Laparoscopic liver lobectomy in a cat

Abstract

Case summary

A 7-year-old neutered male domestic shorthair cat was presented for evaluation of a large intra-abdominal mass. Contrast-enhanced CT revealed a pedunculated hepatic mass measuring 15 × 9.5 × 6.5 cm arising from the papillary process of the caudate lobe, without evidence of metastasis. A three-port laparoscopic liver lobectomy was performed. The mass, attached by a torsed pedicle, was excised using a bipolar advanced energy vessel sealing device (ENSEAL; Ethicon). Histopathology confirmed a primary hepatic fibrosarcoma with complete resection. The cat recovered uneventfully, was discharged the following day and received five cycles of adjuvant doxorubicin (Adriamycin; Pfizer), maintaining an excellent quality of life and stable disease for at least 3 years.

Relevance and novel information

This is the first report of laparoscopic liver lobectomy in a cat with a large torsed hepatic mass. The case demonstrates that minimally invasive liver lobectomy can be successfully performed in feline patients, even in challenging cases involving substantial or torsed lobes.

Plain language summary

Removing a part of a cat liver using a minimally invasive surgery

A 7-year-old male cat was found to have a large growth on his liver. Scans showed that the growth was attached by a twisted stalk, but there was no sign that it had spread elsewhere. The cat underwent a minimally invasive surgery, called a laparoscopic liver lobectomy, to remove the affected part of the liver. The growth was successfully removed, and laboratory testing confirmed it was a type of liver tumour called fibrosarcoma. The cat recovered very well from surgery and went home the next day. He also received additional chemotherapy to reduce the chance of the tumour coming back. Three years after the surgery, the cat remained healthy, happy and showed no signs of disease. This case is important because it is the first report of minimally invasive liver surgery being used in a cat with a large, twisted liver tumour. It shows that even complex liver problems in cats can be treated safely with less invasive techniques, which can help cats recover faster and maintain a good quality of life.

Introduction

Feline hepatic masses present a diagnostic and therapeutic challenge. Differential diagnoses include hepatocellular carcinoma, biliary carcinoma, sarcoma, benign neoplasia and lymphoma. Primary hepatic sarcomas are rare and carry a poor prognosis because of aggressive behaviour and metastatic potential. ¹ The most common hepatic sarcomas are haemangiosarcomas. ¹ Surgical excision remains the treatment of choice for solitary masses, although outcomes remain guarded. ² Many tumours are biologically aggressive,^1,3,4 and surgery carries risks of haemorrhage and complications related to complex hepatic anatomy.^5,6

In veterinary medicine, liver lobectomy in cats is typically performed via open celiotomy. Laparoscopic liver lobectomy has been described in canine cadaveric studies and six clinical cases in dogs, ⁷ mainly for left and central divisions in dogs weighing up to 15 kg with masses smaller than 5 cm. More recently, a strict laparoscopic left liver lobectomy has been reported in a clinical canine patient with a large liver mass (9.4 × 7.1 × 4.9 cm). The mass was mechanically fragmented and removed through a small incision. ⁸ In cats, laparoscopic hepatobiliary procedures have included liver biopsies,^{9 –13} cyst excision, ¹⁴ portosystemic shunt attenuation^15,16 and cholecystectomy. ¹⁷ Laparoscopic liver lobectomy is infrequently reported, likely due to the technical challenges of safely mobilising and resecting liver tissue, the risk of haemorrhage, limited experience and the small size of feline patients, which can make laparoscopic instrumentation more difficult. Nevertheless, the potential benefits of laparoscopy include improved visualisation, reduced tissue trauma, less postoperative pain and faster recovery.^13,18

This report describes the first laparoscopic liver lobectomy in a cat with a large torsed hepatic mass, demonstrating the feasibility of minimally invasive approaches for feline hepatic surgery.

Case description

A 7-year-old neutered male domestic shorthair cat was referred for evaluation of an intra-abdominal mass identified incidentally by the owner. The cat had no clinical signs apart from a distended abdomen. Abdominal ultrasonography and fine-needle aspiration performed by the referring veterinarian had failed to determine the origin of the mass.

On presentation, the cat was bright, alert and haemodynamically stable. Abdominal palpation revealed a large, firm mass. Haematology and serum biochemistry showed mild non-regenerative anaemia (haematocrit 28%). Liver-associated parameters, including alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase and total bilirubin, were within reference intervals (RIs).

Contrast-enhanced CT, performed under general anaesthesia, revealed a 15 × 9.5 × 6.5 cm pedunculated mass arising from the papillary process of the caudate liver lobe with subtle mineralisation (Figure 1). No imaging evidence of liver torsion was apparent at the time of CT. A full thoracic study showed no evidence of pulmonary metastatic disease. Mild sternal lymphadenopathy and mild splenic enlargement were also noted. Differential diagnoses included hepatocellular carcinoma, biliary carcinoma, sarcoma, benign hepatic neoplasia and lymphoma.

Figure 1

CT scan showing a contrast-enhancing pedunculated liver mass measuring 15 × 9.5 × 6.5 cm arising from the papillary process of the caudate lobe, with subtle mineralisation (white arrows)

General anaesthesia was induced after premedication with methadone (0.15 mg/kg IV) and dexmedetomidine (0.0025 mg/kg IV), using propofol for induction and isoflurane for maintenance. Bilateral quadratus lumborum blocks were performed with bupivacaine 0.25% (3.5 ml per side) to provide perioperative analgesia.

