Establishment of Primary Cell Cultures from Canine Oral Melanomas via Fine-Needle Aspiration: A Novel Tool for Tumorigenesis and Cancer Progression Studies.

Oral melanomas are the most common oral malignancies in dogs and are characterized by an aggressive nature, invasiveness, and poor prognosis. With biological and genetic similarities to human oral melanomas, they serve as a valuable spontaneous comparative model. Primary cell cultures are widely used in human medicine and, more recently, in veterinary medicine to study tumorigenesis, cancer progression, and innovative therapeutic approaches. This study aims to establish two- and three-dimensional primary cell lines from oral canine melanomas using fine-needle aspiration as a minimally invasive sampling method. For this study, samples were collected from six dogs, represented by four primary oral melanomas and five lymph nodal metastases. The cells were digested to obtain single-cell suspensions, seeded in flasks, or processed with Matrigel® to form organoids. The cell cultures were characterized through flow cytometry using antibodies against Melan-A, PNL2, and Sox-10. This technique offers a minimally invasive means to obtain cell samples, particularly beneficial for patients that are ineligible for surgical procedures, and enables the establishment of in vitro models crucial for comparative studies in mucosal melanoma oncology. To the best of our knowledge, this is the first work establishing neoplastic primary cell cultures via fine-needle aspiration in dogs.

Comparison of Butorphanol, Methadone, and Pethidine in Combination with Alfaxalone for Premedication in Isoflurane-Anesthetized Cats Undergoing Ovariectomy.

The aim of this study was to compare three different anesthetic protocols administered intramuscularly (IM) in cats undergoing elective ovariectomy, while evaluating the quality of sedation, antinociceptive, isoflurane-sparing effect, and analgesia in the intra-operative and post-operative phases. A total of 71 female cats were sedated IM with alfaxalone (3 mg/kg) combined with either butorphanol (0.3 mg/kg), methadone (0.3 mg/kg), or pethidine (5 mg/kg). During surgery, vital parameters were constantly monitored; at the end of the procedure, the quality of recovery was assessed through a specific form and each cat was scored for perceived pain using the UNESP-Botucatu scale for 5 days, and rescue analgesia was provided with buprenorphine IM when indicated. Moreover, differences between two different post-operative resting regimens (hospital kennels vs. home) were also assessed. A significant difference emerged for the amount of IM dexmedetomidine required to achieve an adequate level of sedation for intravenous catheterization, highlighting a greater need in the pethidine group (p = 0.021). There was no significant difference between opioid groups for the requirement of intra-operative rescue analgesia, and the clinical parameters were kept within physiological ranges regardless of the opioid used in premedication. Lastly, differences between the UNESP-Botucatu scores were detected from day 3 to day 5 post-operatively, with lower scores in cats with home resting regimens compared to the hospitalized animals, likely due to the presence of an unfamiliar condition and the absence of a cat-friendly environment.

Risk of peripheral neuropathy in patients with psoriasis and psoriatic arthritis. A prospective cohort study.

INTRODUCTION/AIMS: Laboratory and clinical data suggest a link between neurologically mediated inflammation and psoriasis, but the risk and features of peripheral neuropathy in psoriasis or psoriatic arthritis remain unknown. The aim of this exploratory study was to evaluate the risk and to describe the features of peripheral neuropathy in patients with psoriasis and psoriatic arthritis. METHODS: One hundred patients with psoriasis and/or psoriatic arthritis and 100 control subjects were consecutively enrolled. Diagnostic confirmation included electrophysiological examination, skin biopsy, and nerve ultrasound for confirmed polyneuropathy. RESULTS: Nine patients were diagnosed with confirmed polyneuropathy, while none of the control subjects had the condition (relative risk [RR] = 19.00, 95% confidence interval [CI] = 1.12-322.11). Specific relative risks for polyneuropathy were 22.09 (95% CI = 1.17-416.43) in psoriasis patients and 18.75 (95% CI = 1.07-327.62) in psoriatic arthritis patients. The observed polyneuropathy in all nine patients was length-dependent, symmetrical, and predominantly sensory, with minimal or no disability. Comorbidities and exposure to therapies known to increase the risk of polyneuropathy were more frequent in psoriasis and/or psoriatic arthritis patients compared to controls (42% vs. 4%, p = .0001). Analyzing data after excluding possible contributory causes, the risk of polyneuropathy in patients with psoriasis and/or psoriatic arthritis was not significant. DISCUSSION: Psoriasis and psoriatic arthritis appear to be associated with an increased risk of polyneuropathy. This increased risk seems to be linked to the higher prevalence of contributing factors for polyneuropathy, rather than a direct increase in neuropathy risk specifically related to psoriasis and psoriatic arthritis.

