Rhabdomyosarcoma of the tongue in a neonatal calf.

A newborn male Holstein calf developed a nodular enlargement at the tip of the tongue. Histopathological examination of the mass revealed predominant proliferating small, round, spindloid or polygonal neoplastic cells with scattered myoblast- and myotube-like cells and multinuclear giant cells. Phosphotungstic acid haematoxylin staining revealed cytoplasmic cross-striations in a few neoplastic cells. Neoplastic cells were immunopositive for vimentin, desmin, myoD1, myogenin, myoglobin and α-smooth muscle actin. The mass was diagnosed as embryonal rhabdomyosarcoma. To the best of our knowledge, this is the first reported case of bovine congenital lingual rhabdomyosarcoma, which is rare in animals.

Wavy changes in the whiskers of domestic cats are correlated with feline leukemia virus infection.

BACKGROUND: Feline leukemia virus (FeLV) is a retrovirus with global impact on the health of domestic cats and is usually examined by serology. In our daily clinical practice, we noticed that cats infected with FeLV often possess wavy whiskers (sinus hairs on the face). To investigate the relationship between wavy whiskers (WW) and FeLV infection, the association between the presence or absence of wavy changes in whiskers and serological FeLV infection was examined in a total of 358 cats including 56 cats possessing WW, using the chi-square test. The results of blood tests from 223 cases were subjected to multivariate analysis (logistic analysis). Isolated whiskers were observed under light microscopy, and upper lip tissues (proboscis) were subjected to histopathological and immunohistochemical analyses. RESULTS: The prevalence of WW was significantly correlated with FeLV antigen positivity in the blood. Of 56 cases with WW, 50 (89.3%) were serologically positive for FeLV. The significant association between WW and serological FeLV positivity was also confirmed by multivariate analysis. In WW, narrowing, degeneration, and tearing of the hair medulla were observed. Mild infiltration of mononuclear cells in the tissues, but no degeneration or necrosis, was found. By immunohistochemistry, FeLV antigens (p27, gp70 and p15E) were observed in various epithelial cells including the sinus hair follicular epithelium of the whisker. CONCLUSIONS: The data suggest that the wavy changes in whiskers, a unique and distinctive external sign on a cat's face, were associated with FeLV infection.

Comparison of Characterization in Two-Dimensional and Three-Dimensional Canine Mammary Gland Tumor Cell Models.

Background: Canine mammary gland tumors can be used as predictive models for human breast cancer. There are several types of microRNAs common in human breast cancer and canine mammary gland tumors. The functions of microRNAs in canine mammary gland tumors are not well understood. Methods: We compared the characterization of microRNA expression in two-dimensional and three-dimensional canine mammary gland tumor cell models. We evaluated the differences between two- and three-dimensional cultured canine mammary gland tumor SNP cells by assessing microRNA expression levels, morphology, drug sensitivity, and hypoxia. Results: The expression of microRNA-210 in the three-dimensional-SNP cells was 10.19 times higher than that in the two-dimensional-SNP cells. The intracellular concentrations of doxorubicin in the two- and three-dimensional-SNP cells were 0.330 ± 0.013 and 0.290 ± 0.048 nM/mg protein, respectively. The IC50 values of doxorubicin for the two- and three-dimensional-SNP cells were 5.2 and 1.6 µM, respectively. Fluorescence of the hypoxia probe, LOX-1, was observed inside the sphere of three-dimensional-SNP cells without echinomycin but not in two-dimensional-SNP cells. The three-dimensional-SNP cells treated with echinomycin showed weak LOX-1 fluorescence. Conclusion: The present study showed a clear difference in microRNA expression levels in cells cultured in a two-dimensional adherent versus a three-dimensional spheroid model.

Case report: Diagnosis and treatment of pulmonary choristoma in a newborn calf.

