Case Overview — Recurrent Truncal Melanoma with Contralateral Axillary SLN
Summary
- Diagnosis: Recurrent cutaneous melanoma, left side
- History: Original melanoma treated with left axillary SLNB approximately 20 years ago
- Current presentation: Recurrence of melanoma on the left side again
- Preoperative imaging: Tc-99m lymphoscintigraphy — activity localised to the right (contralateral) axilla
- Intraoperative technique: ICG fluorescence — visualised the aberrant lymphatic channel running from the recurrence site to the right axillary node in real time
- Intervention: SLNB performed on the right axilla (i.e. contralateral to both the original tumour side and the original SLNB side)
- Context: Tc-99m + ICG dual-tracer is routine standard of care at QVH — this was not a trial/research protocol case
- Central claim (resolved — see Open Questions - ICG Alone vs Complementary Framing): Tc-99m localised the aberrant node preoperatively; ICG’s specific contribution was real-time intraoperative visualisation of the aberrant lymphatic channel itself — anatomical resolution that scintigraphy’s activity map alone could not provide
- Novelty angle: ~20-year latency between the original ipsilateral SLNB and the aberrant contralateral pathway only manifesting at recurrence — no paper in the literature review describes a gap anywhere near this long
Known strength
- Intraoperative NIR imaging is full HD, good quality — the Stryker NIR camera captures of the aberrant lymphatic channel are genuinely good enough to anchor a manuscript figure. This is a strength, not a limitation: most of the literature in this vault (Piazzalunga et al.’s scintigraphy images, older lymphoscintigraphy figures in Uren et al. and Statius Muller et al.) relies on low-resolution nuclear medicine images, not clear real-time optical imaging of the channel itself. Good-quality HD stills/video of the actual aberrant lymphatic pathway would be a genuine visual contribution for SCARE 19 (figure legends) — worth building the figures around this footage rather than treating it as an afterthought.
Fields still needed for SCARE compliance
- Demographics — age, sex, occupation, comorbidities (SCARE 9a)
- Exact timeline — dates of original SLNB, recurrence presentation, current SLNB (SCARE 8)
- Original melanoma details — site, Breslow thickness, original SLNB result (SCARE 9c)
- Current recurrence details — exact site/distance from original scar, Breslow thickness (SCARE 9c)
- Clinical exam findings (SCARE 10)
- Full operative details — ICG product/dose, camera system, incision planning (SCARE 12)
- Follow-up duration and outcome (SCARE 13)
- Histopathology of the right axillary node (SCARE 11a)
- Informed consent statement (SCARE 17)
Closest comparators in the literature
- Uren, Howman-Giles and Thompson 2003 - Patterns of Lymphatic Drainage from the Skin in Melanoma — best quantitative anchor: posterior trunk above waist shows 30% contralateral / 27% bilateral axillary drainage (~3% exclusive-contralateral); also the closest mechanistic analogue on record, a documented case of prior ipsilateral axillary dissection 20 years earlier producing an alternative pathway (to the internal mammary chain, in that instance).
- Statius Muller et al 2002 - Unpredictability of Lymphatic Drainage Patterns — independent, same-era dataset corroborating Uren et al.: 61% of dorsal trunk melanomas show unpredictable drainage.
- Chowdhury et al - Truncal Melanoma Contralateral SLN Drainage Prevalence — same drainage question (truncal melanoma → contralateral SLN), modern cohort; corrected incidence is 1.1% (14/1308) for exclusively contralateral drainage — a narrower definition than Uren/Statius Muller’s “contralateral or bilateral,” which is why the percentages differ by an order of magnitude.
- Piazzalunga et al 2016 - Melanoma Ambiguous Areas, Two Contralateral SNB Cases — closest melanoma-specific case-report comparator, though neither of its cases involves axilla-to-axilla drainage or a decades-prior nodal procedure.
- O’Toole et al 2000 - Aberrant Sentinel Nodes in Malignant Melanoma — checked and set aside: describes a different phenomenon (nodes outside any recognised basin), not aberrant pathway to a normally-located node. Useful only as a one-line terminology contrast in the Discussion.
- Gingerich et al 2017 — now fully verified; closest latency match in the vault outside melanoma (18 years between original ipsilateral axillary surgery and the contralateral finding), plus cites a 43.2% aberrant-drainage rate on repeat SLNB in recurrent breast cancer. Breast cancer, not melanoma, and lymphoscintigraphy-only (no ICG).
Unlike all of these, our case combines a documented prior ipsilateral nodal procedure and a multi-decade latency and ICG’s real-time intraoperative visualisation of the resulting channel, in melanoma specifically — every individual element has a precedent somewhere in this literature, but no single published source combines all of them.