Effectiveness of preoperative ultrasound-guided charcoal tattooing for localization of metastatic melanoma

Purpose: Excision of metastatic lesions is an important treatment strategy in patients with malignant melanoma, both at the initial diagnosis and upon recurrence. Since nonpalpable lesions cannot be easily visualized in the surgical field, we evaluated the effectiveness of ultrasound (US)-guided tattooing using a charcoal suspension for the localization of nonpalpable metastatic lesions of malignant melanoma. Methods: Between November 2009 and June 2019, we retrospectively reviewed 65 nonpalpable lesions in 29 patients with malignant melanoma who underwent preoperative US-guided tattooing using a charcoal suspension for histologically confirmed or suspected metastases. The characteristics of the tattooed lesions were analyzed. The effectiveness of the procedure was evaluated based on the detection rate in the surgical field and the presence or absence of residua on postoperative follow-up US. Procedure-related complications were also analyzed. Results: Of 65 lesions, 33 (50.8%) were histologically confirmed as metastases before the tattooing procedure, while the other 32 were suspected of being metastases based on imaging studies. The mean lesion size was 9.8 mm (range, 1.3 to 24.4 mm). The final pathology revealed metastases in 59 lesions (90.8%), including lymph node (n=51), muscle (n=5), and in-transit (n=3) metastases. Sixty-one lesions (93.8%) were successfully detected intraoperatively and removed without residua on follow-up US. Four residual lesions were removed after repeated localization (n=2) or by intraoperative US (n=2). No relevant complications were noted. Conclusion: Preoperative US-guided tattooing localization can safely and effectively delineate nonpalpable metastatic melanoma lesions to aid in successful surgical excision.