A 4-day-old female Holstein calf presented with a large-sized, protruding mass in its back, at birth. Radiography identified the deformed spinous process in the second and third lumbar vertebras, suggesting spina bifida. Ultrasonography of the back mass revealed anechoic bronchi-like structures and large vessels with rich blood flow running parallel within the homogenous echogenic mass's parenchyma. Doppler ultrasonography also revealed pulsatile vessels entering into the deeper side of the transverse process of the lumbar vertebras at the right-sided base of the protruding mass. These imaging results were helpful for surgical planning, in which a large arterial vessel was sutured at the right-sided mass's base, followed by resection of the mass itself. The mass's resection could be carried out according to the planned surgical procedure, though its invasion was too deep to be resected completely. Histopathology for the resected specimens revealed that the mass mainly had lung-tissue-like structures comprised of bronchi-, bronchiole- and alveoli-like structures, and large vessels, allowing the diagnosis of pulmonary choristoma. Doppler ultrasonography could contribute to the differentiation between the bronchi-like tubular structure and the large arterial vessels on the same images, aiding diagnosis of this disease.

A case of malignant melanoma, a possible primary site in the digit, with systemic metastasis in a mini-Rex.

We report a case of systemic metastasis of malignant melanoma in a mini-Rex (Oryctolagus cuniculus). The animal presented with lameness of the right hind limb, swelling of popliteal lymph node, and a black mass on the first digit. Paralysis of hindlimbs and forelimbs, dysuria, and dysphagia progressed over time, and the rabbit died on day 35 from the first visit. At necropsy, many black lesions were observed in multiple organs including the marrow of most bones. Histopathologically, the tumor cells had highly atypical nuclei of various sizes and an abundant eosinophilic cytoplasm, and some cells contained melanin granules. These cells were positive for PNL2 and S-100, melanoma markers, by immunohistochemistry. This is the first report of malignant melanoma in a mini-Rex with severe malignancy and systemic metastasis including the bone marrow.

Expression of L-type amino acid transporter 1 in canine and feline intracranial tumors.

L-type amino acid transporter 1 (LAT1) is upregulated in various malignant tumors in humans. LAT1 expression correlates with the grade of cancer and prognosis. LAT1 is responsible for the supply of many essential amino acids to cancer cells. Inhibition of LAT1 reduces the amino acids that enter the cell and inhibits cancer cell growth. Therefore, novel anticancer drugs targeting LAT1 have attracted much attention in recent years. In this study, to explore the applicability of using LAT1 expression in intracranial tumors as a prognostic factor and therapeutic target, we investigated the expression of LAT1 in surgically resected primary and secondary intracranial tumor tissues from dogs and cats. Immunohistochemical analysis of LAT1 was performed on intracranial tumor tissue from 14 dogs and 3 cats. Primary intracranial tumors were seen in 10 dogs and included meningiomas, histiocytic sarcomas, pituitary tumors, and gliomas, and 9 out of 10 cases were positive for LAT1. Primary intracranial tumors were seen in 2 cats and included meningioma and lymphoma; both cases were positive for LAT1. Secondary intracranial tumors were positive for LAT1 in 3 out of 4 cases in dogs and 1 out of 1 in cats. Since the majority of intracranial tumors in dogs and cats were positive for LAT1, immunostaining for LAT1 is expected to be a prognostic indicator and therapeutic target in the future.

Case Report: Ultrasonography and Magnetic Resonance Imaging of Anterior Segment Dysgenesis in a Calf.

This study includes diagnostic efficacy of the antemortem, combined use of ultrasonography and magnetic resonance imaging (MRI) for the diagnosis of anterior segment dysgenesis. A 7-day-old male Holstein calf presented with progressive unilateral exophthalmos associated with enlargement of the right eyeball soon after birth. Ultrasonography of the enlarged right eyeball showed (1) a 2-cm-thick echogenic parenchymal lesion filling the anterior region of the right eyeball, (2) excess accumulation of the anechoic vitreous humor, and (3) absence of the lens structure. Antemortem examination using T2-weighted and fluid-attenuated inversion recovery MRI revealed a thickened, hyperintense anterior lesion and absence of the lens structure. These imaging findings were suggestive of anterior segment dysgenesis. Antemortem imaging showed no abnormalities other than the abnormal structure and size of the right eyeball; therefore, enucleation of the right eye was performed, which allowed intact healing without suppuration. Ocular ultrasonography enhanced the diagnostic accuracy due to the characteristic ultrasonographic findings of a thickened anterior lesion and absence of the lens structure in the eyeball, suggestive of anterior segment dysgenesis.

