Francesco Marchesi

Osteosarcoma (OSA) is the most common primary bone tumor in dogs and cats, and accurate diagnosis of OSA has therapeutic and prognostic implications. Immunohistochemistry targeting osterix (Osx), a transcription factor expressed in osteoblasts, was applied to 80 canine samples (40 OSAs and 40 controls (8 chondrosarcomas, 8 fibrosarcomas, 8 hemangiosarcomas, 8 histiocytic sarcomas, and 8 malignant melanomas)) and 40 feline samples (20 OSAs and 20 controls (5 fibrosarcomas, 5 hemangiosarcomas, 5 chondrosarcomas, 3 malignant melanomas, and 2 histiocytic sarcomas)), diagnosed histologically. All 120 samples were assessed blinded using a previously established semiquantitative scoring and classification system. In dogs, 37/40 OSAs (true positives, sensitivity 92.5%) and 2/40 controls (false positives, specificity 95.0%) were classified as OSA. In cats, 14/20 OSAs (true positives, sensitivity 70.0%) and 5/20 controls (false positives, specificity 75.0%) were classified as OSA. Tumors most often “misclassified” as OSAs were chondrosarcomas in both dogs (2/8) and cats (4/5). In 4 cases for which paired decalcified and nondecalcified samples of the same OSA were available, decalcification of OSAs did not affect classification. Quiescent canine, feline, and murine osteoblasts and canine reactive, metaplastic, and non-OSA neoplastic osseous conditions were also tested and demonstrated Osx immunoreactivity; avian and piscine osteoblasts did not. In conclusion, Osx is a highly sensitive and specific marker of canine OSA and a moderately sensitive and specific marker of feline OSA. The diagnostic algorithm applied in this study is a useful adjunctive tool in the diagnosis of canine OSA.

A 1‐year‐old, male, neutered Bernese Mountain dog presented with a 2‐week history of acute‐onset progressive signs of right C6–T2 myelopathy and neck pain. Magnetic resonance imaging of the cervical vertebral column revealed a right‐sided extradural mass at the level of the C6 vertebra causing severe spinal cord compression. A right C5–C7 modified dorsal laminectomy was performed to remove the mass, resulting in its complete excision, except for residual tissue attachments to the ligamentum flavum. Successful spinal cord decompression was achieved, as confirmed by postoperative magnetic resonance imaging. Histopathology and immunochemistry showed a proliferative lesion dominated by a mixture of spindle and histiocytic cells, with associated infiltrates of T‐lymphocytes, B‐lymphocytes and plasma cells suggestive of an inflammatory pseudotumour. Subsequently, the dog underwent a 2‐month course of prednisolone treatment and showed complete recovery. At the 2‐year follow‐up, the dog was neurologically normal.

A 7 yr old female neutered domestic shorthair was presented with a 2 mo history of lethargy and hyporexia progressing to anorexia. Initial diagnostics indicated pancreatitis with secondary hepatic lipidosis. Supportive care, including the placement of an esophageal feeding tube, was initiated. The feeding tube was removed traumatically by the cat and thus replaced. The cat acutely deteriorated while hospitalized, developing marked hypersalivation and an obtunded mentation. Radiographs were taken to confirm placement of the feeding tube in case tube dislodgement was contributing to the hypersalivation; results confirmed appropriate positioning and gastric pneumatosis. Despite intensified medical management, the patient suffered cardiopulmonary arrest 7 days after hospital admission. Post-mortem examination confirmed necrotizing gastritis with emphysema alongside segmental mucosal necrosis in the jejunum, focal pancreatic necrosis, and diffuse hepatic lipidosis. Gas in the gastric wall is a rare finding in veterinary medicine and can arise due to gastric pneumatosis or emphysematous gastritis; there are scant reports of either in feline medicine. This report documents a case of emphysematous gastritis in a cat with concurrent pancreatitis and hepatic lipidosis. The cat developed emphysematous gastritis without undergoing gastrointestinal surgery which is currently the only reported feline predis-posing factor for development.

Human African Trypanosomiasis (HAT) has been responsible for several deadly epidemics throughout the 20th century, but a renewed commitment to disease control has significantly reduced new cases and motivated a target for the elimination of Trypanosoma brucei gambiense-HAT by 2030. However, the recent identification of latent human infections, and the detection of trypanosomes in extravascular tissues hidden from current diagnostic tools, such as the skin, has added new complexity to identifying infected individuals. New and improved diagnostic tests to detect Trypanosoma brucei infection by interrogating the skin are therefore needed. Recent advances have improved the cost, sensitivity and portability of Raman spectroscopy technology for non-invasive medical diagnostics, making it an attractive tool for gambiense-HAT detection. The aim of this work was to assess and develop a new non-invasive diagnostic method for T. brucei through Raman spectroscopy of the skin. Infections were performed in an established murine disease model using the animal-infective Trypanosoma brucei brucei subspecies. The skin of infected and matched control mice was scrutinized ex vivo using a confocal Raman microscope with 532 nm excitation and in situ at 785 nm excitation with a portable field-compatible instrument. Spectral evaluation and Principal Component Analysis confirmed discrimination of T. brucei-infected from uninfected tissue, and a characterisation of biochemical changes in lipids and proteins in parasite-infected skin indicated by prominent Raman peak intensities was performed. This study is the first to demonstrate the application of Raman spectroscopy for the detection of T. brucei by targeting the skin of the host. The technique has significant potential to discriminate between infected and non-infected tissue and could represent a unique, non-invasive diagnostic tool in the goal for elimination of gambiense-HAT as well as for Animal African Trypanosomiasis (AAT).

