[Show abstract][Hide abstract] ABSTRACT: An osteosarcoma developed in the tarsal joint region involving the distal tibia of a domestic rabbit (Oryctolagus cuniculus). Micrometastases were present in the lungs. Histologically the tumor was composed of ovoid to short-spindle cells with abundant giant cells, producing irregular islands of osteoids. The tumor cells were immunopositive with antiosteocalcin monoclonal antibody, consistent with their derivation from osteoblasts. According to review of 10 published cases, productive osteoblasic osteosarcoma is the most common bone tumor in rabbits, with half of all cases developing in the skull or facial bones.
Preview · Article · Apr 2012 · Comparative medicine
[Show abstract][Hide abstract] ABSTRACT: A male Queensland koala (Phascolarctos cinereus adustus) at Kanazawa Zoological Gardens (Kanagawa, Japan) exhibited paralytic symptoms in the hind limbs. Computed tomography and magnetic resonance imaging revealed a mass on the left ventral side of the 11th to 13th thoracic vertebrae, and the presence of myelitis or edema in the spinal cord. The koala was under anesthesia during the examination and suddenly developed ventricular fibrillation and died. Necropsy revealed a firm flat ovoid hemorrhagic mass on the vertebrae. Following a microscopic examination including immunohistochemistry, the perivertebral mass was diagnosed as B cell lymphoma. Therefore, neoplastic cell infiltration into the spinal cord may cause paralytic symptoms in the hind limbs.
No preview · Article · Mar 2012 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: Androgen-dependent atypical fibromas are benign tumors derived from ganglion-cell-like cells that are particular to Djungarian hamsters (Phodopus sungorus). Masses excised from 2 hamsters were composed of pleomorphic ganglion cell-like cells supported by small to moderate amounts of collagenous matrix. Intracytoplasmic fibrils were present in silver-stained sections, and immunohistochemistry showed that the cells expressed vimentin, androgen receptor, and, in one case, estrogen receptor α. In contrast to previously reported atypical fibromas, these tumors had features of anaplasia and were locally invasive. We diagnosed the tumors as atypical fibrosarcomas and consider them an unusual malignant counterpart of atypical fibroma.
Full-text · Article · Jul 2011 · Journal of the American Association for Laboratory Animal Science: JAALAS
[Show abstract][Hide abstract] ABSTRACT: Prototheca zopfii is divided into three genotypes, one of which, P. zopfii genotype 2, appears to be the main causative agent of bovine protothecal mastitis. However, the difference in pathogenicity between genotypes 1 and 2 has not been well investigated. In the present study, we experimentally infected normal bovine mammary gland with P. zopfii genotype 1 to investigate its pathogenicity. The mammary gland infected with P. zopfii genotype 1 showed no clinical signs. However, the histopathologic features of the infected mammary gland consisted of interstitial infiltrates of macrophages, plasma cells, lymphocytes, and fibroblasts with neutrophils in acinar lumens. Algae were present in macrophages and free in the alveolar lumens and the interstitium. Histopathology of the resultant tissue samples revealed that genotype 1 also induced a granulomatous lesion in the cow teat, similar to the mastitis lesion due to genotype 2.
No preview · Article · Jan 2011 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: Right lateral position (RL) chest radiograms were obtained from 27 heart disease-free rabbits, and cardiac sizes were compared according to body weight (<1.6 vs. > or =1.6 kg) and gender (female vs. male). Significant differences (P<0.05) were observed in RL-long axis (RL-LA) and RL-vertebral heart size (RL-VHS). RL-LA was 4.22 +/- 0.25 and 4.48 +/- 0.3, and RL-VHS was 7.55 +/- 0.38 and 7.99 +/- 0.58, in the <1.6 kg (n=12) and > or =1.6 kg (n=15) groups, respectively. These values should prove useful as new diagnostic indices for cardiac disease in rabbits.
