Chronic Inflammatory and Proliferative Lesions of the Gallbladder in Aged Pigs.

Primary epithelial tumors of the gallbladder are rarely reported in animals. In this study, 9 aged pigs (6-12 years old) were histopathologically examined for gallbladder proliferative lesions. At necropsy, a large gallstone occupied the lumen of the gallbladder of 3 pigs. Histopathological examination revealed chronic cholecystitis in all 9 pigs, mucosal hyperplasia in 2 pigs, adenoma in 1 pig, and adenocarcinoma in 2 pigs. Bacilli were detected in the gallbladder lumen of 6 pigs by Warthin-Starry stain. Mucosal hyperplasia, adenoma, and adenocarcinoma were characterized by papillary projections of the mucosa with occasional acinar structures. Tumor invasion of the surrounding tissue was observed in the cases of adenocarcinoma. On Alcian blue and periodic acid-Schiff double-stained sections, the acinar structure of gallbladder mucosa in chronic cholecystitis and mucosal hyperplasia was stained in a mosaic pattern, indicating pyloric gland metaplasia. The results of immunohistochemistry revealed a CD10-positive epithelial brush border and mucin (MUC) 2-positive goblet cells in chronic cholecystitis, adenoma, and adenocarcinomas, indicating intestinal metaplasia. Immunoreactivity of MUC5 AC and cytokeratin 19 was weaker in adenoma and adenocarcinomas compared with the normal and hyperplastic gallbladder mucosa. The number of p53-positive nuclei and the Ki-67 index were higher in adenocarcinomas compared with benign lesions. These results suggest that chronic cholecystitis associated with gallstones and/or bacterial infections may contribute to metaplastic changes and development of gallbladder tumors in aged pigs. Alteration of mucin, cytokeratin, and p53 profiles in gallbladder proliferative lesions in pigs were similar to that in humans, suggesting a common pathogenesis in tumor development.

Fat, Cartilage, and Bone Metaplasia in Lungs of Cattle With Caudal Pleural Lesions and Subjacent Interstitial Fibrosis.

The changes associated with condemned lungs in cattle with chronic pleural lesions of the caudal lobes were characterized by histology and immunohistochemistry (IHC). Fibroproliferative pleural lesions were microscopically confirmed. Occasionally, the pleural lesions also included adipose, chondroid, and osseous metaplasia that were covered by mesothelial cells, mostly in the absence of inflammation. Other lungs also showed fibrosis in the subpleural interstitium and interlobular septa. In both condemned and noncondemned lungs, immunoreactivity to Wilms tumor 1 (WT1) was normally observed on surface mesothelial cells but not on the submesothelial fibroblasts and myofibroblasts. Conversely, the myofibroblasts beneath the pleura, but not the mesothelial cells, showed immunoreactivity to alpha smooth muscle actin and calponin. However, in the lungs with myofibroblastic foci in the pleura, the proliferated cells maintained WT1 immunoreactivity similar to those of some metaplastic cells. These findings may reflect the plasticity of mesothelial cells in vivo.

Assessment of corneal and conjunctival metaplasia by impression cytology during the treatment of canine keratoconjunctivitis sicca.

The purpose of this study was to assess the condition of cells in the conjunctiva and corneal epithelium prior to and during cyclosporine- or tacrolimusbased treatment of keratoconjunctivitis sicca (KCS). The study was performed on 40 dogs with KCS. The dogs were divided into two groups of 20 animals each. In Group I, 0.75% cyclosporine eye drops were administered three times a day, while in Group II 0.02% tacrolimus eye drops were administered twice daily. Additionally, each group was subdivided into three subgroups based on the results of the Schirmer I tear test (STT I). Evaluation of cellular metaplasia in the cornea and the palpebral and bulbar conjunctiva based on the Nelson-Adams scale was performed by impression cytology using Millipore round filters (Millipore VSWP 01300 DA) of 25 µm pore diameter applied to the studied area. Ophthalmological and cytological examinations were performed prior to the treatment as well as after one and two months of therapy. In both groups, a decrease in Nelson-Adams values was observed, corresponding to the increasing STT values [Rxy Spearman statistically significant correlation coefficient values between -0.75 (P < 0.001) and -0.45 (P < 0.01)]. The absence of goblet cells was observed in all dogs, regardless of the KCS stage. Goblet cells reappeared following both tacrolimus- and cyclosporine-based treatment in impression cytology specimens classified as 0 in the Nelson-Adams scale. The extent of corneal and conjunctival metaplasia in the course of tacrolimus- and cyclosporine-based treatment of KCS decreases with increasing STT values.