The cat was positioned in dorsal recumbency, and a three-port laparoscopic approach was performed (Figure 2). A 5 mm camera port was placed 2 cm caudal to the umbilicus on the midline. Two 5 mm working ports were positioned under direct visualisation: one in the right cranial abdomen approximately 4 cm lateral to the midline and just caudal to the costal margin, and the other in the left cranial abdomen approximately 3 cm caudal to the left costal arch and 3 cm lateral to the midline. Intraoperative examination revealed a pedunculated hepatic mass attached to the caudate lobe by a torsed pedicle (Figure 3). The affected lobe was resected using a bipolar advanced energy vessel-sealing device (ENSEAL; Ethicon), achieving complete haemostasis (Figure 4). The specimen was retrieved through the midline camera port using a medium Alexis O wound protector/retractor (Applied Medical) via an incision of approximately 9 cm. All port sites were closed routinely.

Figure 2

Three-port laparoscopic approach: a 5 mm camera port placed 2 cm caudal to the umbilicus on the midline. Two 5 mm working ports: one in the right cranial abdomen approximately 4 cm lateral to the midline and just caudal to the costal margin, and the other in the left cranial abdomen approximately 3 cm caudal to the left costal arch and 3 cm lateral to the midline

Figure 3

Laparoscopic view of the hepatic mass and its torsed pedicle

Figure 4

Laparoscopic resection of a hepatic lobe using an ENSEAL vessel-sealing device

Recovery from anaesthesia was uneventful. The cat was discharged the following day with meloxicam (0.05 mg/kg PO q24h) prescribed for 5 days for postoperative analgesia.

Histopathological examination confirmed a completely excised primary hepatic fibrosarcoma with clear surgical margins. The cat subsequently received five cycles of doxorubicin (1 mg/kg IV every 3 weeks). Haematology was performed before each treatment and remained within RIs.

At 13 weeks postoperatively, the cat remained clinically well with no evidence of disease progression and an excellent quality of life. Postoperative imaging was declined by the owner, limiting objective assessment of disease control. At 3 years postoperatively, the owner was contacted for follow-up evaluation and reported that the cat continued to have a good quality of life.

Discussion

Primary hepatic sarcomas are rare, comprising 1–2.9% of feline tumours, ¹⁹ with mesenchymal tumours accounting for 15% of non-haematopoietic malignant liver tumours. ¹ In dogs, primary hepatic sarcomas represent 0.6–1.5% of neoplasms.^3,20

Hepatic torsion is rare in cats. Proposed mechanisms include abnormal hepatic ligaments, congenital anomalies (diaphragmatic hernia, pectus excavatum), trauma, sudden movement or mass effect from neoplasia.^{21 –23} Many cases have no underlying neoplasm. ²³ In this case, the size of the mass and its torsion may have facilitated mobilisation and excision but also posed vascular risks.

Laparoscopic liver lobectomy in veterinary medicine remains limited. Michael et al ⁷ reported a cadaveric study and six clinical canine cases, concluding that laparoscopic liver lobectomy using an endoscopic stapler was feasible in cadavers weighing up to 15 kg, with one dog in the clinical series requiring conversion to an open approach. In this feline case, a 15 cm mass was successfully excised laparoscopically; however, the midline incision had to be extended to 9 cm for specimen retrieval. This illustrates that removal of very large masses can partially offset the typical advantages of minimally invasive surgery, such as smaller incisions and reduced postoperative trauma. Techniques such as laparoscopic morcellation, in which a large mass is fragmented within a containment bag for removal through a smaller incision, or laparoscopic-assisted microwave ablation, which can reduce tumour size or ablate lesions before excision, may help preserve the benefits of minimally invasive approaches in future cases.

Laparoscopic surgery offers other advantages, including reduced postoperative pain, decreased wound complications and shorter hospitalisation.^{18,24 –27} Instrumentation is critical in hepatic surgery. Although stapling devices can reduce complications by up to 19-fold in open celiotomy, ²⁸ vessel-sealing devices can provide safe and effective haemostasis during liver lobectomy when staplers are not feasible. In cats, thoracoabdominal staplers have successfully removed hepatic lesions; ⁵ however, in this case, an endoscopic gastrointestinal anastomosis (Endo GIA) stapler was not used because of the small area of pedunculated liver tissue of the mass. ⁷ The bipolar advanced energy vessel-sealing device (ENSEAL; Ethicon) allowed complete resection and haemostasis without intraoperative bleeding, demonstrating its utility as an alternative to staplers in selected cases.

A key limitation of this case is the absence of postoperative imaging to confirm long-term recurrence status. Future research should focus on (1) prospective evaluation of laparoscopic liver lobectomy in cats, considering tumour size, lobe location and patient size, (2) oncologic outcomes compared with open celiotomy and (3) torsion-specific cases to assess technical advantages or risks.

Conclusions

This case illustrates that laparoscopic liver lobectomy can be safely performed in cats, including for large, pedunculated and torsed hepatic masses. Minimally invasive techniques offer clinical benefits such as rapid recovery, reduced postoperative pain and maintenance of quality of life. Careful patient selection, attention to abdominal workspace and appropriate instrumentation are essential. Further studies are warranted to define long-term outcomes and refine surgical protocols in feline hepatobiliary surgery.