A case of germinoma in a limpet (Patella coerulea) (Patellogastropoda).

Germinoma is a gonadal neoplasm originating from progenitor cells in germinal epithelium. Frequently described in some populations of bivalve molluscs, to our knowledge, germinoma has never been reported in gastropods so far. In this paper we describe the histopathological findings of some atypical cellular masses, originating in the undifferentiated germ cell layer in the male gonads of a limpet (Patella coerulea), whose morphological appearance resembled that of a germ cell tumor. The abnormal, and independent growth with no evidence of maturation of the undifferentiated and atypical germ cells, the limited number of follicles involved (n<10%) and the absence of tissue invasion, supported a diagnosis of Stage 1 germinoma.

Germinoma in razor clam Ensis arcuatus (Jeffreys, 1865) in Galicia (NW Spain).

Germinoma is a gonadal neoplasm originating from progenitor cells in germinal epithelium. Over the last four decades it has been diagnosed in several species of marine bivalve molluscs but most consistently in some populations of Mercenaria mercenaria and Mya arenaria in North America. Tissue sections of gonads from Ensis arcuatus (family Pharidae--superfamily Solenacea), collected in Ría de Vigo (Galicia-NW Spain), revealed germinoma in both males and females. Proliferating, undifferentiated, germ cells, with no evidence of maturation, had formed discrete masses in the walls and lumens of gonadal follicles. This is the first report of germinoma in superfamily Solenacea.

Mixed germ cell tumour of the spinal cord in a young dog.

A spinal cord mixed germ cell tumour was identified in a two-year-old, female Airedale terrier with a history of progressive paraplegia. At necropsy, a discrete pale pink spinal cord mass was identified at the L5 vertebra, which extensively invaded the associated spinal cord segments L6 and L7. Histologically, the tumour was located within the subarachnoid space and invaded the spinal cord. It was composed of three different types of cells: small round cells, forming clusters or islands, similar to germ cells identified in testicular germinomas; large cells with eosinophilic or amphophilic cytoplasm, forming trabeculae; and a third, rarer type of well differentiated epithelial cells, forming acinar or tubular structures. Immunohistochemical examination revealed reactivity to antibodies against alpha-fetoprotein and broad spectrum cytokeratins. The composition, cytological features and immunohistochemical staining of this neoplasm are similar to germ cell tumours previously reported in the suprasellar region and in the eye of dogs.

Suprasellar germinoma in three lake whitefish (Coregonus clupeaformis).

Suprasellar germinomas were identified in three wild-caught lake whitefish (Coregonus clupeaformis) from the St. Lawrence River, Quebec, Canada. Histologically, 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 adjacent neuropil. These tumors were characterized by nests and sheets of round cells with a high mitotic rate, separated 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 germinoma in a fish species.

Rarely occurring spontaneous metastasizing testicular tumors in rats. Histopathologic and ultrastructural features.

Testicular tumors are not uncommon in aging rats. However, metastasis from these neoplasms to several distant visceral organs has not been reported. Testicular tumors were observed in a total of 18 (1.34%) Sprague-Dawley rats out of 1340 males examined. Out of these 18 neoplasms, interstitial tumors were observed in 12 rats, of which 11 were benign and one malignant. Spermatic seminomas were observed in two (0.15%) cases (one benign and one malignant). Both rats with malignant testicular neoplasms were sacrified in extremis. Remaining four tumors were classified as mesotheliomas. Detailed gross, histopathologic and electron microscopic features of primary testicular neoplasms with metastases to several distant visceral organs are described and discussed.

Primary suprasellar germ cell tumor in a dog.

A 5-year-old female Rottweiler was examined because of a history of progressive CNS depression and apparent blindness. Findings included retinal degeneration and cranial nerve deficits as well as pronounced hypercholesterolemia and bradycardia. At necropsy, a 3-cm soft, tan mass was found on the ventral surface of the rostral portion of the brain, encompassing the hypophysis and filling the sella tursica. Histologic examination of tumor sections identified 3 distinct cell types. The location and histologic features of the solitary tumor were most consistent with classification as a primary intracranial germ cell tumor.