Malignant melanoma arising within tattoos as a risk factor for delayed diagnosis: a case report and systematic review.

Malignant melanoma lesions arising in tattoo pigment pose diagnostic challenges, but current literature lacks quantitative data on delayed diagnosis. This study reports a new case involving multiple melanoma lesions in tattoo pigment, alongside a systematic review of past cases. Our objectives were to evaluate the potential for delayed diagnosis in patients with melanoma lesions in tattoo pigment and its impact on prognosis, comparing tumor characteristics with large-scale melanoma studies. A systematic review was conducted using PubMed and Ovid MEDLINE. Included studies were English-language reports of melanoma lesions in tattoo pigment, identifying new cases via case reports/series. Independent review and discussion resolved discrepancies. The review yielded 37 articles with 42 reports of melanoma lesions in tattoo pigment, totaling 43 cases. Of these, 35 were invasive, with mean and median Breslow thickness of 2.49mm and 0.9mm, respectively, which is higher than in large-scale studies. Patients also had a higher incidence of invasive lesions at diagnosis. The increased Breslow depth and risk of dermal invasion suggest a higher risk for delayed diagnosis and worse prognosis in melanoma arising in tattoo pigment. Further analysis of dermatoscopic differences is needed to improve diagnostic guidelines and avoid delayed diagnosis.