Clinical presentation and short-term outcomes of dogs ≥15 kg with extrahepatic portosystemic shunts.

OBJECTIVE: To describe demographics, clinical presentation, shunt anatomy, clinical progression, and complications in large dogs ≥15 kg with single extrahepatic portosystemic shunts (EHPSS) treated with or without surgery. STUDY DESIGN: Multicenter retrospective (10 university hospitals, one private referral institution). ANIMALS: Dogs ≥15 kg (n = 63). METHODS: Medical records of dogs ≥15 kg diagnosed with EHPSS between January 01, 2005 and December 31, 2020 were reviewed. Dogs had a minimum follow-up of 90 days. Signalment, clinical signs, diagnostics, shunt anatomy, treatment interventions, and perioperative complications were assessed. RESULTS: Median age was 21.9 months (IQR: 9-36.8). The breed most represented was the Golden retriever (17/63 dogs). Portocaval (17/63) and splenocaval (15/63) shunt configurations were most common. Portal vein hypoplasia was noted in 18 imaging reports. Of the surgically treated dogs, 14/45 (35.6%) had short-term complications, and 3/45 (6.7%) had shunt-related deaths. Medical management was discontinued in 15/40 and reduced in 9/40 of surviving dogs who had surgical attenuation. All medically managed, nonattenuated dogs (18/18) were maintained on their original shunt-related medication regimens. CONCLUSIONS: Clinical presentation of dogs ≥15 kg with extrahepatic portosystemic shunts was similar to the more commonly reported small breed dogs. Surgical management of single EHPSS in large dogs ≥15 kg had similar clinical short-term outcomes as small breed dogs. CLINICAL SIGNIFICANCE: Clinicians should be aware that large breed dogs with EHPSS share similar characteristics and clinical outcomes to small breed dogs. The significance of the presence of a hypoplastic portal vein warrants further research. Surgical treatment is a viable option for large breed dogs with EHPSS.

Case report: Clitoral adenocarcinoma in a mixed-breed female dog.

A 9-year-old, spayed female, mixed-breed dog was initially presented for evaluation of chronic dermatitis on the nasal planum, where a clitoral mass was discovered as an incidental finding during the exam. No further investigation of the clitoral mass was undertaken due to other significant dermal lesions and the lack of clinical significance of the mass at the time. However, ~1 month later, the dog was presented to the Emergency Service for bleeding from the vulva. The clitoral mass was found to have prolapsed; the mass was manually reduced back into a position within the vulvar folds and maintained with a purse-string suture. The dog was referred to the Theriogenology Service for further investigation and removal. On follow-up evaluation, the mass was noted to be multi-lobulated, ulcerated, cystic, and involving the clitoris but not the urethra. The urethra was easily catheterized, and no urinary abnormalities were found. No evidence of lymph node metastasis or hypercalcemia was noted prior to surgery. Ultrasonographic evaluation of the anal sacs was normal. The mass was removed, and histopathologic evaluation revealed a primary clitoral adenocarcinoma. On recheck evaluation, after 1 month, no evidence of metastasis or local recurrence was observed. Clitoral adenocarcinoma is a rarely reported neoplasm of the canine genital tract that shares many clinical, histopathological, and immunohistochemical features with canine apocrine gland anal sac adenocarcinoma. This case adds to the available knowledge on the condition, specifically regarding the frequency of complications such as hypercalcemia and metastasis, as previous reports suggest that these are present at least 50% of the time.

Histotripsy ablation for the treatment of feline injection site sarcomas: a first-in-cat in vivo feasibility study.