DISSEMINATED OSSEOUS METAPLASIA OF THE VENTRAL SCALES OF A GRAY-BANDED KINGSNAKE ( LAMPROPELTIS ALTERNA).

A 22-yr-old, female gray-banded kingsnake ( Lampropeltis alterna) was examined for stomatitis and hard ventral scales. On examination, the ventral scales palpated as rigid and brittle. A blood sample yielded marked hypovitaminosis D (11 nmol/L). Radiographs revealed a generalized bone radiopacity outlining the ventral scales; scale biopsies were obtained for histologic examination and presented linear, superficial, and midzonal foci of well-differentiated dermal bone and bone marrow. The stomatitis was successfully treated, but the general condition of the snake declined, and it was euthanized. The most significant finding in the postmortem examination was abnormally pale kidneys. Histologic examination revealed diffuse renal gout and diffuse osseous metaplasia in the dermis of all of the ventral scales. Generalized osseous metaplasia of the ventral scales in snakes has not, to our knowledge, been reported; the cause in this report was not identified, but given the extensiveness of the lesion, it is likely that the cause was multifactorial.

Bilateral laryngeal paralysis in a dog secondary to laryngeal osseous metaplasia.

A 7-year-old spayed female Lurcher was evaluated for a chronic history of increased upper respiratory noise. Advanced imaging including digital radiography and pre- and post-contrast computed tomography (CT) scan confirmed the presence of an ill-defined soft tissue mineralized mass of the ventral larynx. Histopathology demonstrated pleocellular myositis and fasciitis with osseous metaplasia.

Paralysie laryngée bilatérale chez un chien secondaire à la métaplasie osseuse. Une chienne Lurcher stérilisée âgée de 7 ans a été évaluée pour une anamnèse chronique de bruit des voies respiratoires supérieures. Une imagerie avancée, dont une radiographie numérique et une image par tomodensitométrie avant et après contraste a confirmé la présence d'une masse minéralisée floue de tissus mous dans le larynx ventral. Unexamen histopathologique a démontré une myosite pléocellulaire et une fasciite avec une métaplasie osseuse.(Traduit par Isabelle Vallières).

Causes of mortality in anuran amphibians from an ex situ survival assurance colony in Panama.

The success of ex situ survival assurance populations as tools for amphibian conservation depends on the health and reproductive success of founder populations. Necropsy examination and histopathology of animals that die in assurance populations are useful for the identification of population-limiting disease problems and can help to direct applied research efforts in areas such as amphibian husbandry and nutrition. This study reviewed postmortem findings in 167 frogs from 13 species that died in a large Panamanian rescue and survival assurance population between 2006 and 2011. Common problems identified in long-term captive animals, especially in Atelopus species, were epithelial squamous metaplasia suggestive of vitamin A deficiency and a polycystic nephropathy resembling lesions seen in laboratory animals with electrolyte imbalances. Metabolic bone disease was a significant contributor to morbidity in captive-bred juvenile frogs of Gastrotheca cornuta, Hemiphractus fasciatus, and Hylomantis lemur. Findings common to multiple species included poor overall nutritional condition that was sometimes attributable to maladaptation to captive husbandry and epidermal hyperplasia and hyperkeratosis possibly reflecting environmental skin irritation. Infectious diseases and endoparasitism were most common in recently captured animals and included chytridiomycosis and Rhabdias sp. lungworms. Applied research efforts to improve sustainability of survival assurance populations should focus on elucidating optimal husbandry practices for diverse species, improving methods for nutritional supplementation of cultured insects and examination of the role of water composition in disease development.

Benign mixed mammary tumor with sebaceous differentiation in a dog.

