OVERVIEW 
The Registry of Tumors in Lower Animals facilitates the study of 
neoplasms and related disorders in invertebrate and poikilotherraic ver¬ 
tebrate animals by serving as a specimen depository, a diagnostic cen¬ 
ter, an information center, and a research group. 
Two hundred thirty-nine accessions were entered into the Registry's 
permanent collection in 1977. As shown in Table I, slightly over one- 
half were neoplasms which occurred, in decreasing numbers, in bivalve 
mollusks, bony fish, amphibians, reptiles, and one shark. 
Among the many interesting and significant cases received was an oys¬ 
ter contributed by John A. Couch (RTLA 1599) with both a Dermocystidium 
marinum infection and the condition widely interpreted as a hematopoietic 
neoplasm characterized by a diffuse infiltration of small, unassociated, 
uniform, rapidly proliferating cells. This case, coupled with "Dermo" 
only cases and "hematopoietic neoplasm" only cases, would seem to pro¬ 
vide conclusive evidence that the populations of proliferating, infil¬ 
trating cells known from at least six bivalve species are hematopoietic 
neoplasms rather than a stage of Dermocystidium marinum as once proposed. 
Other mollusks with neoplasms included Australian rock oysters from 
Peter H. Wolf with mantle papillomas (RTLA 1608-1614, 1795); American 
oysters from Sara V. Otto with hematopoietic neoplasms (RTLA 1749, 1750, 
1752-1754, 1757-1761, 1765), undifferentiated sarcomas (RTLA 1763, 1764), 
a germinoma (RTLA 1748), and cryptic adenomatous hyperplasias of the man¬ 
tle (RTLA 1751, 1755, 1756, 1762); European flat oysters from Paul van 
Banning with hematopoietic neoplasms (RTLA 1808, 1809); a mussel from 
David J. Alderman with a hematopoietic neoplasm (RTLA 1833); a scallop 
with a possible hematopoietic neoplasm from Robert S. Brown (RTLA 1834); 
and, soft-shell clams from Paul P. Yevich with germinomas from the Sears- 
port, Maine, oil spill site (RTLA 1694-1703). With regard to soft-clam 
germinomas, we recently found Intranuclear virus-like inclusions in the 
tumor cells and Dr. Sing Chen Chang, the Registry's Electron Microscopist, 
is attempting to verify their viral nature. Thus, these germinomas may be 
caused by a virus with possible activation and/or enhancement by stress 
from petroleum hydrocarbons rather than by direct chemical carcinogenesis. 
Mollusk accessions containing basophilic cytoplasmic inclusions, in¬ 
cluded soft-shell clams (RTLA 1620-1640), a hard-shell clam (RTLA 1766), 
and American oysters (RTLA 1735, 1736) from Sara V. Otto; mussels from 
Paul P. Yevich and Carolyn A. Barszcz (RTLA 1741-1743); and, a thin tellin 
from James S. Buchanan (RTLA 1810). These inclusions have recently been 
found to be very widespread and to represent infections by procaryotic 
organisms such as chlamydiae, rickettsiae, and possibly mycoplasmas. 
One possible shark neoplasm was received from S. Gruber, W. Riemer, 
and M. Michael Sigel (RTLA 1836). The lesion was either an adenoma or 
hyperplasia of probable thyroid origin in a nurse shark. Lack of a 
definitive diagnosis was partly due to an unfamiliarity with the normal 
histology. 
