Two cases of non‐hybrid melanoma formation in <i>Xiphophorus nezahualcoyotl </i>Rauchenberger, Kallmann &amp; Morizot

Abstract

Gross and histological evidence is presented to document two novel and distinct cases of non‐hybrid melanomas in wild caught northern mountain swordtails Xiphophorus nezahualcoyotl . During initiation one showed increases in melanin expression from a micromelanophore pattern associated with the sword (sword stripes), and the other showed melanin enhancement associated with the spotted‐side macromelanophore pattern on the flanks of the fish. Both cases have spindle cell type melanomas located in the epidermis, dermis, adipose tissue and underlying muscle in several locations on each fish.