Abstract Suprasellar germinomas were identified in
three wild-caught lake whitefish (Coregonus clupeaformis)
from the St. Lawrence River, Quebec, Canada. Histologi-
cally, the three tumors expanded the subarachnoid space
of the ventral surface of the brain immediately adjacent to
the pituitary gland and, in one case, infiltrated the adja-
cent neuropil. These tumors were characterized by nests
and sheets of round cells with a high mitotic rate, sepa-
rated by a scant amount of loose fibrovascular stroma.
The stroma was infiltrated by a moderate number of small
mononuclear cells, including rare CD3-immunoreactive
lymphocytes. This is the first report of intracranial germi-
noma in a fish species.
Key words Germ cell tumor · Suprasellar · Fish Cancer
Introduction
Suprasellar germ cell tumors are neoplasms of gonadal
germ cells which develop at the base of the skull cavity,
right above the sella turcica. The current theory for the
embryological origin of those tumors implicates abnor-
malities in germ cell migration during embryogenesis and
their subsequent transformation into neoplastic cells [3].
The histogenesis and differentiation of extragonadal germ
cell tumors are analogous to those of their gonadal coun-
terparts: pure germ-line tumors are called germinomas,
while differentiated germ cell tumors are divided into em-
bryonic (embryonal carcinoma and mature or immature
teratoma) and extraembryonic (choriocarcinoma and en-
dodermal sinus tumor). Germinomas are histologically
identical to testicular seminoma and ovarian dysgermi-
noma [19, 24].
In man, intracranial germ cell tumors are rare tumors
of children and young adults. They are extremely rare in
animal species and isolated cases have been described in
dogs [23], cows, rabbits, and chicken [22]. Here we de-
scribe the histology and ultrastructure of germ cell tumors
of the germinoma type in three lake whitefish (Coregonus
clupeaformis), a North American species found in cold
and temperate waters, from a population with high tissue
concentrations of environmental contaminants (de La-
fontaine, unpublished) and high prevalence of hepatic tu-
mors [17].
Methods
Lake whitefisch (n = 512) were collected using a fixed fishing gear
installed at Saint-Nicolas (46 43’ N, 71 19’ W), Quebec, Canada,
from 1 September 1996 to 30 October 1996. Fish were killed with
an overdose of tricaine methane sulfonate (MS 222) and a com-
plete postmortem examination was performed. Samples of major
organs, including a transverse section of the brain through the pi-
tuitary, were preserved in 10% buffered formalin for histological
examination. Samples were embedded in paraffin wax, sectioned
at 4 μm and stained with hematoxylin-phloxin-saffron. Additional
formalin-fixed specimens of two tumors were routinely processed
I. Mikaelian · J.-M. Lapointe · Y. de Lafontaine ·
J. C. Harshbarger · R. J. Côté · D. K. Naydan ·
D. Martineau
Suprasellar germinoma in three lake whitefish
(Coregonus clupeaformis)
Acta Neuropathol (2000) 100 : 228–232 © Springer-Verlag 2000
Received: 13 July 1999 / Revised, accepted: 15 November 1999
CASE REPORT
I. Mikaelian · J.-M. Lapointe () · D. Martineau
Canadian Cooperative Wildlife Health Centre
and Centre Québécois sur la Santé des Animaux Sauvages,
Département de Pathologie et de Microbiologie,
Faculté de Médecine Vétérinaire, Université de Montréal,
Saint-Hyacinthe, Québec J2S 7C6, Canada
e-mail: lapoije@medvet.umontreal.ca, Fax: +1-450-7788116
Y. de Lafontaine
St. Lawrence Centre, Environment Canada, Montréal,
Québec H2Y 2E7, Canada
J. C. Harshbarger
Registry of Tumors in Lower Animals,
George Washington University Medical Center,
Department of Pathology, Washington, DC 20037, U.S.A.
R. J Côté
Departement de Pathologie, Hôpital Saint-Luc,
1058 Saint-Denis, Montréal, Québec, H2X 3J4, Canada
D. K. Naydan
Veterinary Medical Teaching Hospital,
Department of Pathology, University of California at Davis,
Davis, CA 95616, USA