ABSTRACT: The histology of an external mantle growth in 1 of 500 Modiolus kurilensis from a heavily polluted area of Amursky Bay, Sea of Japan, was described. The growth consisted of subepithelial basophilic mucous cells containing glucosaminoglycans, eosinophilic large-granular cells with proteins and neutral polysaccharides, and mixed (acid + neutral mucopolysaccharides) cell types. Some subepithelial eosinophilic and basophilic gland cells were dividing and seemed to be the source of tumor growth. The mitotic index of growth cells reached 0.5% on some growth sections; however, many mitoses were pycnotic. The emergence of the tumor on the mussel mantle is probably related to a compensatory or regenerative hyperplasia of subepithelial mucous cells.

KEY WORDS: Mussel · Mantle · Hyperplasia · Mucous cells · Mitotic index

Published in DAO Vol. 33, No. 3 (1998) on July 30
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1998