Melanotic lesions of skin and viscera are common in Sinclair miniature swine. Large exophytic melanomas of the skin invariably regress, and regression may be responsible for melanosis of local and regional lymph nodes and some visceral organs. Malignant transformation and metastasis of cutaneous melanomas are uncommon and primary visceral melanomas were heretofore unrecorded. Described are clinical and light microscopic characteristics of melanomas in 3 miniature pigs: a) one pig with a massive, possibly primary, melanoma of the mediastinum, b) one that died with widespread lymphatic and focal pulmonary metastasis of congenital melanomas of the skin, and c) one in which both a large congenital cutaneous melanoma and associated metastatic melanomas in regional lymph nodes regressed completely.
Bibliographical noteFunding Information:
I Received November 2,1973; accepted January 25,1974. 2 Supported by Public Health Service grants RR00285, RR00390, and RR05006 from the Division of Research Resources. 3 Sinclair Comparative Medicine Research Farm and Department of Pathology, School of Veterinary Medicine, University of Missouri, Columbia, Mo. 65201. Address reprint requests to Dr. Manning, Sinclair Comparative Medicine Research Farm, Route 3, Columbia, Mo. 65201. 4 Department of Dermatology, School of Medicine, University of Missouri. 5 Department of Anatomy, School of Veterinary Medicine, University of Missouri. 6 Sinclair Comparative Medicine Research Farm and Department of Microbiology, School of Medicine, University of Missouri. 7 We thank Mrs. Mary Powell and Mr. Gary Thornhill for technical assistance and Mrs. Dorothy Tumulty for typing the manuscript.