Detection of squamous cell carcinoma of presumed pancreatic origin and its metastasis in a spotted seal (Phoca largha) using ultrasonography and computed tomography.

A 21-year-old female spotted seal (Phoca largha), with a swollen abdomen, had a five-month history of anorexia and vomiting. Ultrasonography revealed an extended mass with central necrotic foci in the right cranial abdomen. Computed tomography revealed an abdominal mass with a low-density central lumen and a pulmonary nodular lesion. Cytology of an abdominal specimen collected through fine-needle aspiration indicated a malignant tumor with round, atypical cells with large nuclei. Three days after diagnosis, necropsy revealed a 10-cm large, solid, whitish mass in the pancreatic parenchyma and multiple small nodules in the liver, spleen, mesentery, lungs, and mediastinal lymph nodes. Histopathological analysis showed prolific neoplastic cells with marked atypia and occasional keratinization. Immunohistochemistry revealed that the neoplastic cells were positive for cytokeratin AE1/AE3 antibody. Thus, the seal was diagnosed with squamous cell carcinoma, of presumed pancreatic origin, which had metastasized to multiple organs.

Ophthalmic findings in a septic calf with the concurrent exhibition of meningitis and endophthalmitis.

The aim of this study was to evaluate the impacts of ophthalmic findings obtained from both macroscopic examination and ocular ultrasonography when diagnosing bovine endophthalmitis. A newborn crossbreed (Japanese black and Holstein breeds) calf was suspected of visual impairment and central nervous system (CNS) symptoms, such as decreased activity and weak drinking performance. This calf was found to display macroscopic signs, such as clouded lens, convergent strabismus, and horizontal nystagmus, in both eyes. On ocular ultrasonography of both eyes, a V-shaped, thickened, hyperechoic structure was present in the anechoic vitreous humors, indicating retinal detachment. The animal died 4 days after the examination. Sepsis was evident in this case, as Escherichia coli was isolated from multiple organs. The autopsy and histological examination revealed meningitis, encephalitis, and secondary hydrocephalus in the CNS, and endophthalmitis and retinal detachment in both eyes. In this case, the ophthalmic findings did not provide definitive evidence for a diagnosis of endophthalmitis. However, this study indicated that retinal detachment might be an ultrasonographic finding that is suggestive of bovine endophthalmitis.

Unique histological features of the tail skin of cotton rat (Sigmodon hispidus) related to caudal autotomy.

Caudal autotomy in rodents is an evolutionarily acquired phenomenon enabling escape from predators, by discarding the tail skin after traumatic injuries. The histological mechanisms underlying caudal autotomy seem to differ among species. Cotton rats (Sigmodon hispidus), which are important laboratory rodents for human infectious diseases, possess a fragile tail. In this study, we compared the tail histology of cotton rats with that of laboratory rats (Rattus norvegicus), which have no fragility on their tail, to elucidate the process of rodent caudal autotomy. First, the cotton rats developed a false autotomy characterized by loss of the tail sheath with the caudal vertebrae remaining without tail regeneration. Second, we found the fracture plane was continuous from the interscale of the tail epidermis to the dermis, which was lined with an alignment of E-cadherin+ cells. Third, we found an obvious cleavage plane between the dermis and subjacent tissues of the cotton-rat tail, where the subcutis was composed of looser, finer, and fragmented collagen fibers compared with those of the rat. Additionally, the cotton-rat tail was easily torn, with minimum bleeding. The median coccygeal artery of the cotton rat had a thick smooth muscle layer, and its lumen was filled with the peeled intima with fibrin coagulation, which might be associated with reduced bleeding following caudal autotomy. Taken together, we reveal the unique histological features of the tail relating to the caudal autotomy process in the cotton rat, and provide novel insights to help clarify the rodent caudal autotomy mechanism.

Triple nostrils in a calf.

