Radar-Guided Localization and Resection for Metastatic Nodal and Soft Tissue Melanoma: A Single-Institution Retrospective Study.

BACKGROUND: Radar-guided localization (RGL) offers a wire-free, nonradioactive surgical guidance method consisting of a small percutaneously-placed radar reflector and handheld probe. This study investigates the feasibility, timing, and outcomes of RGL for melanoma metastasectomy. METHODS: We retrospectively identified patients at our cancer center who underwent RGL resection of metastatic melanoma between December 2020-June 2023. Data pertaining to patients' melanoma history, management, reflector placement and retrieval, and follow-up was extracted from patient charts and analyzed using descriptive statistics. RESULTS: Twenty-three RGL cases were performed in patients with stage III-IV locoregional or oligometastatic disease, 10 of whom had reflectors placed prior to neoadjuvant therapy. Procedures included soft tissue nodule removals (8), index lymph node removals (13), and therapeutic lymph node dissections (2). Reflectors were located and retrieved intraoperatively in 96% of cases from a range of 2 to 282 days after placement; the last reflector was not able to be located during surgery via probe or intraoperative ultrasound. One retrieved reflector had migrated from the index lesion, thus overall success rate of reflector and associated index lesion removal was 21 of 23 (91%). All RGL-localized and retrieved index lesions that contained viable tumor (10) had microscopically negative margins. There were no complications attributable to reflector insertion and no unexpected complications of RGL surgery. CONCLUSION: In our practice, RGL is a safe and effective surgical localization method for soft tissue and nodal melanoma metastases. The inert nature of the reflector enables implantation prior to neoadjuvant therapy with utility in index lymph node removal.

There are a variety of tools available to localize melanoma that had spread to deep layers of the skin or lymph nodes that can guide surgeons to the cancer when the tumor cannot be felt. We evaluated a marker that reflects radar signals that has been studied in breast surgery but not in melanoma. The marker was placed in the tumor before surgery and was located during surgery using a handheld probe, guiding the surgeon to the correct location. An advantage of the radar-reflecting marker we studied is that since it is safe to stay in the body, it can be placed ahead of the use of cancer medications and can keep track of the tumor as it responds to treatment. In a review of 23 surgeries in which the radar-reflecting marker was used, there was one case where the marker migrated away from the tumor and one case where the marker was not able to be located. Monitoring or alternative definitive treatment was provided in each of these cases. Overall, we found the marker to be an effective tumor localization tool for surgeons and safe for patients. Other marker options available are unable or less suitable to be placed a long time in advance of surgery due to either technical or safety reasons, so the radar-reflecting marker is especially useful when it is placed in a tumor ahead of medical treatment leading up to planned surgical treatment.

Evaluating the role of level 3 axillary lymph node dissection in metastatic melanoma: Can we predict involvement?

BACKGROUND AND OBJECTIVES: MSLT-2 and DECOG-SLT established that immediate complete axillary lymph node dissection (CLND) did not correlate with an increase in melanoma-specific survival when compared with active ultrasound observation in patients with sentinel lymph node (SLN)-positive disease. After those trials, there was a shift toward performing CLND only for clinically node-positive disease. With these changes, we sought to determine the role of level III axillary lymph nodes in bulky disease and how the use of neoadjuvant therapy may impact the rate of positivity in level III axillary nodes. METHODS: We performed a retrospective chart review on all patients who underwent axillary CLND for cutaneous melanoma by one surgeon at an academic center from 2014 to 2022. These patients underwent CLND based on either having SLN+ disease or having clinically palpable or radiographically bulky disease. RESULTS: Of 95 patients included, there were 7 (7.3%) patients with level III positivity. One was SLN+ (1.0%), while 3 (3.1%) had bulky disease and neoadjuvant therapy, and 3 (3.1%) had bulky disease without neoadjuvant therapy. No preoperative factors were identified that predicted level III involvement. After performing CLND, the patients who had clinically palpable or radiographically bulky disease and neoadjuvant therapy had higher percent necrosis of nodes in levels I and II but not III. At 5 years, overall survival and recurrence-free survival were improved in those without level III involvement (58% and 64%, respectively) when compared to those with level III involvement (41% and 50%), though this was not statistically significant. CONCLUSIONS: Further study may identify better prognostic factors for level III positivity, allowing for the possibility of dissecting only levels I and II or even replacing CLND with targeted node dissections.

A rare case of hidradenocarcinoma with anaplastic and invasive features arising from a nodulocystic hidradenoma.

A 91-year-old man presented with a cutaneous left abdominal mass. The mass was longstanding (over 5 years) and slow-growing. Examination revealed a violaceous, multinodular, and exophytic non-tender mass surrounded by patchy erythema. Excisional biopsy was performed and revealed a nodular and cystic dermal proliferation of predominately basaloid cells with focal duct formation, surrounded by prominent hyalinized stroma. The superficial portion of the mass was identified as a nodulocystic hidradenoma. Along the deep aspect and in association with the benign hidradenoma, sheets of markedly atypical epithelioid cells invaded the surrounding tissue, consistent with malignant transformation. Perineural and lymphovascular invasion were seen among areas with anaplastic features. This case supports that some hidradenocarcinoma originates from benign counterparts, and as such, ample sampling is required to definitively exclude a more sinister diagnosis. Diagnostic, prognostic, histopathological, and molecular characteristics, and current knowledge limitations are briefly discussed.