Abstract

Xanthomas are not neoplasms, but are locally invasive masses of foamy macrophages, multinucleated giant cells, and cholesterol clefts. They are reported in mammals, birds, reptiles, and amphibians. Altered fat metabolism is a common finding. Therapy of cutaneous xanthomas includes surgical resection, although diffuse tissue involvement may result in insufficient tissue to close the defect.

We have identified cutaneous xanthomatous lesions in two eels, a snowflake eel (Echidna nebulosa) and a green moray eel (Gymnothorax funebris). The snowflake eel had bilateral swellings at the angles of the jaw and the Moray eel had a swelling on the top of the head that extended down along the side. The wolf eel (Anarrhichthys ocellatus) was found dead and on gross examination several masses were identified in the mesentery. The lesions in all three of the eels supported numerous acicular clefts (cholesterol clefts), surrounded by multinucleate giant cells, and a scattering of vacuolated macrophages.