Primary and Metastatic Melanoma With NTRK Fusions

In this study we report that nonspitzoid metastasizing melanomas of adults may also harbor NTRK fusions and that NTRK expression can be immunohistochemically detected in these tumors. Of 751 melanomas analyzed by next-generation sequencing, 4 metastatic melanomas were identified with NTRK fusions, 3 involving NTRK1, 1 involving NTRK2. They occurred in 3 women and 1 man. Two of the corresponding primary tumors were from the trunk, 1 from an extremity and 1 tumor arose in anal skin. One primary tumor displayed features of superficial spreading melanoma and 3 were nodular melanomas. All tumors were cytologically characterized by the presence of large epithelioid melanocytes. All tumors were immunoreactive with anti-Trk antibody. Next-generation sequencing documented that the NTRK1 fusion partners included TRIM63, DDR2, and GON4L. One tumor harbored an NTRK2-TRAF2 fusion. Thus, our findings document that NTRK kinase fusions can occur in nonspitzoid metastasizing melanomas of adults. The presence of an NTRK family fusion in these tumors may provide a therapeutic opportunity in a small subset of patients with metastatic melanoma.

Source: The American Journal of Surgical Pathology - July 12, 2018 Category: Pathology Tags: Original Articles Source Type: research