Comparative histopathology of gonadal neoplasms in marine bivalve mollusks

Abstract

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. Hundreds of cases were of germ cell origin with hfferent stages of development. They consisted of undifferentiated germ cells that filled individual follicles (stage l ) , were present throughout the gonadal area (stage 2), or had spread to outlying tissues (stage 3). Five cases were of stromal origin. The connective tissue comprising these tumors ranged from vesicular to myxoid to spindle-cell. As these tumors grew, they invaded and destroyed normal follicles. Three cases representing a third histotype appeared to be of both germ cell and stromal origin. Two of these 3 were among 15 Crassostrea virginica recently collected from the Pawcatuck River, Rhode Island, USA. In 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 flbrous. Some neoplastic cells in follicles adjacent to normal ova-bearing follicles were differentiating into spermatocytes. Tumor cells aggressively crossed the follicular basement membrane, invaded the vesicular connective tissue supporting the gill axis, and formed a cystic mass along the lumina1 wall of the branchial vein. The less advanced C. virginica case had a smaller, less aggressive tumor but its basic features were similar. The 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. All 3 of these mixed gonadal-stromal neoplasms are presently diagnosed as gonadoblastomas.

Histopathologic and histochemical biomarker responses of Baltic clam, Macoma balthica, to contaminated Sydney Harbour sediment, Nova Scotia, Canada.

“…Neoplastic changes or histopathologic alterations of gonad cells have been observed in shellfish collected from contaminated areas or exposed to contaminated sediments in the laboratory (14,16,19,21,(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36). The observed lesions ranged from dilation of reproductive follicles in mussel, Mytilus edulis (33), to gonadal neoplasms in soft-shell clam, Mya arenaria (21), and the American oyster, Crassostrea virginica.…”

Disseminated neoplasia in blue mussels, Mytilus galloprovincialis, from the Black Sea, Romania

“…The condition has also been called sarcomatoid proliferative disease (Farley 1969), proliferative atypical hemocytic condition (Lowe and Moore 1978), epizootic sarcoma (Farley et al 1986), sarcomatous neoplasia (Brousseau 1987), transmissible sarcoma (Farley et al 1991) and systemic neoplasia (Moore et al 1991). Regardless the nomenclature, this disorder, apparently of hemocytic origin, is distinguishable from another group of bivalve neoplasia, germinomas (reviewed by Peters et al, 1994) even when these cases become invasive and systemic. Branchial carcinoma of the macoma clam (Farley, 1976) presents some difficulties in distinguishing it from disseminated neoplasia.…”

Arctica islandica: the longest lived non colonial animal known to science

“…Two primary proliferative diseases have been reported in bivalves (for reviews see Peters et al 1994;Barber 2004). The first, a sarcoma, often termed hematopoietic neoplasia (also called leukemia and disseminated sarcoma), predominate in the literature (Poder and Auffret 1986;Brousseau 1987), whilst the second type, gonadal neoplasia, a germinoma, has primarily been reported in the clams M. arenaria and M. mercenaria along the east coast of the USA.…”

“…The first, a sarcoma, often termed hematopoietic neoplasia (also called leukemia and disseminated sarcoma), predominate in the literature (Poder and Auffret 1986;Brousseau 1987), whilst the second type, gonadal neoplasia, a germinoma, has primarily been reported in the clams M. arenaria and M. mercenaria along the east coast of the USA. The Registry of Tumours in Lower Animals (RTLA) contains a report of the second type of neoplasia, gonadal neoplasia, in A. islandica from Rhode Island, USA (Peters et al 1994), but the prevalence and epidemiology of the condition at that location was not reported. However in two other clam species M. arenaria and M. mercenaria the disease occurred more frequently in females and has a relatively small distribution within the overall geographic ranges of the species with prevalence ranging from 5 to 30% depending on location and season of sampling (Barber 2004).…”