No preview · Article · Apr 2010 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: As ferrets can suffer from a wide variety of cardiac disorders, indicators for detecting cardiac abnormalities on plain chest radiography are necessary. A total of 64 ferrets without heart disease underwent radiography in the right lateral (RL) and ventrodorsal positions (VD), and the lengths of the RL-sixth dorsal vertebra (6th DV), RL- and VD-long axis (LA) and RL- and VD-short axis (SA), RL- and VD- vertebral heart size, VD-length of the eighth costa (LEC) and VD-thoracic width at the eighth thoracic vertebra (8th TV) were measured to establish standard values of normal cardiac appearance. We evaluated statistical differences between genders and ferrets weighing < 1 kg and > or = 1 kg for a total of 38 items. As a result, significant differences (P<0.05) were observed in all items, including some differences that have been reported previously. In particular, the present study established highly accurate standard values for weight differences. Standard values calculated based on the 6th DV and a relational expression obtained by the regression coefficient of the ratio of VD-SA to VD-8th TV, VD-8th TV=2.887 + (0.769 x VD-SA), were considered useful for evaluating normal cardiac morphology in ferrets.
No preview · Article · Mar 2009 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: Mammary tumours from 12 domestic Siberian hamsters (11 females, 1 male) were examined. Histopathology revealed three subtypes: simple adenoma, tubulopapillary carcinoma, and complex carcinoma. In five cases of malignant mammary tumour, focal infiltration into the surrounding fibrous connective tissue was present; however, no invasion of either lymphatics or blood vessels was observed. Apocrine secretion from neoplastic luminal epithelial cells was prominent in all tumours. Expression of oestrogen receptor alpha, progesterone receptor, and androgen receptor was evaluated immunohistochemically in neoplastic epithelial cells. Ten of the 12 tumours were positive for androgen receptor and all were negative for progesterone receptor. Five tumours expressed oestrogen receptor alpha.
No preview · Article · Feb 2009 · Journal of comparative pathology
[Show abstract][Hide abstract] ABSTRACT: The black nodule measuring 1 cm in diameter developed in the base of nail of an 8-year-old Japanese domestic male cat. Histological examination of the excised nodule revealed a granulomatous lesion extending from the epidermis to adjacent bone. The lesion was consisted of diffuse infiltration of macrophages with epithelioid cells and multinucleated giant cells. These macrophages contained a few to numerous yeast-like brown pigmented fungus cells with a spherical shape and dark thick wall. The PCR amplification with universal primers of the 28S ribosomal RNA gene yielded a 628-bp fragment and the direct sequence confirmed that the diagnosis of the lesion was phaeohyphomycosis caused by the pathogenic dematiaceous fungus, Exophiala jeanselmei.
No preview · Article · Jan 2009 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: A total of 90 tumors from 85 domestic hamsters (70 Djungarian hamsters and 15 Syrian hamsters) were examined by histology. In the Djungarian hamsters, 64 neoplastic and 11 non-neoplastic lesions were identified, whereas 14 Syrian hamsters showed neoplastic disease, and one showed non-neoplastic disease. The Djungarian hamsters showed a high prevalence of neoplastic disease, similarly to laboratory Djungarian hamsters. In the Djungarian hamsters, almost all tumors were integumental, whereas hematopoietic tumors were the most common type in the Syrian hamsters. The most common integumental tumors in the Djungarian hamsters were mammary tumors, atypical fibromas and papillomas, and a spectrum of integumental tumors that have not been reported in laboratory Djungarian hamsters were identified. Most mammary tumors occurred in the females, whereas all atypical fibromas were observed in the males. In the Syrian hamsters, plasmacytomas and lymphomas were the most common tumors. The small number of Syrian hamsters in this study may reflect the low prevalence of spontaneous tumors seen in laboratory Syrian hamsters. The mean age of the affected hamsters was 19.8 months, which is relatively advanced. To our knowledge, this is the first comprehensive study of tumors in domestic hamsters.