Recidivism risk in male adult sex offenders with psychopathic traits assessed by PCL-R: A systematic review.

Psychopathy has been empirically associated with various forms of antisocial behavior including sexual assault. In fact, the lack of empathy characterizing psychopathic offenders may facilitate the perpetration of more extreme violence. This systematic review aims to explore the relationship between psychopathy traits in male adult sex offenders and the increase in recidivism risk for any type of reoffence, with a special focus on sexual recidivism. From an initial sample of 757 articles related to the topic, only 14 were selected from the current literature at the end of the inclusion process. Each of these assessed the relation between psychopathy traits (measured by PCL-R) and recidivism risk in male sex offenders (age > 18), providing an effect size (quantitative findings). The results of their analysis agree with the currently available literature: the presence of psychopathic traits in sex offenders would seem to correlate with an increased risk of recidivism of general but non-sexual. Furthermore, almost half of the included works highlighted a positive relationship between psychopathy and violent reoffences. However, the limited availability of studies and the unevenness in their results indicate the need to expand future research in this direction.

The impact of farming on prehistoric culinary practices throughout Northern Europe.

To investigate changes in culinary practices associated with the arrival of farming, we analysed the organic residues of over 1,000 pottery vessels from hunter-gatherer-fisher and early agricultural sites across Northern Europe from the Lower Rhine Basin to the Northeastern Baltic. Here, pottery was widely used by hunter-gatherer-fishers prior to the introduction of domesticated animals and plants. Overall, there was surprising continuity in the way that hunter-gatherer-fishers and farmers used pottery. Both aquatic products and wild plants remained prevalent, a pattern repeated consistently across the study area. We argue that the rapid adaptation of farming communities to exploit coastal and lagoonal resources facilitated their northerly expansion, and in some cases, hunting, gathering, and fishing became the most dominant subsistence strategy. Nevertheless, dairy products frequently appear in pottery associated with the earliest farming groups often mixed with wild plants and fish. Interestingly, we also find compelling evidence of dairy products in hunter-gatherer-fisher Ertebølle pottery, which predates the arrival of domesticated animals. We propose that Ertebølle hunter-gatherer-fishers frequently acquired dairy products through exchange with adjacent farming communities prior to the transition. The continuity observed in pottery use across the transition to farming contrasts with the analysis of human remains which shows substantial demographic change through ancient DNA and, in some cases, a reduction in marine consumption through stable isotope analysis. We postulate that farmers acquired the knowledge and skills they needed to succeed from local hunter-gatherer-fishers but without substantial admixture.

Application of Ultrasound in Detecting and Removing Migrating Grass Awns in Dogs and Cats: A Systematic Review.

Migrating grass awns are an important cause of disease in dogs and cats. Plant awns can migrate into several body tissues and cavities because of their fusiform shape and backward-pointing barbs. Their migration causes inflammatory tissue reaction and clinical signs depend upon their localization. Ultrasound has been described as a useful, noninvasive, and readily available tool to identify and guide vegetal foreign bodies removal in animals. The aim of this systematic review was to summarize current knowledge on the application of ultrasonography in the identification and removal of grass awns from various anatomic locations in dogs and cats. We selected and analyzed 46 papers on the application of ultrasonography in dogs and cats affected by migrating grass awns. The ultrasonographic appearance of grass awns is characteristic, although their size and location can influence the visualization and the attempt of removal. In some cases, migrating grass awns are not directly visualized by ultrasonography, but the lesions caused by their migration can be easily seen. Ultrasonography can be considered a useful diagnostic tool to localize and remove migrating grass awns; however, when the migration occurs in less accessible locations or discrete foreign bodies are present, this diagnostic tool should be considered as a part of a multidisciplinary approach with advanced diagnostic imaging modalities.

Mind the past: A systematic review on psychological autopsy.

