Assessment of capsular melanoma cell deposits in sentinel lymph nodes

Authors


With great interest we read the article by Meier et al.,1 who reported on a scoring system used for risk assessment based on tumor load within the sentinel lymph node (SLN) of patients with cutaneous melanoma. The authors take into consideration 3 prognostic parameters: 1) the tumor penetrative depth (TPD) according to Starz,2 2) the greatest dimension of the largest tumor cell deposit, and 3) capsular involvement, ie, the presence of tumor cells within the capsule of the SLN.

In our opinion, the term “capsular involvement” needs clarification because it includes separate forms: 1) pericapsular or intracapsular lymphangiosis, ie, tumor cells in the lumen of lymph vessels penetrating the nodal capsule; 2) very infrequently, the presence of small groups of tumor cells situated in the vicinity of capsular lymph vessels, which can hardly be distinguished from nevus cells or from lymphangiosis; 3) capsular invasion, ie, partial or complete capsular destruction as a result of the expansion of intranodal melanoma metastasis, finally resulting in 4) capsular breakthrough, ie, further spread in the perinodal tissue. With respect to the assessment of capsular deposits of melanoma cells, only a fair reproducibility even between experienced pathologists was reported.3

We applied the Kaplan-Meier estimate to our collective of 190 SLN-positive patients. Capsular invasion was observed in 19 patients. Of those, 7 had capsular breakthrough. Capsular invasion was confirmed to be a significant prognostic factor (P = .02).

Of our SLN-positive patients, 71 (37%) had lymphangiosis; 7 of them had no further lymphatic metastasis. The presence of lymphangiosis did not significantly influence recurrence-free or overall survival.

Based on our observation, we have concluded that further studies are needed to clarify the prognostic impact of intracapsular lymphangiosis melanomatosa.

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