Journal of Comparative Pathology最新文献

{"title":"Histopathological, immunohistochemical and polymerase chain reaction diagnosis of Trypanosoma vivax in various organs of experimentally infected Creole sheep","authors":"Júlia Marques,&nbsp;Jéssica A. Withoeft,&nbsp;Gustavo W. Pandolfo,&nbsp;Luiz F.N. do Nascimento,&nbsp;Thierry G. de Cristo,&nbsp;Fabiano Z. Salbego,&nbsp;Joely F.F. Bittar,&nbsp;Renata A. Casagrande,&nbsp;Luiz C. Miletti","doi":"10.1016/j.jcpa.2026.06.008","DOIUrl":"10.1016/j.jcpa.2026.06.008","url":null,"abstract":"<div><div><em>Trypanosoma vivax</em> is one of the major species implicated in animal trypanosomoses in West Africa, significantly affecting livestock economies in Sub-Saharan Africa and also in endemic regions of South America. Post-mortem diagnosis of <em>T. vivax</em> remains challenging due to non-specific lesions and limitations of conventional parasitological and molecular techniques. This study aimed to evaluate and validate immunohistochemical approaches using polyclonal anti-<em>T. vivax</em> antibodies for the post-mortem diagnosis of <em>T. vivax</em> in formalin-fixed, paraffin wax-embedded tissues of experimentally infected Creole sheep, and to correlate the findings with histopathology and polymerase chain reaction (PCR) results. Twelve organs from three experimentally infected sheep were examined using histology and immunohistochemistry (IHC), and seven organs were additionally analysed by conventional PCR. IHC was performed successfully using two different detection systems targeting <em>T. vivax</em> trypomastigotes within tissue sections. Histologically, <em>T. vivax</em> was detected in various small and medium-sized blood vessels across multiple organs. The protozoan was immunolabelled in the kidneys, rete mirabile, lymph nodes, brain, pancreas, lungs and heart of only two sheep and was detectable in the blood vessels of the liver across all examined animals. This is the first experiment demonstrating immunolabelling of <em>T. vivax</em> in preserved tissues. The PCR findings showed that optimal results were achieved on individual technical triplicates of 100 ng or on a pooled sample of 300 ng. Overall, histology, IHC and PCR showed complementary diagnostic performance. The combined application of these techniques enhances the accuracy of post-mortem diagnosis of <em>T. vivax</em>, particularly under conditions where fresh blood samples are unavailable.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"228 ","pages":"Pages 75-84"},"PeriodicalIF":1.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148411929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Yersinia pseudotuberculosis infection in four free-ranging odontocetes","authors":"Nicholas J. Davison,&nbsp;Stephen A. Raverty,&nbsp;Els M. Broens,&nbsp;Andrew C. Brownlow,&nbsp;Mark P. Dagleish,&nbsp;Andrea Gröne,&nbsp;Marja J.L. Kik,&nbsp;Linde van Schalkwijk,&nbsp;Lonneke L. IJsseldijk","doi":"10.1016/j.jcpa.2026.05.008","DOIUrl":"10.1016/j.jcpa.2026.05.008","url":null,"abstract":"<div><div><em>Yersinia pseudotuberculosis</em> is a zoonotic pathogen that has been recovered from a variety of companion, production, laboratory, wildlife and avian species. The prevalence of this bacterium varies geographically but is generally considered widespread within the terrestrial environment with human exposure principally by ingestion of contaminated food or water. Pseudotuberculosis, due to <em>Y. pseudotuberculosis,</em> is a common cause of mortality in captive exotic birds and mammals and, according to the OIE WAHIS-Wild Interface, is the 8th most frequently reported disease/infection for all wildlife worldwide and the 5th in wild mammals. This report increases the number of recognized species susceptible to pseudotuberculosis and expands the environmental distribution of this bacterium into the marine habitat with four <em>Y</em>. <em>pseudotuberculosis</em> culture-positive cases in three odontocete species, including three from the North Sea and one from the northeastern Pacific Ocean. This case series is the first to report pseudotuberculosis in mammals that reside exclusively in the marine habitat. At present, there is insufficient information on the natural history of <em>Y. pseudotuberculosis</em> and marine mammal infections to infer whether exposure was due to terrestrial contamination of water courses or, alternatively, the bacterium persisting within the marine environment.