Psychological Autopsy (PA) has become widespread to the point of being applied in many diverse fields. However, it is difficult to identify a standard model. In this systematic review, we focused on PA studies assessing mental illness as a major risk factor for suicide. The research, performed on Scopus, Embase, and Pubmed to cover the last 20 years led to 321 reports of which 15 met the inclusion criteria. Results confirmed mental illness as the main risk factor for suicide, followed by specific socio-demographic factors and life events. The analysis of methodologies depicted a still highly heterogeneous scenario, especially regarding data collection and variables included. However, concerning psychiatric evaluations, an initial standardization process of PA models emerged. In conclusion, the approach is in evolution, and novel guidelines are needed to promote the application of PA as a fundamental tool to inform suicide prevention efforts and to assist forensic examiners in court.

Intracardiac Porcupine Quill Migration in a Dog: Multimodality Imaging Findings and Surgical Management.

The porcupine is a nocturnal quill-bearing rodent common throughout Italy. When threatened, it defends itself by erecting its quills, rattling its tail, and running sideways or backyard into predators. The quills are released upon contact with assailants and tend to migrate into several body tissues or cavities due to the unique inverted cuticles (crenate) directed downwards to the quill base (a sort of "harpoon effect"). Intracardiac migration of porcupine quills has been reported in a few dogs with severe clinical signs. This case report describes a single porcupine quill [Hystrix cristata, (HC)] migration through the heart in a dog and the use of multimodality imaging for the diagnosis and surgical approach. A 4-year-old 25 kg female mixed-breed dog was presented for evaluation of recurrent fever. Transthoracic echocardiographic examination showed a linear, hyperechoic foreign body traversing the interventricular septum from the heart base to the cardiac apex. Computed tomography and transesophageal echocardiography confirmed the presence of a single structure resembling a quill; a later esophageal endoscopy showed no anatomical alterations or mucosal injuries. Following median sternotomy and after accurate localization by intraoperative ultrasound, the quill was successfully removed. The dog had a good recovery without evidence of severe cardiac injury secondary to an intracardiac quill. To the best of the authors' knowledge, the identification of an intracardiac HC quill by ultrasonography and CT and its successful removal by ultrasound guide has not been previously reported.

Palliative repeated electroporations of oral tumours in dogs: A case series.

Electrochemotherapy (ECT) is a highly developed treatment for many solid tumours that provides good local control in 80% of neoplasms in dogs. ECT can be used to treat different types of tumours, particularly as an innovative approach for non-resectable masses. As reported in the literature, electroporation-based treatments are safe, simple, fast and cost-effective treatment alternatives for selected oral and maxillofacial tumours not involving the bone in dogs (e.g., small squamous cell carcinoma or malignant melanoma). In this descriptive retrospective paper, the authors describe the outcome of various types of oral tumours treated with ECT as a palliative first line treatment or as a rescue treatment in dogs with local tumour recurrence. Nineteen dogs were included and treated with at least one session of three electroporations coupled with intravenous administration of bleomycin every 21 days. Tumour size, localization, histotype, stage, recurrence, solid tumour response evaluation criteria (RECIST), local toxicity, progression free survival (PFS) and median survival time (MST) were evaluated. The small population did not allow the analysis of the ECT response by comparing different tumour types; further studies with a larger caseload are needed. However, all dogs, despite the low MST, showed a good local response to treatment with a rapid improvement in quality of life from the first ECT application; no side effects attributable to chemotherapy have been detected and toxicity due to the electroporation was minimal and well tolerated in all dogs.

Sedation quality of alfaxalone associated with butorphanol, methadone or pethidine in cats injected into the supraspinatus or the quadriceps muscle.

OBJECTIVES: The aim of this study was to compare the quality of sedation with three different anaesthetic protocols (alfaxalone combined with butorphanol, methadone or pethidine) administered intramuscularly in cats, and to evaluate the influence of the injection site (between supraspinatus and quadriceps muscles) on the onset and quality of sedation. METHODS: A total of 151 cats were selected for this study. Cats were sedated with alfaxalone (3 mg/kg) combined with either butorphanol (0.3 mg/kg; n = 50), methadone (0.3 mg/kg; n = 53) or pethidine (5 mg/kg; n = 48). The combination was injected intramuscularly into the supraspinatus (n = 79) or quadriceps muscle (n = 72). The data included a scoring system for the quality of sedation and physiological parameters, such as heart rate (HR), respiratory rate, body temperature and occurrence of mydriasis, monitored during the first 30 mins of anaesthesia. RESULTS: The opioid associated with alfaxalone influenced the overall sedation score, the degree of myorelaxation, the occurrence of mydriasis and HR. The overall sedation score was poorer with butorphanol than with methadone (P = 0.008), and butorphanol induced a lower degree of myorelaxation than methadone (P = 0.013). The injection into the supraspinatus showed better qualitative results for sedation and a faster onset time (in about 3 mins) than that into the quadriceps (P <0.001). HR decreased from baseline (P <0.001) and over time (P <0.001), mainly in cats of the butorphanol-supraspinatus and pethidine-quadriceps groups (P = 0.004). The occurrence of mydriasis was lower after butorphanol than after methadone and pethidine (P = 0.025), while the incidence of side effects did not differ among groups. CONCLUSIONS AND RELEVANCE: All three protocols provided a good quality of sedation and allowed performing the scheduled procedure. Moreover, the injection into the supraspinatus muscle showed superior results in all the qualitative scores of sedation and quicker onset time than that into the quadriceps muscle.

