Case summary A 9-year-old, spayed, female domestic shorthair cat presented with an open wound approximately 1 cm in size with exposure of the left subcutaneous ureteral bypass (SUB) shunting port that was placed approximately 11 months before presentation. Primary closures were attempted twice before local wound management with omentalisation and repositioning of the port. The exposed port was lavaged topically with a polyhexanide and propylbetaine wound irrigation solution before omentalisation and repositioning, resulting in successful retention of the implant. Five months after revision and omentalisation, there was complete coverage and healing of the wound.

Relevance and novel information Adequate topical treatment, repositioning and omentalisation could be a successful treatment option for the uncommon complication of SUB shunting port extrusion secondary to resistant local infection originating from the urinary tract.

Case summary A 5-month-old male castrated domestic shorthair cat was evaluated for acute onset of emesis. Abdominal radiographs identified a suspected colonic foreign body and abdominal-focused assessment with sonography for trauma, triage and tracking (AFAST) evaluation revealed a large amount of peritoneal effusion. Cytology of the peritoneal effusion was consistent with a septic exudate. An exploratory celiotomy identified a ruptured ileocecocolic mass and a resection and anastomosis was performed. No foreign material was identified and histopathology confirmed that the ruptured mass was a colonic duplication cyst. Recurrent septic peritonitis was diagnosed based on cytologic evaluation of fluid from a silicone bulb reservoir of a closed suction drain. No abnormalities were surgically identified, the cat recovered without complication, was discharged at 7 days postoperatively and has continued to remain healthy 8 months after surgical intervention.

Relevance and novel information To our knowledge, this is the first known instance of a histopathologically confirmed non-communicating colonic duplication cyst causing septic peritonitis in the veterinary literature.

Case summary This report describes the diagnostic findings, natural history and genetic analysis of the candidate gene Forkhead Box F1 (FOXF1) in a young cat with developmental lung disease and high probability of pulmonary hypertension. A 1-year-old male entire Chartreux cat was referred for cardiac murmur investigation and exercise intolerance. Echocardiography identified a high-velocity tricuspid regurgitant jet with right-sided cardiac changes, supporting a high probability of pulmonary hypertension. No congenital cardiac shunts or left-sided cardiac changes were found to support a primary cardiac cause of pulmonary hypertension. Extensive laboratory work, thoracic radiographs and CT were performed. Histopathological characterisation (lung biopsy and later post mortem) was necessary to reach the final diagnosis. Eight months after diagnosis, the cat developed right-sided congestive heart failure, eventually leading to euthanasia. Survival from diagnosis to death was 12 months.

Relevance and novel information Developmental lung disease belongs to a group of diffuse lung diseases in humans associated with pulmonary hypertension. The veterinary literature describing lung growth disorders in cats is sparse, and the present report provides information on clinical presentation and progression alongside a thorough diagnostic workup, which may aid clinicians in identifying this condition. Lung biopsy was pivotal in reaching the final diagnosis. No causal variants in FOXF1 were identified.

Case summary A 2-year-old domestic shorthair queen sustained a tear in the vaginal wall through which the queen herniated a fetus during parturition. An exploratory laparotomy was performed, the patient had an ovariohysterectomy and the fetus was removed vaginally. The tear was managed medically with antibiotics, analgesics and careful monitoring. Assessment of the injury site 2 weeks later confirmed successful healing without the need for surgical intervention in the vaginal wall.

Relevance and novel information This is the first report in veterinary medicine describing the successful medical management of a dystocia-related vaginal wall tear in a feline patient without surgical repair.

Case summary An 11-year-old female neutered domestic shorthair cat was referred for surgical management of a traumatic right stifle luxation. Orthopaedic examination of the affected stifle under general anaesthesia revealed joint effusion and craniocaudal and rotational instability. Cranial displacement of the tibia with respect to the femur and infrapatellar pad sign were identified on radiography. Intraoperatively, complete rupture of both cruciate ligaments and marked disruption of the mid and caudal poles of the medial and lateral menisci were observed. Both collateral ligaments appeared intact. The remnants of the injured cruciate ligaments were removed, and medial and lateral caudal hemimeniscectomies were performed. A tibial plateau levelling osteotomy (TPLO) was performed to address the craniocaudal stifle instability. Intraoperative assessment of the stifle revealed persistent instability with cranial tibial translation, internal and external rotation, and a positive caudal draw test. A lateral augmentation suture was employed to address the persistent cranial tibial translation and internal rotation. To successfully neutralise caudocranial and external rotational instability secondary to the caudal cruciate ligament deficiency, a medial augmentation suture was placed with the aid of three interference screws. Stifle stability was achieved. A modified Robert-Jones bandage was kept on for 24 h postoperatively. An excellent outcome was achieved, with successful limb function restoration.