We describe here a case of canine mammary benign mixed tumor with sebaceous metaplasia in the right fifth mammary gland of an eight-year-old, intact female Poodle dog. Grossly, the mass was firm with off-white, poorly lobulated cut surfaces. Histologically, the luminal epithelial cells and myoepithelial cells proliferated with cartilage formation and focal squamous metaplasia. Moreover, a large number of nests of various sizes, which were filled with foamy cells in the center and associated with basaloid reserve-like cells in the periphery, showed sebaceous gland-like structures. Immunohistochemically, myoepithelial cells and reserve-like cells in the metaplastic sebaceous gland-like structures were CK14, α-smooth muscle actin (α-SMA) and p63 positive, suggesting a possibility that these two components may have a common cell of origin.

Intrahepatic cholelithiasis with gallbladder-like metaplasia of intrahepatic bile ducts associated with gallbladder agenesis in a wild boar.

An unknown-aged adult female wild boar (Sus scrofa) was brought to Kyungpook National University for postmortem examination. Gross examination revealed gallbladder agenesis. Histologically, the liver was cirrhotic and had intrahepatic cholelithiasis, the choleliths were yellow, brown, gray, and black, and had coffin-lid and pyramidal appearances. Fourier-transform infrared spectroscopy analysis revealed that the components were 80% struvite and 20% calcium oxalate monohydrate. Chronic inflammatory cell infiltration was observed, with hyperplastic hepatocellular nodules characterized by large nuclei, prominent nucleoli, and scant cytoplasm with frequent binucleation, surrounded by thick fibrous septa. The epithelium of intrahepatic bile ducts that contained choleliths had undergone gallbladder-like metaplasia, which might have been induced by chronic irritation from the stones or by the accompanying chronic bacterial infection that was observed in Gram stains.

Lumbar vertebral canal stenosis due to marked bone overgrowth after routine hemilaminectomy in a dog.

BACKGROUND: Bone overgrowth after decompressive surgery for lumbar stenosis resulting in recurrence of neurological signs has not been reported in veterinary literature. However, there are few cases described in human medicine. CASE PRESENTATION: A 13-month-old entire female dog, a crossbreed between a Springer Spaniel and a Border Collie, weighing 24 kg, was referred with a 5-day history of progressive spastic paraplegia, indicative of a T3-L3 myelopathy. Magnetic resonance (MR) imaging revealed a right-sided L2-L3 compressive extradural lesion, compatible with epidural haemorrhage, which was confirmed by histopathology. The lesion was approached via right-sided L2-L3 hemilaminectomy and was successfully removed. One-year postoperatively the dog re-presented with pelvic limb ataxia. MR and computed tomography (CT) images demonstrated excessive vertebral bone formation affecting the right articular processes, ventral aspect of the spinous process of L2-L3, and contiguous vertebral laminae, causing spinal cord compression. Revision surgery was performed, and histopathology revealed normal or reactive osseous tissue with a possible chondroid metaplasia and endochondral ossification, failing to identify a definitive reason for the bone overgrowth. Nine-month postoperatively, imaging studies showed a similar vertebral overgrowth, resulting in minimal spinal cord compression. The patient remained stable with mild proprioceptive ataxia up until the last follow-up 18 months post-revision surgery. CONCLUSION: This is the first report in the veterinary literature of bone overgrowth after lumbar hemilaminectomy which resulted in neurological deficits and required a revision decompressive surgery.

Metastatic intestinal adenocarcinoma with osseous metaplasia in two Domestic Korean Shorthair cats.

Two Domestic Korean Shorthair cats presented with dyschezia and vomiting. Computed tomography revealed a colonic mass with calcification and lymph node metastasis in case 1, and a small intestinal mass with disseminated mesenteric metastasis and calcification in case 2. Histopathology revealed intestinal adenocarcinoma with osseous metaplasia. Case 1 died two months after surgery from distant metastasis; and case 2 showed no metastasis for five months but presented with anorexia, euthanized seven months after diagnosis. Metastatic intestinal adenocarcinoma with bone formation should be considered as differential diagnosis for calcification on imaging, and lymph node metastasis at diagnosis may indicate poor prognosis.