No preview · Article · Oct 2008 · Veterinary Pathology
[Show abstract][Hide abstract] ABSTRACT: Twenty ferrets with histopathologically diagnosed lymphoma were classified cytomorphologically and immunohistochemically. According to site of origin, multicentric, gastrointestinal, mediastinal and cutaneous lymphomas accounted for 8 (40%), 9 (45%), 2 (10%) and 1 case (5%), respectively. According to the National Cancer Institute Working Formulation (NCI-WF), low-, high- and intermediate-grade lymphomas accounted for 4 (20%), 4 (20%) and 12 cases (60%), respectively. The 4 low-grade lymphomas showed no mitotic figures, whereas all 4 high-grade lymphomas exhibited > or = 3 mitotic figures (median,6). Higher grade thus appears to be associated with a higher number of mitotic figures. Immunohistochemical examination of 18 specimens, excluding 2 insufficient specimens, showed that 16 (88.9%) and 2 (11.1%) lymphomas were of T-cell origin and B-cell origin, respectively. According to the combination of the NCI-WF and immunophenotypes, all 4 low-grade lymphomas (2 multicentric, 1 gastrointestinal, and 1 cutaneous lymphoma) were classified as diffuse small lymphocytic lymphoma of T-cell origin. Of the 12 intermediate-grade lymphomas (6 multicentric, 4 gastrointestinal, and 2 mediastinal lymphomas), 11 were classified as diffuse mixed-cell lymphoma, and 1 as diffuse large cell lymphoma. Of these 11 lymphomas, 2 (both multicentric) were of B-cell origin, 7 (3 multicentric, 3 gastrointestinal, 1 mediastinal) were of T-cell origin, and 2 (1 multicentric, 1 mediastinal) were of unknown cell origin. The remaining 1 lymphoma (gastrointestinal) was of T-cell origin. All 4 high-grade lymphomas (gastrointestinal) were classified as diffuse immunoblastic lymphoma of T-cell origin.
No preview · Article · Sep 2008 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: An 8-year-old, male, mongrel dog developed severe cough and anorexia and died within 3 months. Autopsy revealed an invasive grayish-white mass in the right kidney and multiple nodules in the lungs, thoracic wall, and spleen. Histologically, the renal mass and the other nodules were mainly composed of papillotubular structures lined by oval-to-polygonal pleomorphic cells. The cells were reactive with DBA, PNA, and UEA-1 lectins and positive for vimentin but negative for CD10 and high molecular weight cytokeratin. Because of its histological, histochemical, and immunohistochemical similarities with human collecting duct carcinoma (CDC), a diagnosis of renal collecting duct carcinoma with pulmonary, thoracic, and splenic metastases was established. To our knowledge, this is the first case report of CDC in animals.
Preview · Article · Aug 2008 · Veterinary Pathology
[Show abstract][Hide abstract] ABSTRACT: A 1.5-y-old female Djungarian hamster (Phodopus sungorus) presented with a large subcutaneous mass surrounding the right shoulder. Radiography revealed dislocation of the right humeral articulation and osteolytic lesions of the right scapula. Histologically, the mass was composed of spindle to stellate cells arranged in fascicles interwoven with delicate collagen fibers, and neoplastic cells infiltrated the bone, skeletal muscle, and subcutaneous tissues. Neoplastic cells stained intensely positive for vimentin and negative for S100 protein, neurofilament, and desmin. A minority of neoplastic cells (10% to 20%) stained moderately for smooth muscle actin. The mass was diagnosed as a fibrosarcoma. Although fibrosarcomas are relatively common in dogs and cats, this is the first report of fibrosarcoma in a domestic Djungarian hamster.
Preview · Article · Jul 2008 · Comparative medicine
[Show abstract][Hide abstract] ABSTRACT: In ferrets (Mustela putorius furo), the incidence of hemangiosarcomas is low. Cutaneous hemangiosarcomas in ferrets have been reported as in other organs, but the clinical and diagnostic details are unclear. The present case developed an ulcerative lesion on the dorsal skin of the metatarsal region of the left hindlimb, and the limb was surgically amputated due to exacerbation of the lesion. A diagnosis of hemangiosarcoma was obtained based on histopathological examinations. The examinations revealed proliferation of endothelial celllike pleomorphic cells, which were immunohistochemically positive for Factor YIII-related antigen. The present case achieved long-term survival without recurrence or distant metastasis after six months, and is currently showing good prognosis. We describe details of clinical progress usefulness of immunohistochemical staining, and possibility of good prognosis in a ferret cutaneons hemangiosarcoma.
