Malignant melanoma in the Sinclair miniature swine: an autopsy study of 60 cases

Sinclair miniature swine spontaneously develop multiple cutaneous melanomas which have the ability to metastasize and regress. This study, based on 60 necropsies, documents the similarity of the pathology of the cutaneous malignant melanomas and the organ distribution of metastasis to human melanoma. The invasive cutaneous melanomas have an intraepidermal component analogous to human superficial spreading melanoma. The pathology of the spontaneous regression, characterized by a series of cellular events beginning with a mononuclear inflammatory infiltrate and leading to depigmentation and fibrosis, is likewise similar to cutaneous regression in human melanoma. Just as with human melanoma,metastasis was correlated with deeply invasive cutaneous tumors. Because of both the biologic and histologic similarity of this animal model to human melanoma, the Sinclair miniature swine should serve as an important resource in continuing the study of melanoma.