Methadone or Butorphanol as Pre-Anaesthetic Agents Combined with Romifidine in Horses Undergoing Elective Surgery: Qualitative Assessment of Sedation and Induction.

While butorphanol is the most commonly used opioid in horses, methadone is not licensed in most countries. Our aim was to compare the effects of both drugs, combined with romifidine, regarding the quality of sedation and induction in horses undergoing elective surgery. Results indicate the suitability of both methadone and butorphanol in this patient population. Animals were scored 10 min after intravenous injection of sedatives. Despite lower overall sedation (OS) score in horses receiving methadone (p = 0.002), the quality and time of induction and intubation remained unchanged. None of the horses had the lowest OS score (no sedation), nor the highest score for ataxia (horse falling). Methadone induced a tendency for minor noise reaction yet minor head lowering scores, the latter being probably the most influencing parameter when scoring OS. Measured physiological parameters decreased in both groups, with greater bradycardia recorded after methadone (p = 0.017), including a higher incidence of atrioventricular blocks that resolved during general anaesthesia. The quality of induction was good-excellent in most of the animals. While comparisons between the degree of antinociception were beyond the scope of this study, analgesic potency might influence the choice when considering opioids as pre-anaesthetic drugs in combination with romifidine before surgery in equines.

Characterization of Primary Cultures of Normal and Neoplastic Canine Melanocytes.

Although numerous animal models, especially mouse models, have been established for the study of melanoma, they often fail to accurately describe the mechanisms of human disease because of their anatomic, physiological, and immune differences. The dog, as a spontaneous model of melanoma, is nowadays considered one of the most valid alternatives due to the heterogeneity of clinical presentations and of histological and genetic similarities of canine melanoma with the human counterpart. The aim of the study was to optimize a protocol for the isolation and cultivation of healthy and neoplastic canine melanocytes derived from the same animal and obtained from cutaneous and mucosal (oral) sites. We obtained five primary tumor cell cultures (from 2 cutaneous melanoma, 2 mucosal melanoma and 1 lymph node metastasis) and primary normal melanocyte cell cultures (from normal skin and mucosa) from the same dogs. Immunocytochemical characterization with Melan A, PNL2 and S100 antibodies confirmed the melanocytic origin of the cells. This work contributes to expanding the case record of studies on canine melanoma cell cultures as suitable model to study human and canine melanoma. To the authors' knowledge, this is the first report of isolation of normal skin and mucosal canine melanocytes.

Looking for Minor Phenolic Compounds in Extra Virgin Olive Oils Using Neutron and Raman Spectroscopies.

Extra virgin olive oil (EVOO) is defined as a functional food as it contains numerous phenolic components with well-recognized health-beneficial properties, such as high antioxidant and anti-inflammatory capacity. These characteristics depend on their structural/conformational behavior, which is largely determined by intra- and intermolecular H-bond interactions. While the vibrational dynamics of isolated compounds have been studied in a number of recent investigations, their signal in a real-life sample of EVOO is overwhelmed by the major constituent acids. Here, we provide a full characterization of the vibrational spectroscopic signal from commercially available EVOO samples using Inelastic Neutron Scattering (INS) and Raman spectroscopies. The spectra are dominated by CH2 vibrations, especially at about 750 cm-1 and 1300 cm-1. By comparison with the spectra from hydroxytyrosol and other minor phenolic compounds, we show that the best regions in which to look for the structure-activity information related to the minor polar compounds is at 675 and 1200 cm-1 for hydroxytyrosol, and around 450 cm-1 for all minor polar compounds used as reference, especially if a selectively deuterated sample is available. The regional origin of the EVOO samples investigated appears to be related to the different amount of phenolic esters versus acids as reflected by the relative intensities of the peaks at 1655 and 1747 cm-1.