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"228 ","pages":"Pages 85-91"},"PeriodicalIF":1.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148421405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pigmented dermal duct tumour (Winkelmann-McLeod type poroma) in a ring-tailed lemur (Lemur catta)","authors":"Tomomi Hashimoto,&nbsp;Takahiro Yamaki,&nbsp;Daisuke Hagihara,&nbsp;Akihiro Hirata,&nbsp;Mami Murakami,&nbsp;Hiroki Sakai","doi":"10.1016/j.jcpa.2026.06.002","DOIUrl":"10.1016/j.jcpa.2026.06.002","url":null,"abstract":"<div><div>A pigmented dermal duct tumour was diagnosed in a 12-year-old female ring-tailed lemur (<em>Lemur catta</em>) kept in a zoo. The tumour developed on the ventral surface of the left fourth digit and appeared as a black, solid, ulcerated nodule. Histologically, it was a well-demarcated, non-encapsulated dermal proliferation of basaloid neoplastic epithelial cells forming solid nests with scattered small duct-like lumina. Scattered melanocytes and abundant melanin pigment were present within the tumour. There was no continuity between the tumour and the epidermis.</div><div>Immunohistochemically, the basaloid neoplastic epithelial cells were positive for pan-cytokeratin and p63 but negative for cytokeratin 19, α-smooth muscle actin, vimentin, Sox10, DOG1, S100, PNL2 and Melan-A. Neoplastic luminal cells were positive for pan-cytokeratin and cytokeratin 19, but negative for p63. Based on the morphological and immunohistochemical findings, the tumour was diagnosed as a pigmented dermal duct tumour that corresponds to one of the subtypes of benign human poroid neoplasms. To our knowledge, this is the first report of this neoplasm in a ring-tailed lemur.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"228 ","pages":"Pages 53-55"},"PeriodicalIF":1.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148330054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pathogenesis of proliferative enteropathy caused by Lawsonia intracellularis","authors":"S. McOrist,&nbsp;S.M. Moore","doi":"10.1016/j.jcpa.2026.05.006","DOIUrl":"10.1016/j.jcpa.2026.05.006","url":null,"abstract":"<div><div>Proliferative enteropathy is a common infectious disease affecting pigs, horses and other animals; it is caused by <em>Lawsonia intracellularis</em>, an obligately intracellular bacterium. <em>Lawsonia</em> infection causes a distinctive pathological change, characterized by a rugose thickening of the intestinal mucosa, due to the adenomatous proliferation of immature intestinal crypt epithelial cells, with local depletion of goblet and enteroendocrine cells.</div><div>The disease has a low infectious dose; transmission occurs readily between young animals via oral contact with infected faecal material derived from other infected animals and the environment.</div><div>Intracellular <em>L. intracellularis</em> infection causes the transient amplifying epithelial cells in the crypts of the aboral intestine to fail to differentiate, leading to the distinctive adenomatous proliferation. This differentiation failure reflects <em>Lawsonia</em>'s ability to disrupt paracrine crosstalk signalling between epithelial cells and the layers of supporting cells surrounding each crypt. A working hypothesis is that the intracellular infection of transient amplifying cells in the crypt by <em>Lawsonia</em> disrupts the quiescence activity of bone morphogenetic protein at the crypt–villus junction zone.</div><div><em>Lawsonia</em> infection is a rare example of host tissue hyperplasia due to a reaction induced by a bacterium.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"228 ","pages":"Pages 37-44"},"PeriodicalIF":1.