WNT5A deficiency causes pituitary dysmorphology and ectopic melanotrope differentiation. Immunohistochemistry for prohormone convertase 2 (PC2) marks melanotrope cells, which are normally confined to the intermediate lobe of the pituitary gland. Wnt5a mutant mice contain ectopic melanotropes in a region of dysmorphology adjacent to the intermediate lobe. We show a coronal section from an e18.5 Wnt5a mutant pituitary gland stained with a PC2 specific antibody, developed with the chromagen diaminobenzidine, and counterstained with hematoxylin. The image is artistically arranged as a mirror image duplication with the dorsal aspect of the pituitary facing the outer edges and the ventral aspect towards the center plane. See Potok et al., Developmental Dynamics 237:1006–1020, 2008. © 2008 Wiley-Liss, Inc.