You are here:
COMPARATIVE HISTOPATHOLOGY OF GONADAL NEOPLASMS IN MARINE BIVALVE MOLLUSCS
Citation:
Peters, E., P. Yevich, J. Harshbarger, AND G. Zaroogian. COMPARATIVE HISTOPATHOLOGY OF GONADAL NEOPLASMS IN MARINE BIVALVE MOLLUSCS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/284, 1994.
Description:
Comparative histology of gonadal neoplasms in 14 marine bivalve species or hybrids from 5 countries described in the literature and/or archived in the Registry of Tumors in Lower Animals (RTLA), Washington, DC, USA, revealed 3 basic histotypes. undreds of cases were of germ cell origin with different stages of development. hey consisted of undifferentiated germ cells that filled individual follicles (stage 1), were present throughout the gonadal area (stage 2), or had spread to outlying tissues (stage 3). ive cases were of stromal origin. he connective tissue comprising these tumors ranged from vesicular to myxoid to spindle-cell. s these tumors grew, they invaded and destroyed normal follicles. hree cases representing a third histotype appeared to be of both germ cell and stromal origin. wo of these 3 were among 15 Crassostrea virginica recently collected from the Pawcatuck River, Rhode Island, USA. n the most advanced case, basophilic hypertrophied neoplastic germ cells were rapidly proliferating along the walls of gonadal follicles and the ducts that extended into the mantle, while the central region of the tumor mass was densely fibrous. ome neoplastic cells in follicles adjacent to normal ova-bearing follicles were differentiating into spermatocytes. umor cells aggressively crossed the follicular basement membrane, invaded the vesicular connective tissue supporting the gill axis, and formed a cystic mass along the luminal wall of the branchial vein. he less advanced C. virginica case had a smaller, less aggressive tumor but its basic features were similar. he third case similar in composition, pattern, and behavior was in a C. gigas that had been collected during the 1960s from the Willapa Bay, Washington, USA, and had originally been interpreted as a fibroma. ll 3 of these mixed gonadal-stromal neoplasms are presently diagnosed as gonadoblastomas.