Streptococcus canis prostatitis and endocarditis with thromboembolism in a dog with sertoli cell tumour in a cryptic testis and prostatic squamous metaplasia.

We describe an unusual case of prostatitis caused by Streptococcus canis evolving to endocarditis and splenic, renal, and cerebral thromboembolism in a dog, associated with a Sertoli cell tumour in a cryptic testis and diffuse prostatic squamous metaplasia. A nine-year-old, intact male, mixed-breed dog was presented to a veterinary teaching hospital with abdominal pain and prostration. Physical examination and abdominal ultrasonography revealed an atrophic right testicle located in the subcutaneous tissue. The left testicle was in the abdominal cavity with increased dimensions and irregular contours. Complete blood count analysis showed marked neutrophilic leukocytosis and thrombocytopenia. After clinical worsening, euthanasia was performed, and the dog was submitted to post-mortem examination. The main gross findings included testicular malposition with one cryptic and one ectopic testis, enlarged prostate with purulent content, distension of the urinary bladder with cloudy urine, vegetative valvular endocarditis in the mitral valve, and spleen and renal infarcts. Histological examination showed a Sertoli cell tumour in the abdominal testis, diffuse prostatic squamous metaplasia with marked keratinization associated with bacterial prostatitis, fibrinonecrotic cystitis, bacterial endocarditis with marked myxomatous degeneration in the mitral valve, and splenic, renal, and cerebral thromboembolism. Microbiological analysis identified Streptococcus canis in the prostate and mitral valve. Sertoli cell tumour of cryptic testis increases oestrogen production and leads to squamous metaplasia of the prostate, which should be considered as predisposing factors for ascending S. canis infection from the urogenital tract to the prostate. Then, haematogenous spread of S. canis from the prostate to mitral valve cause endocarditis and subsequent thromboembolism and infarcts, all decisive to poor prognosis in this case.

Metaplastic Ossification of a Giant Paraprostatic Cyst in a Dog: A Case Report.

A 7-year-old male Caucasian shepherd presented with a 3 month history of intermittent hematuria, penile discharge, and abdominal pain and distension. The dog had a history of prostatic hyperplasia with multiple cysts, diagnosed by the referring clinician two years prior to the case presentation. Two oral courses of antibiotics and antiandrogens were administered by the treating veterinarian without resolution. At the case presentation visit, massive swelling was present in the mid- and caudal parts of the abdomen. Abdominal ultrasound and exploratory laparotomy revealed a paraprostatic cyst (size: 25 × 20 × 18 cm) in the caudal part of the abdomen. The cyst had a bony ridge along the wall with multiple cauliflower-like lesions extending inside. Histopathologic examination revealed an intermittently epithelial-lined inner wall of the cyst, which was partially degenerated and flattened due to the pressure of the intraluminal fluid. The luminal surface of the cyst appeared markedly irregular with multiple structures made of dense, fibrous connective tissue protruding inside with metaplastic ossification foci, consistent with severe osseous metaplasia. The epithelium showed focal secretory activity. Numerous subepithelial multifocal neutrophil and mononuclear cellular infiltrates were found. The lumen of the cyst contained a reddish-brown (blood and protein-rich) fluid. Complete surgical excision of the cyst and omentalization of the capsular remnant resulted in successful resolution of the clinical signs.

Cartilaginous metaplasia in the sclera of Suffolk sheep.

Scleral cartilaginous metaplasia was detected by routine histologic examination of globes from 5 Suffolk sheep from a scrapie pathogenesis study. The extent of the metaplasia varied among the sheep but was always posterior to the tapetal fundus. The matrix surrounding chondrocytes stained intensely with alcian blue and was immunopositive for type II collagen. Retrospective evaluation of additional eyes from Suffolk and Cheviot sheep used in various scrapie pathogenesis studies at the authors' facility revealed similar histologic changes in 40% and 12.7% of eyes examined, respectively. The clinical significance of this previously unreported finding is unknown.

Ectopic Splenic Adenocarcinoma in a Dog.