Relevance and novel information This case report represents the first documented instance of feline traumatic stifle luxation repair by combining a corrective tibial osteotomy and extra-articular augmentation. Notably, it introduces the novel technique of implementing a TPLO with medial and lateral augmentation sutures to address multidirectional stifle instability.

Case summary A 1-year-old male neutered domestic shorthair cat presented on an emergency basis with clinical signs suspected to be secondary to organophosphate (OP) toxicity. The control of clinical abnormalities (bradycardia, obtundation, tachypnea, anorexia) was achieved using high-dose continuous rate intravenous infusion (CRI) of atropine sulfate (maximum rate 0.1 mg/kg/h). After 5 days of hospitalization, the patient made a full clinical recovery without the development of atropine toxicity, intermediate syndrome or delayed polyneuropathy at 4 weeks after discharge.

Relevance and novel information Treatment of OP toxicity in cats is sparsely reported in veterinary literature. Current standards of treatment and published protocols recommend the use of atropine sulfate as intermittent boluses for the treatment of muscarinic signs of toxicity; however, there is a paucity of information regarding the safety and efficacy of atropine sulfate as a CRI for severe toxicosis as described in humans. This report includes the first published case using such a treatment protocol in a cat.

Case summary A 5-year-old neutered Somali cat presented with a 2-week history of icterus. Diagnostic imaging revealed extrahepatic biliary obstruction (EHBO) due to a common bile duct (CBD) mass. During exploratory laparotomy, a duodenal perforation was discovered incidentally. Choledochoduodenostomy combined with the Billroth II procedure was performed after resection of the CBD mass and the proximal duodenum to treat the EHBO and duodenal perforation. Based on histological and immunohistochemical findings, the CBD mass was diagnosed as a neuroendocrine carcinoma with gastrin-producing cell differentiation. The cat recovered almost uneventfully and was discharged 11 days after surgery. The cat survived for nearly 100 days without recurrence of EHBO or duodenal perforation; however, intermittent vomiting and weight loss persisted despite supportive medications.

Relevance and novel information To the best of our knowledge, there is no detailed report on the application of choledochoduodenostomy combined with the Billroth II procedure in cats, as we used to treat the EHBO and duodenal perforation in the present case. As serum gastrin concentrations were elevated on the first day of hospitalisation, the CBD mass was diagnosed as a neuroendocrine carcinoma with gastrin-producing cell differentiation, which seemed to have caused not only EHBO but also duodenal perforation (Zollinger–Ellison syndrome). The cat survived for almost 100 days without any perioperative complications. However, this combined procedure might be considered as only a salvage option and not as a definitive treatment option in cats requiring simultaneous biliary and gastrointestinal reconstruction because postoperative supportive care could not improve the cat’s condition or maintain its quality of life.

Case summary An 8-year-old spayed female mixed-breed cat presented with a 2-year history of recurrent vomiting and hyporexia. Physical examination revealed a palpable mass in the mesogastric abdominal region without discomfort upon touch. Abdominal ultrasonography revealed an intramural mass in the small intestine (duodenum) that caused a decrease in the segment lumen. A complete blood count revealed leukocytosis with marked neutrophilia, eosinophilia and mild hypoalbuminemia. Enterectomy was performed with 3 cm margins and end-to-end anastomosis at the duodenal site of the mass. Histology revealed neoplastic elongated spindle cells that were poorly confined, originating within the muscle layers and that had a mitotic index of 2/10 high-power field (hpf) (at 400×), human epidermal growth factor receptor-type 2 (HER-2) supporting the diagnosis of low-grade sarcoma. Immunohistochemical analysis was positive for KIT, confirming a gastrointestinal stromal tumor (GIST) with a Ki67 level of 15%. Furthermore, multikinase profile biomarkers revealed that the neoplastic cells expressed HER-2 (65%), epidermal growth factor receptor-1 (50%), vascular endothelial growth factor receptor 2 (35%), platelet-derived growth factor receptor beta (15%) and c-KIT (15%). Six months after the original surgery, CT revealed presumptive hepatic, splenic and peritoneal metastases. Toceranib phosphate was prescribed at a dose of 2.75 mg/kg and progressive disease was observed at 8 weeks of follow-up.

