Christine G. Lian, MD

A study led by Christine G. Lian, MD, BWH Department of Pathology, suggests that the presence of 5-hydroxymethocytosine on biopsied sentinal lymph node cells might be a possible diagnostic marker for distinguishing between a benign nodal nevi and micrometastatic melanoma cells.

Benign nodal nevi present a distinct diagnostic challenge. Appearing similar to metastatic melanoma cells, largely because they are derived from the same cell lineage, they confound several diagnostic techniques and increase the chance of false positive results.

The researchers studied three biopsy sample groups from BWH Pathology archives. The first group consisted of 18 confirmed cases of metastatic melanoma, the second of 10 cases of benign nodal nevus cells, and the third of two controversial cases in which the diagnosis was equivocal. The samples were then stained to test for the presence of 5-hydroxymethocytosine, the absence of which is thought to be a putative epigenetic marker with its loss in melanoma.

George F. Murphy, MD

Lian and colleagues found that among the melanoma group, all samples failed to detect 5-hydroxymethocytosine, while every sample in the nevus group had positivity of it, as did both samples in the equivocal group.

“These findings are in agreement with our other efforts to study 5-hydroxymethocytosine, and thus contribute to the mounting evidence for the validity of this diagnostic procedure,” said George F. Murphy, MD, director, BWH Program in Dermatopathology, co-corresponding study author.

The study was published online August 1, 2014 in Modern Pathology.