A 10-year-old spayed female Border Collie developed a ductal adenocarcinoma in the spleen. Clinically, the spleen was enlarged and a small liver nodule was present but there were no other abnormalities. Most of the splenic parenchyma was diffusely infiltrated by variably shaped atypical neoplastic cells that formed small clusters or larger nests, arranged as duct or duct-like structures within a fibrous matrix. There was acinar differentiation in a few portions of the tumour with a sheet-like solid growth pattern and occasional squamous metaplasia or exocrine acinus-like structures. Mitotic figures were frequent. Neoplastic cells with ductal differentiation were diffusely immunoreactive for AE1/AE3, CAM5.2 and CK7 cytokeratins but negative for CK20, while cells with acinar differentiation were immunolabelled only for AE1/AE3 cytokeratins and were also immunopositive for mucin-1 and trypsin. A few regions of tumour with ductal or acinar differentiation were immunopositive for pancreatic lipase. All neoplastic cells were negative for mucin-2, vimentin, smooth muscle actin, chromogranin A, CD31, hepatocyte paraffin 1 and thyroglobulin antigens. Because of the formation of exocrine acinus-like structures and an immunolabelling pattern consistent with exocrine pancreas tissue, an adenocarcinoma of ectopic exocrine pancreas within the spleen was diagnosed.

Adenomatous polyp with intestinal metaplasia of the esophagus (Barrett esophagus) in a dog.

Multiple endoscopic biopsy specimens of esophageal mucosa were received from a 13-year-old castrated male standard Poodle. The dog was presented for painful swallowing. Endoscopically, the distal aspect of the esophagus was inflamed with a polypoid mass that protruded into the esophageal lumen. Histologically, the stratified squamous epithelium overlying the mass and lining the adjacent esophageal mucosa was replaced by papillary projections covered by columnar epithelium with goblet cells supported by a fibrous stroma. This article reports a case of spontaneous esophageal adenomatous polyp with intestinal metaplasia (Barrett esophagus) and reviews the pathogenesis of esophageal metaplasia and adenocarcinoma.

Fibroma with osseous metaplasia of external auditory canal in a dog.

The present report describes a case of fibroma with osseous metaplasia of the external auditory canal in a 7-year-old male Pomeranian dog. Upon otoscopic examination, the right external auditory canal was almost completely obstructed by a well-circumscribed mass adjacent to the eardrum. The mass was surgically excised. Grossly, it was well demarcated, firm when cut, pink, and measured 0.3 cm x 0.2 cm x 0.7 cm. The cut surface of the mass exhibited a central portion of homogeneously white osseous components surrounded by brown to pink soft tissue. Microscopically, the resected external auditory canal mass mainly consisted of fibroblastic spindle cells showing differentiation to metaplastic osteoblast-like cells. Metaplastic osteoblasts and osteoclasts lining the osteoid bony trabeculae were also observed. Bony trabeculae and spicules were separated by abundant collagen and neoplastic fibroblastic cells. Fibromatous components, irregular formation of woven bone spicules, and the presence of osteoblasts lining bony trabeculae led to a diagnosis of fibroma with osseous metaplasia.

An aortic body carcinoma with sarcomatoid morphology and chondroid metaplasia in a French Bulldog.

An 11-year-old female French Bulldog was presented with a mass at the base of the heart, detected by X-ray and echocardiography. Clinical abnormality included abdominal retention by ascites. Radiation therapy was performed for 5 weeks. The mass volume didn't change during the radiotherapy. The condition became worse and the dog died 6 months after the initial presentation and necropsy was performed. Grossly, the mass, 12.5 × 6.5 × 6.0 cm in size, was found at the base of the heart. Histopathological examination revealed that cardiac mass was composed of alveolar, bundle and diffuse proliferation of neoplastic cells. Most of the neoplastic cells showed a spindle morphology; in some areas small round or polyhedral neoplastic cells were observed. Occasional cartilage metaplasia was seen multifocal in the mass, and it was surrounded by the sarcomatoid proliferation. Electron microscopy revealed a few neuroendocrine granules in the cytoplasm of spindle and polyhedral neoplastic cells. Metastatic cells in the lungs which had not irradiated demonstrated typical morphology of aortic body tumors. Based on these findings, the case was diagnosed as an aortic body carcinoma with sarcomatoid morphology and chondroid metaplasia.