Prostatic Localization of a Migrating Grass Awn Foreign Body in a Dog.

A 13-year-old male mixed-breed dog was examined because of hematuria and pyrexia. Ultrasonographic examination of the genitourinary tract showed the presence of a migrating grass awn in the right prostatic lobe. Laparotomy allowed, under ultrasonographic guidance, to remove entirely the migrating grass awn from the prostatic parenchyma. The recovery was uneventful and four months after the surgery the owner reported that the dog showed the complete resolution of the clinical signs and full return to normal activity. To our knowledge, this case report describes for the first time the clinical presentation, imaging findings, management and outcome for a dog with prostatic localization of a migrating grass awn.

Seasonal Expression of NGF and Its Cognate Receptors in the Ovaries of Grey Squirrels (Sciurus carolinensis).

The grey squirrel is an invasive alien species that seriously threatens the conservation of the native red squirrel species. With the aim of characterizing the reproductive physiology of this species due to its great reproductive success, the function of the ovarian nerve growth factor (NGF) system was analyzed in a grey squirrel population living in central Italy. During the breeding and nonbreeding seasons, the ovarian presence, distribution, and gene expression of NGF, neurotrophic tyrosine kinase receptor 1 (NTRK1), and nerve growth factor receptor (NGFR), as well as NGF plasma concentrations, were evaluated in female grey squirrels. NGF was found in the luteal cells and in the thecal and granulosa cells of follicles, while NTRK1 and NGFR were only observed in follicular thecal and granulosa cells. NGF and NGFR transcripts were almost two-fold greater during the breeding season, while no seasonal differences were observed in NTRK1 gene expression. During the breeding season, NGFR was more expressed than NTRK1. Moreover, no changes were observed in NGF plasma levels during the reproductive cycle. The NGF system seems to be involved in regulating the ovarian cycle mainly via local modulation of NGF/NGFR, thus playing a role in the reproductive physiology of this grey squirrel population.

A Comparative Study of Intramuscular Alfaxalone- or Ketamine-Based Anesthetic Mixtures in Gray Squirrels Undergoing Gonadectomy: Clinical and Physiologic Findings.

The gray squirrel is one of the most common invasive species in Europe, whose presence is dangerous for the survival of the European red squirrel. To cope with this biological invasion and to safeguard biodiversity, the LIFE+U-SAVEREDS project aims to protect the red squirrel, by limiting the growth of the current population of gray squirrels and simultaneously promoting their eradication with surgical sterilization. This study compares two different anesthetic protocols, including dexmedetomidine (40 µg/kg) and midazolam (0.3 mg/kg) associated with ketamine (15 mg/kg; n = 25 squirrels) or alfaxalone (5 mg/kg; n = 22 squirrels). A blinded investigator evaluated the quality and onset of sedation, intraoperative anesthesia, and recovery, as well as the physiologic parameters for each animal. Alfaxalone provided a good quality of anesthesia with limited cardiovascular effects (p < 0.05) and good intraoperative myorelaxation. Ketamine induced complete relaxation in a shorter time (p < 0.05) and a rapid (p < 0.001) and excellent (p < 0.05) recovery. Despite the overall superiority of ketamine, alfaxalone appeared to be an adequate alternative anesthetic drug that can be administered without requiring intravascular access. It should be rapidly metabolized and excreted; however, it requires the combination of longer acting sedatives/myorelaxants to prevent a poor recovery quality.

Severe Pleural Effusion in a Dog Affected by Larval Mesocestodiasis.

A 4-year-old, 20 kg, female mixed breed dog was referred to our Veterinary Teaching Hospital for severe respiratory distress. Thoracic ultrasonography revealed severe pleural effusion with multiple anechoic cystic structures within the fluid. Abdominal cavity presented few small and irregular cystic structures. Diagnosis of infection by larval stages of Mesocestoides spp. on the basis of a PCR approach was performed and therapy with oral fenbendazole was started. Due to an incomplete clinical response, the dog underwent to remove metacestodes cysts by surgical debridement. The dog showed no recurrence of clinical signs for 12 months after the surgery. Pleural larval cestodiasis should be added as a differential diagnosis in the list of diseases causing pleural effusion in dogs.