PURPOSE: Feline soft tissue sarcoma (STS) and injection site sarcoma (fISS) are rapidly growing tumors with low metastatic potential, but locally aggressive behavior. Histotripsy is a non-invasive focused ultrasound therapy using controlled acoustic cavitation to mechanically disintegrate tissue. In this study, we investigated the in vivo safety and feasibility of histotripsy to treat fISS using a custom 1 MHz transducer. MATERIALS AND METHODS: Three cats with naturally-occurring STS were treated with histotripsy before surgical removal of the tumor 3 to 6 days later. Gross and histological analyses were used to characterize the ablation efficacy of the treatment, and routine immunohistochemistry and batched cytokine analysis were used to investigate the acute immunological effects of histotripsy. RESULTS: Results showed that histotripsy ablation was achievable and well-tolerated in all three cats. Precise cavitation bubble clouds were generated in all patients, and hematoxylin & eosin stained tissues revealed ablative damage in targeted regions. Immunohistochemical results identified an increase in IBA-1 positive cells in treated tissues, and no significant changes in cytokine concentrations were identified post-treatment. CONCLUSIONS: Overall, the results of this study demonstrate the safety and feasibility of histotripsy to target and ablate superficial feline STS and fISS tumors and guide the clinical development of histotripsy devices for this application.

Characterizing the Ablative Effects of Histotripsy for Osteosarcoma: In Vivo Study in Dogs.

Osteosarcoma (OS) is a malignant bone tumor treated by limb amputation or limb salvage surgeries and chemotherapy. Histotripsy is a non-thermal, non-invasive focused ultrasound therapy using controlled acoustic cavitation to mechanically disintegrate tissue. Recent ex vivo and in vivo pilot studies have demonstrated the ability of histotripsy for ablating OS but were limited in scope. This study expands on these initial findings to more fully characterize the effects of histotripsy for bone tumors, particularly in tumors with different compositions. A prototype 500 kHz histotripsy system was used to treat ten dogs with suspected OS at an intermediate treatment dose of 1000 pulses per location. One day after histotripsy, treated tumors were resected via limb amputation, and radiologic and histopathologic analyses were conducted to determine the effects of histotripsy for each patient. The results of this study demonstrated that histotripsy ablation is safe and feasible in canine patients with spontaneous OS, while offering new insights into the characteristics of the achieved ablation zone. More extensive tissue destruction was observed after histotripsy compared to that in previous reports, and radiographic changes in tumor size and contrast uptake following histotripsy were reported for the first time. Overall, this study significantly expands our understanding of histotripsy bone tumor ablation and informs future studies for this application.

Sternohyoideus-sternothyroideus muscle flap to reconstruct oronasal fistulas due to maxillary cancer in four dogs.

OBJECTIVE: To describe the repair of oronasal fistulas in dogs treated for maxillary cancer, with a novel sternohyoideus-sternothyroideus muscle flap, and to report the outcome. ANIMALS: Client-owned dogs (n = 4) with oronasal fistulas related to cancer. STUDY DESIGN: Short case series. METHODS: Maxillary defects were caused by tissue destruction by the tumor and tumor response to radiation therapy in two cases and a complication of caudal maxillectomy in two cases, one of which had neoadjuvant radiation therapy. All tumors were >4 cm at the level of the maxilla. Flaps were harvested by transecting the ipsilateral sternothyroideus and sternohyoideus muscles from their origin at the manubrium and costal cartilage. The muscles were rotated around the base of the cranial thyroid artery and tunneled subcutaneously in the neck and through an incision in the caudodorsal aspect of the oral cavity. The muscle flap was sutured to the edges of the oronasal fistula. RESULTS: The flap reached as far rostral as the level of the first premolar without tension. All dogs had clinical signs that improved postoperatively. All dogs had partial dehiscence of the flap. CONCLUSION: This flap was associated with a high rate of complications; however, all flaps were used in challenging cases. Clinical signs related to oronasal fistula were improved in all dogs in this case series.

Retroperitoneal myxosarcoma in a cat.

This report details a retroperitoneal myxosarcoma in a cat that exhibited extremely aggressive biological behavior. An exploratory midline celiotomy revealed a left-sided retroperitoneal mass firmly adhered to the hypaxial musculature. Histopathological evaluation identified the mass as a myxosarcoma. Following surgical excision, the mass rapidly recurred within 6 weeks after surgery.

Histotripsy Ablation of Spontaneously Occurring Canine Bone Tumors In Vivo.