Relevance and novel information To the best of our knowledge, this is the first case report to characterize the proliferation biomarker profile of a feline GIST in veterinary oncology. However, despite KIT expression in this tumor, the target drug did not inhibit tumor proliferation, providing new insights into this rare tumor in the feline species.

Case summary A 1-year-old female intact Scottish Fold cat was presented with a 1-month history of excessive hair shedding with white scales on the coat without pruritus. The cat lived mostly indoors and had no history of any systemic disease. Dermatological examinations were performed step by step. Several Demodex gatoi were identified from cellophane tape impressions from the scales and examined under a low-power objective (10×) microscope. Skin cytology showed keratinocytes without any microorganisms. Based on the findings, fluralaner (Bravecto for cats; MSD) spot-on was used once every 12 weeks for ectoparasiticidal control. An essential fatty acid supplement was recommended to repair and restore the coat and skin barrier. After 4 weeks of treatment, the cat showed substantial improvement, with a normal coat and no scales. Re-examination using a cellophane tape impression for mites was negative. Ectoparasitic control is highly recommended regularly for the treatment and prevention of ectoparasites.

Relevance and novel information Feline demodicosis is an uncommon parasitic dermatosis with primary clinical signs that may cause generalised or localised dermatitis with frequent pruritus, erythema and alopecia. The aims of this study were to report on dermatological lesions with excessive hair shedding and scales in a cat that were caused by demodicosis, without presenting the main clinical sign of pruritus or overgrooming. In addition, to the authors’ knowledge, this is the first report of the successful treatment of demodicosis due to D gatoi infestation with fluralaner single spot-on in an off-label use that was safe and easy to apply clinically.

Case summary A 10-year-old neutered male domestic shorthair cat was presented with an abdominal mass, associated renal failure, chronic vomiting, anorexia and progressive polyuria/polydipsia lasting for 3 weeks. Clinical examination and initial blood work revealed azotaemia, hypokalaemia and hypertension. Abdominal ultrasound showed an adrenal mass with a diameter of 3 cm near the right kidney. High serum aldosterone suggested primary hyperaldosteronism. Surgery enabled identification of the mass and its excision along with the right adrenal gland. Histologically, carcinoma of the adrenal cortex was diagnosed. Postoperatively, an increase in serum creatinine and potassium, along with a low serum aldosterone, led to a diagnosis of hypoaldosteronism. Mineralocorticoid therapy for 6 months was necessary, resulting in clinical and biological improvement.

Relevance and novel information To our knowledge, this case describes the longest-lasting reported secondary hypoaldosteronism in a cat, after unilateral adrenalectomy for an adrenal carcinoma with hyperaldosteronism.

Case summary A 10-year-old male neutered domestic shorthair cat, which had previously had its contralateral pelvic limb amputated, was treated for coxofemoral degenerative joint disease (DJD) with a total hip replacement. The long-term outcome was favourable and no complications were recorded. Interestingly, the contralateral coxofemoral joint left at the time of the previous amputation developed DJD and became a source of pain for the cat and was subsequently excised.

Relevance and novel information This case report shows that total hip replacement is a viable option in cats with coxofemoral DJD and a contralateral limb amputation. Retained joints in amputated limbs may develop osteoarthritis and be a source of pain for a cat.

Case summary A 7-year-old domestic shorthair cat was presented for periuria, apathy, fever, inappetence, diarrhoea and vomiting. A complete blood count and biochemistry analysis revealed severe thrombocytopenia, severe azotaemia, moderate panhypoproteinemia, mildly elevated DGGR lipase activity and mildly elevated liver enzyme activity. Abdominal ultrasound showed a hypoechoic pancreas with surrounding hyperechoic fat demonstrating dirty shadowing and ascites (protein-poor transudate). The cat was treated medically for pancreatitis with fluid therapy, antiemetics and pain medication. During the hospitalisation period, the cat developed severe anaemia and received multiple whole blood transfusions yet showed no signs of clinical improvement. A repeat ultrasound examination performed after 8 days showed progressive pancreatic lesions and ongoing ascites. Analysis of the free abdominal fluid revealed neutrophilic inflammation despite low protein and cell concentration, with the presence of numerous very small, coccoid, basophilic inclusions within neutrophils, raising the concern for a septic peritonitis due to Mycoplasma species. Quantitative PCR (qPCR) confirmed the presence of Mycoplasma felis. After 10 days of hospitalisation, the cat developed refractory septic shock and was euthanased. Necropsy revealed severe necrotising pancreatitis with systemic changes consistent with sepsis and microthrombi. qPCR testing for M felis in pancreatic tissue also yielded a positive result.