[Show abstract][Hide abstract] ABSTRACT: A ferret (Mustela putorius furo) with alimentary lymphoma that showed resistance to combination chemotherapywas administered an alkylating agent, Lomustine, as the rescue therapy and achieved complete remission.Lomustine was administered at a dosage of 50 mg/m2 in a total of two doses at 28-day intervals, until remissionwas achieved. No marked toxic effects were observed. Remission duration after rescue therapy was 160 days.It was suggested that Lomustine could be considered a rescue protocol option for lymphoma in ferrets, as wellas in cats and dogs.
[Show abstract][Hide abstract] ABSTRACT: A rare lymphoma that developed in the cecum of a domestic pet rabbit (6 years old, male, crossbred) was examined pathologically. The tumor consisted of proliferating neoplastic lymphoid cells, which were strongly stained with anti-CD79alpha monoclonal antibody. Electron microscopy revealed the tumor cells were composed of rough endoplasmic reticula and/or dilated rough endoplasmic reticula filled with moderately electron-dense material. These findings indicated the present case was rare digestive tract lymphoma originated from B-lymphocytic lineage in the cecum.
No preview · Article · Dec 2007 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: A 6-year-old male cross-breed rabbit ( Oryctolagus cuniculus) was presented with lameness and severe swelling from the right shoulder to brachium. On 16-detector helical computed tomography images of the amputated right forelimb after being fixed in formalin, evident proliferative and destructive lesions of bone were observed. On histologic examination, the tumor was composed of proliferating neoplastic cells that resembled histiocytes, with abundant osteoid production. A large number of multinucleated giant cells were found throughout. This case was diagnosed as osteosarcoma by clinical, radiographic, and histologic findings. This is a rare case report of osteosarcoma in a rabbit consistent with canine predilection sites.
Preview · Article · Oct 2007 · Veterinary Pathology
[Show abstract][Hide abstract] ABSTRACT: A 10-year-old female mongrel cat with back pain was brought to the Nihon University Animal Medical Center. Palpation demonstrated a mass in the back region. Radiography revealed partial destruction of the processus spinosus and the arch of the T8 and T9 vertebrae. On magnetic resonance imaging, the mass was found to have compressed the spinal cord and extended to the outside of the spinal canal. We performed extirpation of the mass, and confirmed that it arose from the spinal canal. Histopathologically, the mass was a malignant peripheral nerve sheath tumor.
No preview · Article · Jul 2007 · Journal of Veterinary Medical Science
[Show abstract][Hide abstract] ABSTRACT: An 8-year-old chipmunk (Tamias sibiricus) showed a mass on the tail root. Histologically, the excised mass showed proliferation of spindle-to-polyhedral cells and abundant multinucleated giant cells, with the production of neoplastic osteoid. Immunohistochemically, neoplastic cells were positive for vimentin and weakly positive for osteocalcin. Osteoid was also positive for osteocalcin. This tumor was diagnosed as a giant cell-type osteosarcoma. This is the first case report of osteosarcoma in a chipmunk.
Preview · Article · Jun 2007 · Veterinary Pathology
[Show abstract][Hide abstract] ABSTRACT: The intra-abdominal tumor developing in the uterus and lung of a domestic Shorthair cat was examined histopathologically and immunohistochemically. The tumor showed a proliferation of both endometrial stromal and smooth muscle cells accompanied by prominent vasculature. There were well-differentiated endometrial glands, and tubuli made up a monolayer of eosinophilic cuboidal epithelium. Immunohistochemically, the spindle-shaped cells and half of the stromal-like cells reacted to caldesmon and desmin antibodies. The neoplastic epithelium expressed AE1/AE3 cytokeratin. Feline endometrial stromal tumor has, to the best of our knowledge, not been reported previously and has smooth muscle and glandular components that are a unique variant to the human counterpart.
Preview · Article · Jun 2007 · Veterinary Pathology