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148308247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Histomorphological features and ezrin expression in testicular seminomas in dogs: an association with potential prognostic value","authors":"Sara C. Pereira de Souza ,&nbsp;Maurício D. de Barros ,&nbsp;Bárbara P. dos Santos Batista ,&nbsp;Camila B. Amaral ,&nbsp;Ana M. Reis Ferreira ,&nbsp;Juliana da Silva Leite","doi":"10.1016/j.jcpa.2026.02.003","DOIUrl":"10.1016/j.jcpa.2026.02.003","url":null,"abstract":"<div><div>Seminoma (SEM) is one of the most frequent testicular neoplasms in dogs, originating from germ cell lineage of the seminiferous tubule and divided into diffuse and intratubular patterns, according to location. Periodic acid–Schiff (PAS) staining is used to classify human SEMs but there is no consensus regarding canine SEMs. Ezrin expression has been detected in several human neoplasms and is linked to a poor prognosis. However, its expression in testicular tumours is rarely described in human SEMs and no similar study was found in dogs. This study aimed to evaluate the presence of ezrin by immunohistochemical labelling and PAS staining in canine SEM samples, correlating them with histomorphological features. Twenty-three canine SEMs were subjected to PAS staining and anti-ezrin immunohistochemical analysis. Pink-magenta-stained samples were PAS positive. Percentage of ezrin immunolabelled positive cells, immunolabelling intensity and ezrin location were recorded. Intratubular SEMs were PAS positive but diffuse samples were PAS negative. Twenty cases (87%) were ezrin positive by cytoplasmic immunolabelling. Ezrin immunolabelling intensity was heterogeneous among tumour samples, similar to normal testicular tissue, but with different locations in each case. The percentage of positive cells was high in 18 cases and correlated positively with diffuse SEM. Ezrin immunolabelling correlated with cytoplasmic immunolocalisation, intensity and percentage of immunolabelled cells. This study confirmed differences in PAS staining for canine SEM patterns and ezrin immunolabelling in diffuse and intratubular canine SEMs, demonstrating ezrin's potential role in this testicular tumour in dogs. Diffuse canine SEM had local invasive features associated with ezrin immunolabelling. According to these findings, PAS staining correlates with canine SEM histomorphology and ezrin immunolabelling can be used as a biological marker of the local invasiveness potential of canine SEMs.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"226 ","pages":"Pages 57-63"},"PeriodicalIF":0.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147592577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Malignant ovarian granulosa cell tumour of corpus luteum origin in a California sea lion (Zalophus californianus)","authors":"Nancy Stedman ,&nbsp;Eric Gibbons ,&nbsp;Brittany Dolan ,&nbsp;Kara Abbott ,&nbsp;Jennifer Russell ,&nbsp;Todd Schmitt ,&nbsp;Kelsey Herrick","doi":"10.1016/j.jcpa.2026.03.001","DOIUrl":"10.1016/j.jcpa.2026.03.001","url":null,"abstract":"<div><div>A 19-year-old female California sea lion (<em>Zalophus californianus</em>) in managed care was euthanized following a 3-week history of hyporexia, diarrhoea, lethargy, abdominal discomfort, dyspnoea and tremors. Ante-mortem ultrasound confirmed splenomegaly with multifocal infiltrates and splenic aspirates revealed malignant cells of undetermined origin. Necropsy confirmed a malignant trabecular to diffuse granulosa cell tumour (GCT) that had metastasized to the liver, spleen, kidneys, adipose tissue, pancreas, adrenal glands, lungs, lymph nodes, brain and bone marrow. The GCT was arising within a corpus luteum and was not causing ovarian enlargement. A reticulin stain was useful to distinguish neoplastic granulosa cells from non-neoplastic cells of the corpus luteum. All neoplastic granulosa cells expressed vimentin and cytokeratin but few expressed inhibin alpha. The GCT had a mitotic count of 17 per 2.37 mm² and a Ki67 index of 85%. The sea lion delivered a stillborn pup 5 months prior to euthanasia, indicating the interval from tumour onset to severe metastatic disease was less than 5 months. The aggressive behaviour, high proliferation indices, origin of the neoplasm in a corpus luteum and lack of ovarian enlargement are unusual features for a GCT.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"226 ","pages":"Pages 20-23"},"PeriodicalIF":0.