Salivary mucocele with osseous metaplasia in a dog.

A 4-year-old, male, dachshund was referred to a certain local veterinary hospital because of a soft and fluctuant swelling in the left upper cervical region. The swelling was surgically removed and appeared to be filled with bloody mucus. Grossly, the swelling was identified as salivary mucocele and showed small multifocal whitish ossified tissue on its surface. Microscopically, the wall of salivary mucocele appeared as granulation tissue surrounding mucin, which was composed of loose edematous and vascularized connective tissue containing chronic inflammatory cells such as lymphocytes, plasma cells and macrophages. Characteristically, present case had ossifying components formed by metaplastic spindle cells in the wall of salivary mucocele. Therefore, the present case was diagnosed as salivary mucocele with osseous metaplasia in a dog.

Tubulopapillary carcinoma with spindle cell metaplasia of the mammary gland in a cat.

Sarcomatous proliferation of spindle cells was present in the mammary gland and many metastatic sites in a 10-year-old female domestic cat with tubulopapillary carcinoma in the mammary gland. Transition from neoplastic tubular structures to spindle cells in the primary site and fascicular proliferation of the spindle cells with or without coexistance of tubulopapillary carcinoma in the primary and metastatic sites were observed. Most of spindle cells were positive for cytokeratin CAM5.2 as well as the normal luminal epithelium but not the myoepithelium. From these results, this case was diagnosed as tubulopapillary carcinoma with spindle cell metaplasia and it was clarified that neoplastic luminal epithelial cells can transform to sarcomatous appearence.

Canine breeds associated with gastric carcinoma, metaplasia and dysplasia diagnosed by histopathology of endoscopic biopsy samples.

BACKGROUND: Gastric carcinoma (GC) is a rather rare pathological finding in dogs, with the exception of some breeds which seem predisposed. The etiopathogenesis is largely unknown in dogs, whereas in humans GC often develops from gastric mucosal metaplasia and dysplasia. This study investigates whether dogs of certain breeds are more often subject to gastroduodenoscopy (GDS), and diagnosed with GC, mucosal metaplasia or dysplasia. A retrospective clinical database search was performed at the Veterinary Teaching Hospital at the University of Helsinki, Finland. The following inclusion criteria were applied to estimate relative risk for metaplasia/dysplasia and GC: dogs from pure breeds with at least five individuals subject to GDS with histopathology of gastric biopsies. RESULTS: Between 2006 and 2016, from a total of 54945 canine patients presented, 423 dogs underwent GDS. Inclusion criteria were met in 180 dogs of 20 different pure breeds. Eight dogs had GCs (mean age = 9.8 ± 1.7 years): Belgian Tervuren (n = 4), Collie (n = 2), Golden Retriever (n = 1) and Jack Russel Terrier (n = 1). Fourteen dogs of eight breeds had gastric mucosal metaplasia or dysplasia. A log-binomial statistical model revealed that dogs in the following breeds had a significantly higher probability to undergo GDS than the others in the study population: Australian Terrier, Belgian Tervuren, Cairn Terrier, Collie and Siberian Husky. Belgian Tervuren was found at higher risk to be diagnosed with GC [RR = 19 (5.7-63.9; P < 0.0001)], as well as mucosal metaplasia/dysplasia [RR (7.6; 2.95-19.58; P < 0.0001)], as compared to the other breeds included. Shetland Sheepdog had an increased RR (5.83; 1.75-19.45; P = 0.0041) for metaplasia. CONCLUSIONS: The results indicate a very low incidence of GC in dogs. The Belgian Tervuren, however, appears as predisposed. The histopathologic descriptions of mucosal changes such as metaplasia and dysplasia were also rare, but were more frequent in the Belgian Tervuren. Previous reports of these changes in dogs are very scarce, but they might be presumably related to GC in dogs, as they are in humans. Future research should investigate the possible role of metaplasia and dysplasia in the development of GC in dogs, especially those of predisposed breeds.