Summary: An 11‐year‐old crossbreed mare was presented with a nodular, pink mass at the temporal corneolimbal junction of the right eye. Histopathology confirmed the diagnosis of invasive squamous cell carcinoma. The mare underwent lamellar keratectomy and conjunctivectomy under general anaesthesia, followed by adjunctive topical chemotherapy with 1% 5‐fluorouracil solution for 10 days post‐operatively. Adverse effects included moderate conjunctival inflammation and exuberant granulation tissue formation at the surgical site, responding to surgical debulking and topical corticosteroid application. No mass regrowth was present at 12 months following discharge. This report describes the successful use of topical 1% 5‐FU as an adjunctive treatment for equine ocular squamous cell carcinoma.

Canine lymphoma represents a heterogeneous group of lymphoid neoplasms, with multicentric nodal lymphoma being the most common presentation. Musculoskeletal involvement is uncommon, and primary muscular lymphoma is a very rare presentation. Only a few cases have been described in dogs, which were of variable classification and immunophenotype. Here, we report the case of a 5-year-old female neutered Beagle that presented with an intramuscular mass on the right shoulder and associated lameness and lethargy. One month after initial presentation, multiple cutaneous nodules appeared on the head, and staging with advanced imaging revealed additional masses affecting other muscles. Cytology, histopathology, immunohistochemistry, and PCR for antigen receptor rearrangements of one of the muscle masses and skin lesions supported a diagnosis of peripheral T-cell lymphoma with large granular lymphocytes at both sites. The dog was euthanized after diagnosis due to the poor prognosis. This is the first report of primary muscular peripheral T-cell lymphoma with large granular lymphocytes and cutaneous involvement in the dog. Despite being a rare presentation, lymphoma must be considered a differential in dogs presenting with a discrete, intramuscular, soft tissue mass.

We report that TLR7, IL-6, and the adaptive immune system are essential for autoimmunity and glomerulonephritis but not for liver pathology in mice expressing the ubiquitin-binding–defective ABIN1[D485N] mutant. The blood and organs of ABIN1[D485N] mice have exceptionally high numbers of patrolling monocytes (pMo), which develop independently of IL-6 and the adaptive immune system. They are detectable in the blood months before autoimmunity and organ pathology are seen and may have diagnostic potential. The splenic pMo, inflammatory monocytes (iMo), and neutrophils of ABIN1[D485N] mice expressed high levels of mRNAs encoding proteins released during NETosis, which together with the high numbers of monocyte-derived dendritic cells (MoDCs) may drive the liver pathology in ABIN1[D485N] mice, and contribute to the pathology of other organs. The splenic iMo of ABIN1[D485N] mice displayed high expression of mRNAs encoding proteins controlling cell division and were actively dividing; this may underlie the increased pMo and MoDC numbers, which are derived from iMo. An orally active IRAK4 inhibitor suppressed all facets of the disease phenotype and prevented the increase in pMo numbers.

Polymorphisms in the TNIP1 gene encoding A20-binding inhibitor of NF-κB1 (ABIN1) predispose to lupus and other autoimmune diseases in at least eight human populations. We found previously that knock-in mice expressing a ubiquitin-binding–defective mutant of ABIN1 (ABIN1[D485N]) develop autoimmunity as they age and succumb to a disease resembling lupus nephritis in humans. In this article, we report that Flt3-derived dendritic cells from these mice overproduced type 1 IFNs upon stimulation with ligands that activate TLR7 or TLR9. However, crossing ABIN1[D485N] mice to IFNAR1-knockout mice that do not express the α-subunit of the type 1 IFNR did not prevent splenomegaly, the appearance of high serum levels of autoantibodies and other Igs, or liver inflammation and only reduced kidney inflammation modestly. In contrast, crossing ABIN1[D485N] mice to knock-in mice expressing catalytically inactive mutants of IRAK1 or IRAK4 prevented splenomegaly, autoimmunity, and liver and kidney inflammation. Our results support the notion that IRAK1 and/or IRAK4 are attractive targets for the development of drugs to prevent, and perhaps treat, lupus nephritis and other autoinflammatory diseases caused by the decreased ability of ABIN1 or other proteins to restrict the strength of MyD88 signaling.

Eosinophilic crystals have been described in the upper and lower respiratory tract, gall bladder, intrahepatic bile ducts and glandular stomach of different laboratory mice strains. They have been recently identified as chitinase–like (Ym1/Ym2) proteins. Here we describe the occurrence of eosinophilic crystals in the renal tubules of mice with experimentally induced acute myelogenous leukaemia. Fourteen FVB/N and 29 129Sv mice of both sexes, 8–10 weeks of age, were employed to establish a model of human acute myelogenous leukaemia. Nine mice that developed a widespread acute myelogenous leukaemia revealed the presence of eosinophilic crystals in renal tubules. The presence of eosinophilic crystals in the kidneys was constantly associated with a hyaline droplet nephropathy. Immunohistochemistry showed that the crystals and the hyaline droplets were composed of chitinase‐like (Ym1/Ym2) proteins. Furthermore, immunoreactivity for Ym1/Ym2 proteins was also detected in the crystalline material stored in the cytoplasm of large macrophage‐like cells or in extracellular localization within the leukaemic infiltrates. On the basis of our results we hypothesize that the detection of the Ym1/Ym2 proteins in the urine of mice might represent a feasible indicator of the burden and progression of the leukaemic condition in our murine model.