Features of sentinel lymph nodes for melanoma may lead to re-diagnosis of the cutaneous primary: an unusual case and review of literature.
Although sentinel lymph-node biopsy is accepted as a reliable method of staging of melanoma, it is not without problems to the pathologist. It has been re-emphasised that aggregates of benign naevus cells are not uncommon. Usually these are easily identified by a combination of their benign cytology and location in the fibrous skeleton of lymph nodes. This case represents a combination of an unusual pseudo-malignant pattern in the primary lesion with unusual morphology of the sentinel lymph node. The latter prompted reassessment of the cutaneous lesion as a benign naevus. Confirmation of the diagnosis as cutaneous melanoma by a positive sentinel-node biopsy was averted only by a careful comparison of unusual features of the putative primary and the sentinel lymph node. This case illustrates the need for a rigorous protocol for pathological assessment of sentinel lymph nodes for melanomas to assure detection of all metastases but also to avoid misdiagnosis and over-treatment. It also supports "benign metastases" as the mechanism underlying at least some melanocytes in regional lymph nodes.
Ramakrishnan
Rathi
R
Department of Histopathology, The Royal Surrey County Hospital, Egerton Road, GU2 5XX, Guildford, Surrey, UK.
Young
Richard
R
Powell
Barry
B
Cook
M G
MG
D000328:Adult; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis; D008198:Lymph Nodes / Q000473:pathology; D008544:Melanocytes / Q000473:pathology; D008545:Melanoma / Q000473:pathology*; D009506:Nevus / Q000473:pathology; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000473:pathology*
D019394:Ki-67 Antigen