OBJECTIVE: Osteosarcoma (OS) is a devastating primary bone tumor in dogs and humans with limited non-surgical treatment options. As the first completely non-invasive and non-thermal ablation technique, histotripsy has the potential to significantly improve the standard of care for patients with primary bone tumors. INTRODUCTION: Standard of care treatment for primary appendicular OS involves surgical resection via either limb amputation or limb-salvage surgery for suitable candidates. Biological similarities between canine and human OS make the dog an informative comparative oncology research model to advance treatment options for primary OS. Evaluating histotripsy for ablating spontaneous canine primary OS will build a foundation upon which histotripsy can be translated clinically into a standard of care therapy for canine and human OS. METHODS: Five dogs with suspected spontaneous OS were treated with a 500 kHz histotripsy system guided by real-time ultrasound image guidance. Spherical ablation volumes within each tumor (1.25-3 cm in diameter) were treated with single cycle histotripsy pulses applied at a pulse repetition frequency of 500 Hz and a dose of 500 pulses/point. RESULTS: Tumor ablation was successfully identified grossly and histologically within the targeted treatment regions of all subjects. Histotripsy treatments were well-tolerated amongst all patients with no significant clinical adverse effects. Conclusion & Significance: Histotripsy safely and effectively ablated the targeted treatment volumes in all subjects, demonstrating its potential to serve as a non-invasive treatment modality for primary bone tumors.

Long-term postoperative effects of administration of allogeneic blood products in 104 dogs with hemangiosarcoma.

OBJECTIVE: To determine the influence of administering allogeneic blood products (ABP) on the progression of hemangiosarcoma in dogs. STUDY DESIGN: Multi-institutional, retrospective study. SAMPLE POPULATION: One hundred four dogs with hemangiosarcoma that survived until postoperative discharge from the hospital. METHODS: Medical records of dogs that had been operated on for hemoangiosarcoma were reviewed for signalment, presence of a hemoabdomen, presence of metastatic disease, and whether the dog had received chemotherapy or Yunnan Baiyao. Data that were collected were compared between dogs that received perioperative ABP and those that did not. Disease-free interval was compared between groups. The Kaplan-Meier method was used to obtain univariate descriptive statistics for time to clinical decline. A multivariable Cox regression model was used to analyze association or effect of potential predictor variables. RESULTS: The median disease-free interval (DFI) was shorter in the 67 dogs that received a blood transfusion (76 days; range, 1-836) than in the 37 dogs that did not receive a blood transfusion (120 days; range, 38-916). According to the multivariable Cox regression model, administration of blood products (P = .04) and the presence of gross metastatic disease at the time of surgery (P < .01) shortened the DFI, whereas administration of Yunnan Baiyao (P = .01) prolonged the DFI. CONCLUSION: Allogeneic blood product administration was associated with a shorter disease-free interval in this population. However, we could not demonstrate the association between blood products and shorter DFI because of confounding factors. CLINICAL SIGNIFICANCE: Dogs that receive ABP at the time of surgical therapy for hemangiosarcoma may have accelerated disease progression compared with dogs that do not receive ABP.

Removal of hemangiosarcoma cells from canine blood with a cell salvage system and leukocyte reduction filter.

OBJECTIVE: To determine the ability of an intraoperative cell salvage (IOCS) system and a leukocyte reduction filter (LRF) to remove hemangiosarcoma (HSA) cells from canine blood. STUDY DESIGN: Cultured HSA cells were added to canine blood to simulate intraoperative hemorrhage and address hemoabdomen from ruptured splenic HSA. The blood/HSA cell mixture was processed through an IOCS, followed by LRF processing. SAMPLE POPULATION: Whole blood from 3 healthy dogs combined with cultured HSA cells. METHODS: The ability of quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), multiparameter flow cytometry, and cytologic examination to detect 50 HSA cells per milliliter of culture media was confirmed. RT-PCR, multiparameter flow cytometry, and cytologic examination were used to determine the presence of cultured HSA cells at 4 points during processing. RESULTS: HSA cells were found in all control samples and in all samples after IOCS but prior to LRF processing with all 3 cell detection methods. HSA cells were not found after IOCS/LRF processing with all 3 cell detection methods. CONCLUSION: IOCS combined with LRF processing is able to remove cultured HSA cells from canine blood. The addition of LRF to IOCS may allow application of IOCS in dogs with HSA. CLINICAL SIGNIFICANCE: A combination of IOCS and LRF processing may provide an alternative to allogeneic blood transfusion in dogs with hemoabdomen due to HSA.