BACKGROUND: Nasal abnormalities are rare in bovines. In humans, nasal deformities are mainly classified as proboscis lateralis or supernumerary nostrils. This report discusses the etiology of triple nostrils in a calf, based on computed tomography, magnetic resonance imaging, and endoscopy. CASE PRESENTATION: A female Holstein calf presented with triple nostrils. The following abnormalities were observed: (1) formation of a small and flat blind-ended middle nostril between the right and left nostrils; (2) presence of a hair-bearing surface on the muzzle; (3) abnormal curvature of the nasal septum, resulting in a narrower right nasal cavity due to transformation of the nasal bones; and (4) formation of a bone-like structure within the nasal septum. These findings were similar to those of supernumerary nostrils in humans. CONCLUSIONS: To the best of our knowledge, this represents the first description of a calf with triple nostrils. The use of imaging modalities is necessary for investigating the etiology of triple nostrils.

A Pilot Study on Efficacy of Lipid Bubbles for Theranostics in Dogs with Tumors.

The combined administration of microbubbles and ultrasound (US) is a promising strategy for theranostics, i.e., a combination of therapeutics and diagnostics. Lipid bubbles (LBs), which are experimental theranostic microbubbles, have demonstrated efficacy in vitro and in vivo for both contrast imaging and drug delivery in combination with US irradiation. To evaluate the clinical efficacy of LBs in combination with US in large animals, we performed a series of experiments, including clinical studies in dogs. First, contrast-enhanced ultrasonography using LBs (LB-CEUS) was performed on the livers of six healthy Beagles. The hepatic portal vein and liver tissue were enhanced; no adverse reactions were observed. Second, LB-CEUS was applied clinically to 21 dogs with focal liver lesions. The sensitivity and specificity were 100.0% and 83.3%, respectively. These results suggested that LB-CEUS could be used safely for diagnosis, with high accuracy. Finally, LBs were administered in combination with therapeutic US to three dogs with an anatomically unresectable solid tumor in the perianal and cervical region to determine the enhancement of the chemotherapeutic effect of liposomal doxorubicin; a notable reduction in tumor volume was observed. These findings indicate that LBs have potential for both therapeutic and diagnostic applications in dogs in combination with US irradiation.

Ultrasonography of sudden swollen tongue in a calf.

BACKGROUND: In cattle, the lingual diseases are primarily diagnosed postmortem by histopathological examination of the affected tongues obtained after the death or during necropsy. In humans, ultrasonography has been used to provide differential diagnoses, and for preoperative or intraoperative planning of glossectomy in various lingual diseases. This is a bovine clinical case report, in which ultrasonography for sudden swelling of the tongue, which was possibly caused by snake bite, was utilized as a preoperative indication to perform a glossectomy. CASE PRESENTATION: An eight-month-old female Japanese black calf presented with sudden swelling of the tongue with well-defined discoloration in the cranial region. A 10-MHz linear probe on a portable-type ultrasound machine (MyLabOne VET, Esaote Co., Genova, Italy) was applied to the ventral surface of the tongues in the affected case, and also in five healthy calves under sedation to observe normal tongues. Ultrasonography of the swollen tongue in this case revealed that the ventral lingual muscular layers were severely thickened compared with those of normal tongues. However, the muscle layers were regularly aligned with the echogenic muscular fibers. This resembled the lingual muscular architectures of normal tongues. Color-flow Doppler ultrasonography revealed that blood flow was weakened in the small peripheral vessels in the spaces between the lingual muscular structures, and was lacking in the deep lingual artery between the apex and base of the tongue. This finding was very different than that of normal tongues, which exhibited weakened or rich blood flows. Based on ultrasonographic findings, this case was treated with glossectomy. After recovery, the calf grew up normally with a normal appetite and rumination, and did not exhibit mouth pain behavior. Histopathologically, hemorrhagic necrotic changes, together with focal formation of fibrin thrombus in the lingual blood vessels in the affected tongue, were noted. CONCLUSIONS: To the best of our knowledge, the present report is the first description of lingual ultrasonography performed in cattle. In this case, ultrasonography enabled visualization of decreased vascularity, which might be associated with hemorrhage or formation of fibrin thrombus in the suddenly swollen tongue presented.

