An Oyster Neoplasm of Apparent Mesenchymal Origin

Abstract

A neoplastic disorder was found in 1 of 1,400 oysters (Crassostrea virginica) examined from an area near New Haven, Connecticut. The abnormally large atypical cells characterizing this disease were most abundant in the gill region. Additional neoplastic cells were in hemolymph vessels and sinuses and had invaded the vesicular connective tissue. Mitotic figures were common. Epithelium, muscle, and gonad were not invaded. This neoplasm differed cytologically from all previously described oyster neoplasms, but strongly resembled a neoplastic disease described from the mussel (Mytilus edulis) in Oregon.