Photomicrograph Showing Melanoma on a Fin of a Brown Bullhead

Photomicrograph showing a melanoma on a fin of a brown bullhead fish. In the upper right-hand part is normal skin (epidermis). The epidermis has large clear cells and a layer of normal melanocytes along the basement membrane of the epidermis which is where they normally are located. Most of the rest of the tissue is composed of neoplastic melanocytes that invade up into the epidermis as well as into the dermal and subdermal areas.