Photodynamic detection of a feline meningioma using 5-aminolaevulinic acid hydrochloride.

CASE SUMMARY: The present study describes the case of a feline meningioma that was detected using 5-aminolaevulinic acid hydrochloride (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence at surgery. An extra-axial mass in the temporoparietal region was observed by MRI. Following craniectomy and durotomy, photodynamic detection (PDD) was performed for detection of the tumour. Intratumour PpIX was detected using fluorescence spectrum evaluation and high-performance liquid chromatography. PDD revealed bright fluorescence of PpIX induced by 5-ALA, facilitating fluorescence-guided resection of the tumour tissue. Postoperative examination demonstrated an intratumour PpIX protein concentration of 16.8 nmol/g, and based on histopathological findings we diagnosed the mass as meningioma. RELEVANCE AND NOVEL INFORMATION: PDD using 5-ALA has been used to identify the surgical margins during resection of primary human brain tumours. Recently, we have reported post-mortem PDD using 5-ALA for a canine glioblastoma. To our knowledge, this technique has not been previously used for the detection and resection of feline brain tumours. Our findings suggest that PDD using 5-ALA is useful for intraoperative fluorescence-guided resection of malignant meningioma in cats.

Temporal analysis of histopathology and cytokine expression in the rat cerebral cortex after insulin-induced hypoglycemia.

Hypoglycemic coma causes neuronal death in the cerebral neocortex; however, its unclear pathogenesis prevents the establishment of preventive measures. Inflammation plays a pivotal role in neuronal damage in the hypoglycemic state; however, the dynamics of glial cell activation or cytokine expression remain unknown. Here, we aimed to elucidate the spatiotemporal morphological changes of microglia and time-course cytokine expression profiles in the rat cerebral cortex after hypoglycemic coma. We performed histopathological and immunohistochemical (Iba1, neuronal nuclei, glial fibrillary acidic protein) analyses in the cingulate cortex and four areas of the neocortex: hindlimb area (HL), parietal cortex area 1 (Par1), parietal cortex area 2 (Par2), and perirhinal cortex (PRh). We measured tumor necrosis factor alpha (TNFα) and interleukin-6 messenger RNA (mRNA) expression by real-time reverse transcriptase-polymerase chain reaction. Necrotic neurons appeared in the neocortex as early as 3 h after hypoglycemic coma, while they were absent in the cingulate cortex. Neuronal nuclei-immunopositive neurons in the HL, Par2, and PRh were significantly less abundant than in the control at day 1. In Iba1 immunostaining, large rod-shaped cells were detected at 3-6 h after hypoglycemia, and commonly observed in the HL, Par2, and PRh. After 6 h, rod-shaped cells were rarely observed; instead, there was a prominent infiltration of hypertrophic and ameboid-shaped cells until day 7. The mRNA expression of TNFα was significantly higher than the control at 3-6 h after hypoglycemia in the neocortex, while it was significantly higher only at 3 h in the cingulate cortex. Our results indicate that early and transient appearance of rod-shaped microglia and persisting high TNFα expression levels characterize inflammatory responses to hypoglycemic neuronal damage in the cerebral neocortex, which might contribute to neuronal necrosis in response to transient hypoglycemic coma.

Age-related glomerular lesions with albuminuria in male cotton rats.

