Piazzalunga et al 2016 — Melanoma Ambiguous Areas, Two Contralateral SNB Cases
Two Italian case reports (General Surgery Unit, Papa Giovanni XXIII Hospital, Bergamo). No ICG used — lymphoscintigraphy (LS) + SNB only. Directly relevant as a melanoma-specific contralateral/ambiguous-drainage comparator, which the vault was previously short on.
Case 1 — verified from full text
M.M., 56M. Midline hypogastric melanoma (Breslow 4.35 mm, ulcerated). Clinically palpable right inguinal node; nothing palpable/on CT on the left. Preoperative LS showed drainage only to the left groin — i.e. exclusively contralateral to the clinically obvious disease. Biopsy of the right node + SNB of the left: both sides positive for metastasis. Completion bilateral inguinal/pelvic dissection: 4/33 nodes positive on the right, 16/16 free on the left (i.e. the left SLN had been the only positive node on that side).
Case 2 — verified from full text
N.F., 59M. Anal melanoma (mitotic index 10/mm², Ki67 70%). Clinically evident right inguinal nodes (FNA-positive); nothing on the left. Preoperative LS showed drainage to both groins (mainly left, lesser right). Left groin SNB found micrometastases (0.4 mm and 0.6 mm) in both biopsied nodes. Completion resection: 4/11 mesorectal, 6/15 right inguinoiliac, 3/12 left inguinoiliac positive. Course complicated by perineal wound dehiscence, healed at 4 weeks with VAC therapy.
Verified verbatim (Discussion)
We also observed that lymphoscintigraphy alone could have missed the clinically palpable metastases at least in one of the two cases. The drainage of the radiotracer was exclusively contralateral to the palpable nodes in one case and mainly contralateral in the other one. This observation supports the hypothesis for which false negative sentinel node biopsies could be due to the changes of the lymphatic flow in the presence of massive lymphatic metastases.
My take (as discussed with the author)
This confirms LS alone can point away from clinically obvious disease — the exact scenario dual/triple-modality mapping (adding ICG) is meant to guard against. The paper doesn’t use ICG at all, so it can’t speak to whether ICG would have changed anything here; it supports the general argument for mapping technique redundancy, not specifically “ICG alone” vs “ICG combined.” Given ICG’s demonstrated high detection rates elsewhere in this vault (see Theme - ICG as SLNB Modality), it’s reasonable to argue ICG would likely have caught what LS nearly missed — but that’s an inference, not something this paper itself tests.
Bibliography leads worth chasing
This paper’s own reference list surfaced two promising, not-yet-acquired sources:
- O’Toole GA, Hettiaratchy S, Allan R, Powell BW. “Aberrant sentinel nodes in malignant melanoma.” Br J Plast Surg. 2000;53:415-417. — title is a near-exact match for this case’s subject matter; high priority to track down.
- Statius Muller MG, et al. “Unpredictability of lymphatic drainage patterns in melanoma patients.” Eur J Nucl Med Mol Imaging. 2002;29:255-261. — parallels Uren, Howman-Giles and Thompson 2003 - Patterns of Lymphatic Drainage from the Skin in Melanoma, worth having both.
- Norman J, et al. Am J Surg 1991;162:432-437 — defined the ~11 cm zone of ambiguous drainage either side of Sappey’s lines; useful anatomical background citation.