Pharmacokinetics and analgesic efficacy of intranasal administration of tramadol in dogs after ovariohysterectomy.

OBJECTIVE: To assess analgesic efficacy and the pharmacokinetics of intranasal (IN) tramadol in dogs following ovariohysterectomy. STUDY DESIGN: Randomized, blinded clinical study. ANIMALS: A total of 30 bitches undergoing elective ovariohysterectomy. METHODS: Dogs were randomly assigned to one of three experimental groups (10 dogs per group): IN tramadol 4 mg kg-1 (group T-IN), intravenous (IV) tramadol 4 mg kg-1 (group T-IV) and IV methadone 0.2 mg kg-1 (group M). Drugs were administered at extubation. At established time points (before surgery and up to 8 hours after drug administration) analgesia was assessed using the Italian version of the Glasgow Composite Measure Pain Scale Short Form and physiological variables were recorded. To determine the pharmacokinetics of IN tramadol, blood samples were collected at predetermined time points. Shapiro-Wilk test was used to assess whether data were normally distributed and consequently parametric or non parametric tests were applied. A p value < 0.05 was considered significant. RESULTS: No significant intergroup differences were observed in the dogs that were administered rescue analgesia and time of its administration. Excluding dogs that were administered rescue analgesia, no significant intergroup differences emerged in pain scores and physiological variables, except for a lower rectal temperature in group M compared with the tramadol groups. After IN administration, tramadol was rapidly absorbed into the systemic circulation, reaching its maximum concentration (range 74.74-200.29 ng mL-1) within 30-60 minutes, it then decreased rapidly and was detectable in plasma for up to 2 hours after treatment in all dogs. CONCLUSIONS AND CLINICAL RELEVANCE: IN tramadol administration appears to be as effective as IV tramadol and methadone treatments in pain management of dogs after elective ovariohysterectomy. Given its low concentrations and short detection time in plasma after the IN route, systemic tramadol action appears unlikely.

Reproductive Traits of an Invasive Alien Population of Grey Squirrel (Sciurus carolinensis) in Central Italy.

The reproductive cycle of an invasive alien Italian grey squirrel population was studied to understand its adaptation and limit its spread, in order to conserve the autochthonous red squirrel. Female and male genital traits were evaluated throughout the reproductive cycle, including the ovary, uterus, testicle, epididymis, seminiferous tubule morphometry, and germinative epithelium histology. Moreover, individual female fecundity was determined by counting uterine scars. Ovary width and uterus weight, length, and width reached their highest values in the luteal and pregnancy phases. On conducting a histological evaluation of the testicular germinal epithelium, four morphotypes related to the different reproductive phases of the male squirrels were identified: immature, pubertal, spermatogenesis, and regressive. Testicle and epididymis weights and seminiferous tubule diameters reached their largest values during spermatogenesis. Uterine scar analysis showed that 69% of the females had given birth to one or two litters, while 31% had no uterine scars. Litters were larger in the first breeding period than in the second; annual fecundity was 4.52 ± 1.88 uterine scars/female. Umbrian grey squirrels have adapted to their non-native range, showing two annual mating periods at times similar to those in their native range, and high reproductive success.

Cystic thymic degeneration with pseudoepitheliomatous hyperplasia in a Beagle puppy: an idiopathic lesion?

A 6-mo-old female Beagle dog was inappetent and depressed. The radiographic, ultrasonographic, and computed tomographic examination of the chest revealed a 10 × 7 cm multicystic mediastinal structure interpreted as altered thymus, in association with moderate pleural effusion that laboratory tests confirmed as hemothorax. No history of trauma or anticoagulant drug intoxication was reported, and no coagulation disorders were detected. Afterward, medial cranial sternotomy was performed to remove the altered tissue. Histologically, this tissue was compatible with a thymic remnant, characterized by numerous cystic lesions, mostly blood filled and lined by flattened-to-cuboidal epithelial cells, occasionally projecting into the surrounding stroma, and forming cytokeratin-positive ribbons, trabeculae, and papillae. Lymphocytes were scant, and numerous areas of congestion and hemorrhage were present throughout the samples. This case of idiopathic thymic hemorrhage with cystic degeneration of the thymus and pseudoepitheliomatous hyperplasia was an incidental finding; the dog recovered from surgery uneventfully.