence of laser tattoo removal in a 29-year-old man was a diagnosis of malignant melanoma, according to a German case report.

The patient had sought laser treatment for a large, multicolored tattoo but refused initial excision of a nevus located within the pigmented area, reported Christian Raulin, MD, PhD, and colleagues from Laserklinik Karlsruhe in Karlsruhe, Germany.

The laser specialists had been unable to fully evaluate potential melanomatous changes in the nevus clinically because of the presence of black ink pigments, they explained online in JAMA Dermatology.

No significant abnormalities were seen on dermoscopy, however, so they proceeded with treatment, using a Q-switched Nd:YAG laser at wavelengths of 532 nm for colored ink and 1,064 nm for black pigment, with energy levels of 1.5 J/cm² and 7.1 J/cm² and spot sizes of 6 mm and 4 mm, respectively.

Because of the size of the tattoo -- extending across the chest and both arms -- numerous sessions were required. After 43 treatments, with response waning, a Q-switched alexandrite laser was substituted using 4.8 J/cm² and a 4-mm spot size.

Throughout more than 7 years of treatments, the laser team repeated its recommendation that the nevus be removed, and finally, in late 2009, after 47 sessions, the specialists told the patient that no more treatments would be given without excision.

He finally acquiesced, and biopsy revealed a superficial malignant melanoma, Clark level 2 and Breslow thickness 0.45 mm.

The patient was unwilling to have a further excision to achieve clear margins, but ultrasound of the lymph nodes and chest x-rays found no evidence of further spread.

"The number of decorative tattoos has been increasing, as has the demand for their removal by laser devices. Traumatic events, such as UV and ionizing radiation, mechanical trauma, persistent inflammatory reactions, and burning, have been discussed as cofactors for neoplasm," wrote Raulin and colleagues.

They concluded that in the future, they would require excision before undertaking laser tattoo removal, noting that an additional problem with a lesion that might be melanoma could be ink contamination of biopsied lymph node tissue.

They also cited 16 other cases in the literature of malignant melanomas developing on the site of tattoos.

In one . Those authors also suggested that laser treatment of melanocytic nevi might actually induce malignant transformation.

Another report noted that potentially on exposure to laser light.

"In general, tattoos should never be placed on pigmented lesions; if they are, the tattoos should not be treated by laser," the authors of the case report cautioned.

In addition, repeated dermoscopic evaluations should be performed throughout the process of removal, they noted.

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