The increased prevalence of aging-related chronic kidney disease (CKD) among humans is a problem worldwide. Aged cotton rats (Sigmodon hispidus) are considered novel model animals for studying CKD, especially as the females develop severe tubulointerstitial lesions with anemia. To investigate the renal pathologic features in aged male cotton rats and their characteristic glomerular injuries, the animals were divided into young, adult, old-aged, and advanced-aged groups (1-4, 5-8, 9-12, and 13-17 months, respectively) and pathologically analyzed. Anemia and renal dysfunction, as indicated by hematologic and serologic parameters, were significantly milder in the advanced-aged males than in the old-aged females. The males had increased urinary albumin-to-creatinine ratios from the old-age period, with the advanced-aged males having significantly higher levels than those in the old-aged females and young males. The old-aged females did not show clear glomerular injuries, whereas the advanced-aged males showed membranous lesions characterized by irregular and thickened glomerular basement membranes (GBMs). Characteristically, several large-sized projections from the GBM toward the podocytes were observed by microscopy, and podocytes covering these projections effaced their foot processes. The advanced-aged males showed aging-related IgG immune-complex depositions in the paramesangial regions and along the GBM. Furthermore, the positive reaction for podocin (a podocyte molecule) was granulated along the GBM. Thus, we clarified the albuminuria associated with altered glomerular structures in advanced-aged cotton rats, and that these phenotypes were closely associated with aging. These data help to clarify the aging-related pathogenesis of glomerular injury.

Histopathological and immunohistochemical analysis of the cerebral white matter after transient hypoglycemia in rat.

Patients with hypoglycemic coma show abnormal signals in the white matter on magnetic resonance imaging. However, the precise pathological changes in the white matter caused by hypoglycemic coma remain unclear in humans and experimental animals. This study aimed to reveal the distribution and time course of histopathological and immunohistochemical changes occurring in the white matter during the early stages of hypoglycemic coma in rats. Insulin-induced hypoglycemic coma of 15-30-min duration was induced in rats, followed by recovery using a glucose solution. Rat brains were collected after 6 and 24 hr and after 3, 5, 7, and 14 days. The brains were submitted for histological and immunohistochemical analysis for neurofilament 200 kDa (NF), myelin basic protein, olig-2, Iba-1, and glial fibrillary acidic protein (GFAP). Vacuolation was observed in the fiber bundles of the globus pallidus on days 1-14. Most of the vacuoles were located in GFAP-positive astrocytic processes or the extracellular space and appeared to be edematous. Additionally, myelin pallor and a decrease in NF-positive signals were observed on day 14. Microgliosis and astrogliosis were also detected. Observations similar to the globus pallidus, except for edema, were noted in the internal capsule. In the corpus callosum, a mild decrease in NF-positive signals, microgliosis, and astrogliosis were observed. These results suggest that after transient hypoglycemic coma, edema and/or degeneration occurred in the white matter, especially in the globus pallidus, internal capsule, and corpus callosum in the early stages.

Diagnostic efficacy of imaging and biopsy methods for peritoneal mesothelioma in a calf.

BACKGROUND: Peritoneal mesothelioma is a rare abdominal disease; that occasionally occurs congenitally in younger calves. Cytologic examination of peritoneal effusion (PE) was utilized to diagnose this disease, and was not diagnostic. Diagnostic accuracy has been elevated by recent use of ultrasonography (US), despite most diagnoses have been obtained post-mortem in slaughter houses or during clinical necropsy. In humans, ante-mortem diagnosis is highly associated with clinical use of computed tomography (CT) and laparoscopy together with imaging-assisted biopsy. The present report evaluates the diagnostic applicability of CT and laparoscopy as well as US via the practical application of these imaging modalities in an affected calf, and compares the cytologic and histologic findings among in PE, and specimens obtained from fine-needle aspiration and core-needle biopsy. In addition, the present results were reviewed in comparison with those of previous bovine and human reports. CASE PRESENTATION: A 58-day-old male Japanese black calf presented first with scrotal swelling, followed by progressive abdominal distention. Abnormalities of the case included: 1) accumulation of anechoic PE inside the swollen scrotum and abdomen; 2) formation of multiple echogenic nodules within the peritoneal membrane based on US images; 3) presence of hyper-dense spots (suspected calcification) along the margins of the nodules; 4) anatomic connections between intra-abdominal nodular lesions and the swollen tunica vaginalis via the inguinal region based on CT images; 5) serosanguineous-colored and less-turbid characteristics of PE; and 6) formation of multiple nodules over all of the serosa of the rumen as well as the peritoneal wall based on laparoscopic views. Fine-needle aspiration and core-needle biopsy were successfully performed under US and laparoscopic observations, respectively. Histology findings of the core-needle biopsy specimen appeared more indicative (characterization of tubular structures comprised of cubical or columnar abnormal mesothelial cell linings) diagnostically of peritoneal mesothelioma than did findings of the fine-needle aspiration specimen. CONCLUSIONS: To the best of our knowledge, this report is the first description of clinical applications of CT and laparoscopy to diagnose peritoneal mesothelioma in a calf. Laparoscopy enhanced the diagnostic accuracy due to clear gross visualization of the intra-abdominal abnormalities and applicability to imaging-guided core-needle biopsy.

