Different types of neoplasia in Crassostrea gigas, Venus verrucosa andMytilus galloprovincialis from the Spanish Coast

摘要

New cases of neoplasia corresponding to three types of neo-plastic condition are described. One out of 22 oysters, C. gigas taken from an oyster farming area in the Ria de Arousa (Galicia,NW Spain) showed disseminated neoplasia (DN). Histological analysis revealed abundant abnormal cells with large (up to 5 mu m) round nucleus and scant cytoplasm infiltrating the connective tissue close to the stomach and in blood sinuses, suggesting inva-siveness; mitotic figures were frequent but other organs appeared free of abnormal cells, suggesting an early stage of disease. DN prevalence in oysters Ostrea edulis cultured in that area is high, thus the possibility of interspecies transmission should be assessed. One out of 25 warty clams Venus verrucosa taken from a bed close to Mao (Balearic Islands, Spain) appeared affected by another type of neoplasia. Histological analysis revealed abnormal cells with large, extremely elongated (up to 10 mu m long) nucleus and scant cytoplasm replacing normal cells of the connective tissue of the visceral mass; mitotic figures were frequent and no abnormal cell was observed in blood vessels. One out of thousands of mussels Mytilus galloprovincialis examined in a histopathological programme ran for 10 years throughout the Galician Rias were affected by ger-minoma. The mussel was hermaphrodite, with some gonad follicles containing either male or female gametes and some other follicles appeared filled with highly basophilic cells, tightly packed, likely deriving from germinal epithelium of the follicles. Mitotic figures were seen in those masses but they were not frequent.