Relevance and novel information Although pancreatitis is a common disease in cats, this case report presents the first documented occurrence of M felis as the suspected primary pathogen causing pancreatitis in a cat.

Objectives The objective of this study was to determine the prevalence of Toxoplasma gondii IgM and IgG positive cats in Los Angeles County, California. T gondii antibodies are common in sera from cats in most reported studies around the world. Although the majority of infected cats never develop clinical disease, development of acute infection and recrudescence of latent infection secondary to immunosuppression has been reported. Knowledge of the serologic status of T gondii may be important when considering immunosuppressive treatments.

Methods T gondii IgM and IgG antibody titers were measured in 225 cats. Sera from owned cats tested at a multispecialty veterinary hospital were included both retrospectively and prospectively (n = 125). Sera from feral cats tested through a collaborating humane society were included prospectively (n = 100).

Results Of the 13 (5.8%) cats with IgM titers, 10 were positive at the minimal cut-off titer (1:64), one cat was clinically ill and none were currently positive for IgG antibodies, suggesting false-positive results for nine cats, giving an adjusted IgM prevalence rate of 1.8% (95% CI 0.7–4.5). A total of five (2.2%) cats were positive for IgG antibodies and no cat was positive for both antibodies.

Conclusions and relevance Most studies of T gondii antibodies in cat sera from California have shown higher prevalence rates, suggesting the cats in this municipality have a low risk of exposure. The study emphasizes that serological test results do not necessarily correlate to the presence of clinical illness.

Case summary A domestic shorthair cat presented to the Animal Referral Hospital (Brisbane, Australia) after having the left pelvic limb incorrectly amputated. The cat was unable to ambulate on the remaining right pelvic limb due to a chronically subluxated stifle. A stifle arthrodesis was performed on the right pelvic limb to manage the injury. Follow-up radiographs performed 5 months postoperatively demonstrated stifle arthrodesis with no detectable complications. The owner reported that aside from some difficulties in toileting, the cat had a good quality of life and was capable of performing the majority of daily activities. Stifle arthrodesis in a feline pelvic limb amputee appears to be a viable treatment option. After a period of rehabilitation and adaptation, the cat in the case report has been able to lead a near-normal lifestyle.

Relevance and novel information To the authors’ knowledge, this is the first report of the outcome and complications associated with stifle arthrodesis in a feline pelvic limb amputee. This is also the first report of stifle arthrodesis in a cat using the bilateral plating technique.

Case summary The patient was a castrated male American Shorthair cat, approximately 14 years old, weighing 3.4 kg. The patient had chronic kidney disease (CKD) (International Renal Interest Society stages 3–4) as an underlying disease. The cat was examined at a hospital for intermittent lethargy and seizures. Hypoglycaemia was repeatedly observed, and the insulin level was 1.78 ng/ml (reference interval 0.27–0.69) when the blood glucose was 49 mg/dl. Although the cat was tentatively diagnosed with insulinoma, surgery was not recommended because of the severe CKD. Although frequent feeding and prednisolone treatment were initially attempted, blood glucose decreased to 24–42 mg/dl. Diazoxide was additionally prescribed at a dose of 5.2 mg/kg q12h. The cat’s clinical signs improved, and the blood glucose was in the range of 75–103 mg/dl during the first 2 months. It was maintained at >50 mg/dl until the patient died of renal failure 161 days after the start of diazoxide treatment. With regard to adverse events, vomiting once every 2–3 days without weight loss and non-regenerative anaemia were observed, which might have been at least partially caused by diazoxide treatment. An insulinoma was definitively diagnosed via pathological autopsy.

Relevance and novel information This is the first reported case of long-term treatment with diazoxide in a cat with insulinoma. Since it was effective in situations where conventional therapies were unsuccessful, diazoxide could be useful as a new therapeutic option for cats with insulinoma. Since adverse events, such as progression of vomiting frequency and non-regenerative anaemia, were observed, careful monitoring was required during administration.