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147504149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A retrospective study (2019-2024) of neoplastic and non-neoplastic lesions in biopsy samples from exotic pet mammals in Hong Kong","authors":"Manar AbdelMageed ,&nbsp;Fraser I. Hill ,&nbsp;Jia Geng ,&nbsp;Fan Luo ,&nbsp;Wenzong He ,&nbsp;May Tse ,&nbsp;Steve Mills ,&nbsp;John Jardine ,&nbsp;Colin T. McDermott ,&nbsp;Ibrahim Elsohaby","doi":"10.1016/j.jcpa.2026.03.002","DOIUrl":"10.1016/j.jcpa.2026.03.002","url":null,"abstract":"<div><div>This retrospective study analysed pathological findings in tissue biopsies from eight exotic pet mammal species submitted to the CityU Veterinary Diagnostic Laboratory in Hong Kong between January 2019 and December 2024. Tissue biopsies were submitted from 287 rabbits, 161 hamsters, 131 hedgehogs, 64 guinea pigs, 22 chinchillas, 20 rats, seven mice and six ferrets. Across all investigated species, both neoplastic and non-neoplastic lesions were prevalent with species-specific tendencies in affected organ system. Skin and soft tissues, along with the reproductive system, were the most affected organ system in all investigated species. Except for chinchillas, neoplastic lesions outnumbered non-neoplastic lesions in all studied species. Adenocarcinoma (15.2%) mostly of the uterus and mammary gland was the most commonly diagnosed lesion in rabbits followed by trichoblastoma (14.5%). Adenoma (14.6%), mostly of the mammary gland, was the most frequently submitted lesion from hamsters, followed by lymphoma (9.8%). Sarcomas of uncertain differentiation were the most prevalent lesions in hedgehogs (21.4%) and were primarily cutaneous and uterine sarcomas, while cystic endometrial hyperplasia (CEH) ranked second (15.3%). In guinea pigs, CEH (21.5%) was the most commonly identified pathology followed by mammary adenoma (13.8%). The reproductive system accounted for more than half of the lesions diagnosed in chinchillas with CEH and endometritis being the most prevalent lesions, each representing 18.2% of submitted biopsies from chinchillas. Mammary gland fibroadenoma was the most frequent diagnosis in rats (55%) and equal in frequency with adenocarcinoma in mice, each representing 25% of submitted biopsies. Ferrets had seven distinct diagnoses. These findings emphasize the significance of reproductive and integumentary health in exotic pet mammals and reveal species-specific disease patterns critical for diagnosis and preventive care.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"226 ","pages":"Pages 24-37"},"PeriodicalIF":0.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147512331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ganglioneuroma in a Meller's chameleon (Trioceros melleri)","authors":"Freelie Mitchell ,&nbsp;Mary Ceccolini ,&nbsp;Robert V. Jones ,&nbsp;Elise E.B. LaDouceur","doi":"10.1016/j.jcpa.2026.01.008","DOIUrl":"10.1016/j.jcpa.2026.01.008","url":null,"abstract":"<div><div>Nervous system neoplasia is rarely reported in reptiles, with most reports representing gliomas. A captive, 9-year-old Meller's chameleon (<em>Trioceros melleri</em>) was euthanized for weight loss and lethargy. At necropsy, a 2 cm-diameter mass was effacing the right adrenal gland and adhered to the kidney. The skin had two, 0.8–1.0 cm-diameter, firm, pale-yellow masses over the right leg and left shoulder. The fat bodies were small. Histologically, the adrenal gland and peri-adrenal soft tissues were effaced by an expansile, moderately cellular neoplasm entrapping remnant chromaffin and interrenal cells and invading the kidney. The neoplasm was composed of two cell populations resembling well-differentiated neurons and Schwann cell-like peripheral nerve sheath elements. Cellular atypia was minimal. The skin was multifocally elevated and expanded by invasive, unencapsulated neoplasms composed of intersecting streams of neoplastic spindle cells with abundant eosinophilic, finely vacuolated cytoplasm, oval nuclei, marked anisocytosis and anisokaryosis, and occasional mitoses; these were interpreted as sarcomas. The fat bodies had marked atrophy. Immunohistochemistry was non-contributory (glial fibrillary acidic protein, neuron-specific enolase, synaptophysin, NeuN, chromogranin, S100 and vimentin) or negative (AE1/AE3) in neoplastic cells. The adrenal gland mass was diagnosed as a ganglioneuroma, which is a neoplasm of the peripheral nervous system originating from the sympathetic ganglia of the autotomic nervous system. Ganglioneuroma is rarely reported in veterinary species, and this is the first report in a reptile. The origin of this ganglioneuroma was likely neural crest cells of the adrenal gland. It is unknown whether the dermal masses were related to the ganglioneuroma or were unrelated sarcomas.