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Benign melanocytic lymph node deposits in the setting of giant congenital melanocytic nevi: the large congenital nodal nevus
Author(s) -
Bowen Anneli R.,
Duffy Keith L.,
Clayton Frederic C.,
Andtbacka Robert H.I.,
Florell Scott R.
Publication year - 2015
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.12580
Subject(s) - congenital melanocytic nevus , nevus , melanoma , medicine , melanocytic nevus , pathology , sentinel lymph node , lymph , lymph node , blue nevus , nodal , anatomical pathology , immunohistochemistry , cancer , anatomy , breast cancer , cancer research
Background Benign melanocytic rests are a frequent finding in superficial lymph nodes removed during sentinel lymph node biopsies for melanoma. Whereas the histopathology of these deposits is well understood, very little is known regarding melanocytic lymph node deposits in the setting of giant congenital melanocytic nevi. Methods We analyzed lymph nodes removed from the drainage basin of giant congenital melanocytic nevi in three patients who had developed melanoma within their giant congenital nevi. Results Two of three patients showed widespread, capsular and parenchymal melanocytic deposits in multiple nodes (9 of 11 nodes in one patient and 6 of 8 in the other). Melanocytes were small, non‐mitotically active and resembled those in the associated giant congenital melanocytic nevus. Melanocytes were arranged singly and in small nests ∼0.05 mm in diameter, with some larger sheets up to 1 mm. Nodal melanocytes stained for Melan A and S100 on immunohistochemical evaluation, but showed negative or minimal HMB ‐45 reactivity. Conclusions Evaluation of lymph nodes in the setting of giant congenital melanocytic nevi is complicated by the presence of often numerous, parenchymal melanocytic nevic deposits. Bland cytology and minimal or absent HMB ‐45 staining may be helpful in differentiating these nodal melanocytic nevi from metastatic melanoma. We term this phenomena large congenital nodal nevus.