Gross and histological lesions in the livers of sika deer with particular emphasis on fascioliasis

We performed gross and histological examinations of the livers of sika deer (Cervus nippon yesoensis) in Hokkaido, Japan. Out of 1,381 deer slaughtered for venison production, thickening and dilation of the large intrahepatic bile ducts and Fasciola flukes in the duct lumens were detected in 621 deer (45.0%). Furthermore, 107 non-bile lesions (75 intrahepatic and 32 capsular lesions) were detected during gross examinations. Histologically, the bile duct lesions included chronic proliferative cholangitis, papillary hyperplasia, goblet cell and pyloric gland metaplasia, and periductal fibrosis. Many of the intrahepatic non-bile duct lesions (53/75, 71%) were considered to be Fasciola fluke migration-associated lesions, including two lesion types: necrosis, hemorrhage, and eosinophilic granuloma formation (29 lesions), and lymphoid tissue formation (24 lesions). Lymphoid tissue formation was considered to result from the persistent immune responses against dead Fasciola flukes. An epidermoid liver cyst was found incidentally, which has not been reported in the veterinary literature. In summary, this study demonstrated the predominance of fascioliasis-associated lesions in sika deer livers. The gross and histological lesions caused by Fasciola flukes in sika deer were similar to fascioliasis in other animals. Moreover, we described lymphoid tissue formation as a fascioliasis-associated lesion for the first time. The fact that bile duct lesions (45.0%) had a markedly higher prevalence than fascioliasis-associated parenchymal lesions (53/1,381, 3.8%) indicated that sika deer are a permissive host for fascioliasis. Our results provide information that will aid pathological examinations of sika deer.

Primary intrahepatic squamous cell carcinoma in a sika deer

A white nodule was detected in the liver of a wild female sika deer. The nodule was histologically diagnosed as squamous cell carcinoma (SCC), and it transitioned into a hyperplastic and chronically inflamed intrahepatic bile duct showing Fasciola infection. Therefore, the tumor was demonstrated to have originated from the biliary epithelium of the intrahepatic bile duct. Hyperplastic and chronic inflammatory changes of the biliary epithelium might have contributed the carcinogenesis of the present case, as proposed in human primary intrahepatic SCC cases. To the best of our knowledge, this is the first reported case of primary intrahepatic SCC in an animal.

Peritoneal sarcomatoid mesothelioma in a sika deer

A slaughtered 2-year-old female sika deer (Cervus nippon yesoensis) had diffusely distributed multinodular lesions on the serosal surface of the peritoneal cavity and several nodules in the pleural cavity. Histologically, they were composed of proliferating spindle-shaped neoplastic cells, arranged in a fascicular fashion. The cells in the invasive foci transitioned from a sarcomatoid to an epithelioid appearance. Immunohistochemically, both the spindle-shaped and epithelioid cells were at least focally positive for pancytokeratin, vimentin, calretinin, α-SMA, and desmin. From these findings, the deer was diagnosed with peritoneal sarcomatoid mesothelioma with metastasis to the pleural cavity. To our knowledge, this is the first reported case of peritoneal mesothelioma in a cervid species and the first case of mesothelioma in a sika deer.

Intramedullary spinal cord tumors: significance of associated hemorrhage at MR imaging

Magnetic resonance (MR) images obtained in 35 patients with intramedullary spinal tumors were reviewed. Hypointense areas on both T1- and T2-weighted images were seen within or around eight tumors, all of which were in the cervical cord. Hypointensity at the tumor margin was seen in seven cases. Hypointensity within the tumor was seen in two cases. (One case had both types of hypointensity). In seven surgically confirmed cases, hypointensity at the tumor margin was found to be a relatively firm pseudocapsule, and hypointensity within the tumor corresponded to intratumoral hematoma. All of the tumors with hypointensity were ependymomas at histologic examination. When MR imaging shows an intramedullary tumor with hypointensity at the tumor margin, it is suggestive, but not pathognomonic, of an ependymoma.

[MR measurement of normal brainstem cerebellum and corpus callosum on midsagittal section]

The dimensions of the brainstem, cerebellum and corpus callosum were measured on magnetic resonance (MR) images with sagittal spin-echo sequence. Eighty-two normal adults (average 49.6 years old) were measured. The mesencephalic, pontine or cerebellar diameters and lengths could be measured more accurately and reproducibly than medullary diameter and length. The anterio-posterior diameter of the pons and the cerebellum was 23.2 +/- 1.4 mm and 26.4 +/- 2.5 mm respectively. The length of the pons and the cerebellum was 27.8 +/- 2 mm and 45.8 +/- 3.5 mm respectively. We have observed focal thinning at the body of corpus callosum in 73%. This narrowing is almost unquestionably a normal variant.

MR imaging of the brain in patients with mucopolysaccharidosis

MR imaging of the brain was performed in eight patients with mucopolysaccharidosis (MPS). Two had MPS I S, one had MPS IIA, two had MPS IIB, two had MPS IIIB, and one had MPS VI. In the patients with MPS IIA and MPS VI, T1 and T2 were prolonged in various areas of the cerebral white matter. These findings seemed to correspond with the development of pathologic changes in MPS, such as perivascular pits in the white matter observed on slices of the fixed brain. In the patients with MPS IIA and MPS IIIB, the white matter did not show the proper signal intensity, which suggested that myelination was insufficient and that infiltration or deposition of glycosaminoglycan had occurred; this was consistent with the association of these two types with mental retardation. In the patients with MPS I S, no intracranial abnormalities were detected on MR images. MR imaging of the brain may be used to obtain a differential diagnosis of the various types of MPS, to estimate the extent of mental retardation, and to monitor the progress of this disease.