Case summary A 10-year-old male castrated domestic shorthair cat was presented for evaluation of a 3-day history of increased inspiratory effort. The cat had received prednisolone 1 mg/kg PO q24h for 1 year due to chronic diarrhea. On physical examination, the patient exhibited severe stridor, intermittent open-mouth breathing and bilateral mucopurulent nasal discharge. Subcutaneous emphysema was palpated over the dorsal cervical region. Mild hypoventilation (PvCO₂ 55.1 mmHg; approximate reference interval 35–45 mmHg) was identified. Cervicothoracic radiographs showed marked gas tracking within cervical soft tissues with concurrent laryngeal thickening, pulmonary nodules, a bronchial pulmonary pattern, pneumomediastinum and aerophagia. The cat was hospitalized and treated overnight with oxygen and intravenous fluid therapy before anesthesia the next day. On laryngoscopy, a large tracheal mass was observed arising from the right subglottic region and was removed using biopsy forceps. CT revealed an additional mass at the level of the tracheal bifurcation causing marked luminal narrowing of the trachea and proximal main bronchi. The cat made a good initial recovery, although moderate stridor persisted. Five days later, the cat was re-examined due to recurrence of respiratory distress and orthopnea, and the owner elected euthanasia. Histopathology revealed severe nodular obstructive eosinophilic plasmacytic laryngotracheitis with intranuclear inclusion bodies positive for feline herpesvirus-1 on immunohistochemistry.

Relevance and novel information This report describes the presentation and management of a cat with respiratory distress secondary to intratracheal eosinophilic masses caused by feline herpesvirus-1. Although the outcome was ultimately unsatisfactory, to the authors’ knowledge, this clinical presentation has not been previously reported.

Case series summary Cystic bronchiectasis was diagnosed in three cats with known histories of chronic coughing using CT and histopathology. CT of the lungs revealed large space-occupying lesions that compressed and displaced unaffected pulmonary parenchyma and vessels. The masses were soft tissue attenuating in two cases and gas-cavitated with areas of dependent fluid in one case. All three cats were found to have mineral attenuating material in lesions and in other dilatated airways. Generalized bronchial wall thickening was also present and indicative of chronic lower airway disease. These findings were supported by histopathology showing inflammatory changes and dilatated airways in the collected tissues. In the two cases in which post-contrast CT series were acquired, the lesions had rim-enhancement.

Relevance and novel information Cystic bronchiectasis is a rare presentation of bronchiectasis in cats and may mimic a pulmonary mass lesion, which could be mistaken for neoplasia or abscessation. The lack of central enhancement or presence of gas cavitation on CT, concurrent presence of diffuse bronchial wall thickening, other areas of bronchiectasis and the presence of broncholithiasis may alert the clinician to the possibility of cystic bronchiectasis related to chronic lower airway disease.

Case summary This report describes the case of a 7-year-old male neutered domestic mixed-breed cat that was initially referred to the Veterinary Hospital of the State University of Londrina for evaluation of a 2-week history of abdominal distension and a 2-day history of anorexia, infected with feline immunodeficiency virus (FIV). Abdominal ultrasound revealed an expansive mass located around the pancreas and right hepatic lobe. In the transoperative macroscopic observation, multiple white nodules were visualized in the liver, pancreas, mesentery, intestine, stomach and peritoneal wall. Immunohistochemical examination revealed that neoplastic cells demonstrated a strong positivity for AE1/AE3 and CK20. A sparse immunoreactivity to chromogranin A was observed, which demonstrates neuroendocrine cell labeling. The histopathologic changes associated with the immunohistochemical profile confirmed the diagnosis of metastatic carcinoma with neuroendocrine differentiation, originating from the pancreas.

Relevance and novel information Neuroendocrine tumors of the pancreas are rare and are associated with a poor prognosis in humans. In humans, approximately 7% of neuroendocrine tumors develop in the pancreas, and the 5-year survival rate for a pancreatic neuroendocrine tumor is 53%, according to the American Cancer Society. To our knowledge, only one case has been described in the feline species so far. Due to the rarity of this type of tumor in cats, there is little information about predisposition related to age, sex or breed, as well as the main clinical signs presented, survival time and treatment options.

Case series summary A 1-year-old castrated male domestic shorthair cat was suspected with myasthenia gravis (MG) based on neurological examination, complete blood count (CBC), serum biochemistry, radiography and electrophysiological examination. In addition, a 9-year-old spayed female domestic shorthair cat was diagnosed with MG based on neurological examination, CBC, serum biochemistry, radiography, ultrasonography and increased acetylcholine receptor antibody titre. Positioning head tilt (PHT) was observed at the time of diagnosis in both cats.

Relevance and novel information Although the pathophysiology of PHT in cats is not fully understood, the mechanism for PHT in cats with MG may be similar to that of cats with hypokalaemic myopathy, supporting our hypothesis that muscle spindle dysfunction causes PHT.