Imaging and pathological findings of intramedullary inflammatory pseudotumour in a miniature dachshund: a case report.

BACKGROUND: Inflammatory pseudotumours (IPTs) are distinctive lesions consisting of myofibroblastic spindle cells and a variety of inflammatory cells. The aetiology of IPTs is unknown. Reports of IPTs in veterinary medicine have been scarse. Moreover, only one case of intradural extramedullary IPT has been previously reported. In this report, we introduce the first known case of canine IPT, which occurred in the parenchyma of the spinal cord. CASE PRESENTATION: A 10-year-old female Miniature Dachshund presented with a 2-month-long history of progressively worsening ataxia and tetraparesis. Neurological examination was consistent with a lesion involving the cervical spinal cord. Magnetic resonance imaging revealed an intradural space-occupying lesion in the region of the fourth cervical vertebra. Dorsal laminectomy and resection of the mass were performed. Histopathological examination revealed the proliferation of immature spindle cells (fibroblasts/myofibroblasts and glial cells) and a highly cellular mixture of neutrophils, macrophages and lymphocytic cells. The mass was located in the parenchyma of the spinal cord and was diagnosed as an IPT occurring in the parenchyma of the spinal cord. No causative pathogen was detected. The dog's symptoms improved, during the first month after surgery. However, neurological symptoms, such as laboured breathing and dysuria, subsequently worsened and the dog died 42 days after surgery. CONCLUSIONS: The present study describes a canine case of IPT occurring in the parenchyma of the spinal cord. The diagnosis and determination of the site of the mass was difficult solely based on preoperative imaging in the present case. The outcome of this case was poorer than that observed in cases of canine extramedullary IPT and human intramedullary IPT, in which the patients exhibited recovery. The prognosis after surgical resection cannot be decided from the present case alone. However, patients should be monitored for potential serious complications and recurrence.

Slc:Wistar/ST rats develop unilateral thyroid dysgenesis: A novel animal model of thyroid hemiagenesis.

Developmental anomalies of the thyroid gland lead to congenital malformations such as thyroglossal duct cysts and thyroid dysgenesis. However, the pathogenesis of thyroid dysgenesis remains unclear due to the lack of suitable animal models. This study demonstrated that Slc:Wistar/ST rats frequently developed unilateral thyroid dysgenesis, including hemiagenesis, characterized by the absence of one lobe. In Wistar/ST rats, each thyroid lobe was frequently different in size, and approximately 27% and 20% of the rats presented with hemihypoplasia and hemiagenesis of the thyroid gland, respectively. Dysgenesis was predominant on the left side in both sexes, without sex differences. At a young age, thyroid hemiagenesis did not alter body weight. In rats of both sexes with thyroid hemiagenesis, plasma total triiodothyronine and total triiodothyronine levels remained unchanged while plasma thyroid-stimulating hormone levels were significantly elevated in young rats. The remaining thyroid lobes increased in weight, but the follicular epithelial cells appeared normal in terms of their height and proliferating activities. On the side of thyroid dysgenesis, the parathyroid glands were normally localized and were situated at the same location as the contralateral glands. The ultimobranchial body remnants were localized at the level of the thyroid gland along with the cranial thyroid artery and vein, forming cell clusters or cystic structures and containing calcitonin-positive C-cells. In conclusion, Wistar/ST rats developed unilateral thyroid dysgenesis and may be novel and useful animal models for thyroid hemiagenesis in humans and for morphogenesis of pharyngeal pouch-derived organs.