Charcoal suspension tattoo localization for differentiated thyroid cancer recurrence

Background: The high sensitivity of ultrasound and thyroglobulin determination for follow-up of differentiated thyroid cancer allows early detection of nonpalpable recurrences. Intraoperative localization of these small foci in previously dissected necks is a surgical challenge. We describe a new technique for ultrasound-guided tattooing to facilitate excision. Methods: Prospective study of 15 consecutive patients with suspected recurrence of differentiated carcinoma. Whole-body scan after administration of 100 mCi ¹³¹I, performed in 14 cases, was negative in 13. TSH stimulated thyroglobulin averaged 31 ng/ml (<1-182 ng/ml). During ultrasound 19 lesions were discovered in regions already addressed by en bloc neck dissection. Lymph node metastasis was confirmed by cytology in 11 and by washout thyroglobulin in 2. Fine-needle aspiration (FNA) was insufficient for analysis in 1 and was not performed for 5 because of the size (<5 mm). Colloidal charcoal (1-4 ml) was injected under ultrasound, 1-15 days preoperatively. Tolerance, intraoperative charcoal localization, and success of resection were recorded. Results: The injection was well tolerated. Charcoal was found in or just next to 16 lesions (84%). In 1 case it was found several centimeters away. In 1 case, no charcoal was found. In 1 case, hematoma caused by injection impaired surgical exploration. Surgery removed 18 lesions (95%) in 14 patients (93%): carcinoma (16), benign lymphadenitis (2). Conclusions: Ultrasound-guided charcoal tattooing is safe, easy, and well-tolerated for localization of nonpalpable lesions in previously operated necks, with a high rate of success. Excision of these small recurrences remains controversial, however, and may not impact survival or quality of life.