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"226 ","pages":"Pages 38-41"},"PeriodicalIF":0.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147521204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A review of the pathology of herpesvirus infections in pinnipeds","authors":"Amy L. Robinson ,&nbsp;Laura Bianchessi ,&nbsp;Mara S. Rocchi ,&nbsp;Mark P. Dagleish","doi":"10.1016/j.jcpa.2026.01.007","DOIUrl":"10.1016/j.jcpa.2026.01.007","url":null,"abstract":"<div><div>Twenty-two herpesviruses, all within the family <em>Orthoherpesviridae</em> and belonging to the <em>Alphaherpesvirinae</em> (n = 3) and <em>Gammaherpesvirinae</em> (n = 19) subfamilies have been reported in 14 different pinniped species (n = 8 phocids, n = 5 otariids and n = 1 odobenid). This review critically assessed the purported pathology reported for herpesvirus infections and found a variety of lesions present dependent on both the herpesvirus and host species. Lesions included hepatic and adrenal necrosis, interstitial pneumonia, thyroid atrophy, lymphodepletion, lymphocytolysis, ulcerative stomatitis, glossitis with tonsilitis and dermatitis, necrotizing keratitis and, potentially, other ocular lesions also. Furthermore, specific individual gammaherpesvirus infections were linked to oncogeneses including urogenital carcinoma, diffuse large B cell lymphoma and B cell lymphoblastic lymphoma. However, for many herpesvirus infections the clinical significance, lesion association and definitive herpesvirus classification remain uncertain, the latter due to lack of sufficient genome data. For these reasons, identification of the definitive host species or even if separately reported herpesviruses are actually the same virus, remain challenging. More extensive genome sequencing is required to definitively identify and classify individual herpesvirus species along with sensitive and specific tools to visualize them within tissues to enable investigation of lesion association.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"226 ","pages":"Pages 42-56"},"PeriodicalIF":0.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147521122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-communicating abomasal (gastric) diverticulum in a 7-day-old bull calf: a case report","authors":"Cassandra M. Powers","doi":"10.1016/j.jcpa.2026.02.002","DOIUrl":"10.1016/j.jcpa.2026.02.002","url":null,"abstract":"<div><div>A gastric diverticulum (GD) is defined as an outpouching of the gastric wall and is reported rarely in humans, cats and dogs. A congenital GD (true GD) is a full-thickness diverticulum involving all gastric layers. A 7-day-old bull calf with a history of sudden death was presented for post-mortem examination to the Purdue Animal Disease Diagnostic Laboratory. On gross examination, arising from the wall of the caudal aspect of the greater curvature of the abomasum was a soft to firm hollow mass with no gross evidence of communication with the abomasal lumen. Histological sections of the mass revealed a full-thickness GD that possessed all four layers of the abomasum including segments of normal abomasal epithelium. The rumen, reticulum and omasum remain undeveloped at birth and during the first few weeks of life. A calf's rumen usually develops fully at around 12 weeks of age and the abomasum does not reach its maximum volume until around 1.5 years of age. Therefore, it is possible that this calf was either born with this anomaly or it may have developed and closed completely during early post-natal development of the forestomaches. As far as the author is aware, this is the first reported case of an abomasal diverticulum in a bovid.</div></div>","PeriodicalId":15520,"journal":{"name":"Journal of Comparative Pathology","volume":"225 ","pages":"Pages 10-12"},"PeriodicalIF":0.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147321585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}