CASE REPORT RAPPORT DE CAS
Stefano Nicoli, Alessia Vitali, Diego Iannelli, Ludovica Biassoni, Cyndi Mangano, Nicola Iannelli
Kidney sparing during surgical treatment of an adrenocortical carcinoma with renal vein invasion in a cat
ABSTRACT
A 15-year-old domestic shorthair cat was presented with gastrointestinal signs, polyuria, polydipsia, and weakness. Abdominal bruit (“whooshing” sound from turbulent blood flow) and hypertension (systolic blood pressure: 200 mmHg) were present. A left adrenal gland mass was detected with abdominal ultrasonography; a subsequent CT examination identified a mass and a thrombus in the ipsilateral renal vein. Adrenalectomy and venotomy were completed but nephrectomy was not necessary. Histological diagnosis was an adrenocortical carcinoma. There were no clinical signs at a follow-up examination 30 mo after surgery.
Key clinical message:
This report describes successful surgical management of feline adrenocortical carcinoma with renal vein invasion without kidney damage. This case suggests that, after correct diagnosis and in well-selected cases, surgery to remove adrenal tumors and thrombi in cats, despite renal vein invasion, can be done with excellent short- and long-term outcomes.
RÉSUMÉ
Sauvegarde des reins lors du traitement chirurgical d’un carcinome corticosurrénalien avec invasion des veines rénales chez un chat
Un chat domestique à poil court de 15 ans a été présenté avec des signes gastro-intestinaux, une polyurie, une polydipsie et une faiblesse. Des bruits abdominaux (« sifflement » provenant d’un flux sanguin turbulent) et une hypertension (pression artérielle systolique : 200 mmHg) étaient présents. Une masse de la glande surrénale gauche a été détectée à l’échographie abdominale; un examen tomodensitométrique ultérieur a identifié une masse et un thrombus dans la veine rénale ipsilatérale. La surrénalectomie et la veinotomie ont été réalisées mais la néphrectomie n’a pas été nécessaire. Le diagnostic histologique était un carcinome corticosurrénalien. Il n’y avait aucun signe clinique lors d’un examen de suivi 30 mois après l’intervention chirurgicale.
Message clinique clé :
Ce rapport décrit la prise en charge chirurgicale réussie du carcinome corticosurrénalien félin avec invasion des veines rénales sans lésion rénale. Ce cas suggère qu’après un diagnostic correct et dans des cas bien sélectionnés, une intervention chirurgicale visant à éliminer les tumeurs surrénales et les thrombi chez les chats, malgré l’invasion des veines rénales, peut être réalisée avec d’excellents résultats à court et à long terme.
Can Vet J 2024;65:894-899
(Traduit par D’ Serge Messier)
A drenal tumors are infrequent findings in cats, representing about 0.2% of all feline neoplasms, compared to 1 to 2% of all spontaneous canine neoplasms (1-4). Adrenal tumors are classified as either cortical tumors (adenoma or adenocarcinoma) or medul- lary tumors (pheochromocytoma). Cortical tumors can be functional, producing excessive adrenocortical hormones (cortisol, aldosterone, or sex hormones, alone or in combi- nation) and resulting in a clinical syndrome, or they may be nonfunctional.
Primary hyperaldosteronism is a rare condition in cats. Hypersecretion of mineralocorticoids can be caused by bilateral hyperplasia of the zona glomerulosa of the adre- nal cortex or, in rare cases, by an aldosterone-secreting tumor, defined as an aldosteronoma (5-7). This neoplasia is often associated with an expansive lesion, which may be accompanied by invasion of a neoplastic thrombus in the caudal vena cava, phrenicoabdominal vein, or, rarely, renal vein (4,8). Cats and dogs with adrenal gland neoplasia can undergo medical treatment to reduce clinical signs, but surgical treatment is preferred for this lesion and for any associated tumor thrombi. However, there are conflicting data regarding whether vascular invasion worsens short- term prognosis (2,8-12).
When small thrombi invade the phrenicoabdominal vein, they can be managed and removed concurrently with the vessel and tumor, though removal of more extended thrombi that enter the caudal vena cava usually require a caval venotomy (1,11,13). In rare cases with direct invasion of the renal vein from tumor thrombi, nephrectomy has been performed. In some studies, concurrent nephrectomy and adrenalectomy had a poor prognosis, with increased risk of renal failure and shorter survival (1,11,13). In a recent, noteworthy study of 5 dogs that had adrenal tumors with tumor thrombi present in the renal vein, nephrectomy was avoided by renal venotomy. These surgical treatments enabled kidney sparing and may have reduced morbidity associated with the procedure (14).
To our knowledge, this is the first report of adrenocorti- cal carcinoma with invasion of the renal vein in a cat, with a syndrome of hyperaldosteronism treated with renal vein venotomy and thrombectomy without kidney damage.
CASE DESCRIPTION
A 15-year-old castrated male domestic shorthair cat weigh- ing 5 kg was presented to the Clinica Veterinaria Camagna (Reggio Calabria, Italy) with a history of intermittent diar- rhea, weakness, polyuria, and polydipsia.
Physical examination revealed abdominal bruit (“whooshing” sound from turbulent blood flow) and hyper- tension (systolic blood pressure: 200 mmHg). The remain- ing findings of the clinical evaluation were unremarkable. Further investigation was completed under sedation and included hematology, biochemistry, urinalysis, echocar- diography, and abdominal ultrasound.
Hematology results were normal. For biochemistry and urinalysis, abnormal findings included hypokalemia [3.3 mmol/L; reference interval (RI): 3.5 to 5.8 mmol/L], hypernatremia (163 mmol/L; RI: 144 to160 mmol/L), and urine specific gravity (USG) of 1.020.
Echocardiography findings were normal. Abdominal ultrasound revealed the presence of a structure of at least 1.5 cm in diameter on the left adrenal gland that was sub- jected to fine-needle aspiration. Cytological examination revealed a cell population compatible with adrenal neo- plasia of cortical origin. All other structures, including the right adrenal gland, were normal.
The cat was returned 2 d later. An endocrinology panel detected an increased aldosterone concentration (930.5 ng/ml; RI: 11.3 to 294.3 ng/ml), though baseline cortisol concentration and concentrations after ACTH stim- ulation were normal. Contrast computed tomography (CT) identified a circular structure at least 1.3 cm in diameter on the left adrenal caudal pole; the ipsilateral renal vein was dilated and invaded by a thrombus (Figure 1). However, all other abdominal organs appeared normal and there was no evidence of pulmonary metastasis.
Adrenalectomy was considered the treatment of choice. The owner was advised about surgical risks, particularly regarding renal vein invasion. After discussion with the owner and in accordance with their wishes, the surgical plan was to perform left adrenalectomy and try to spare the left kidney by attempting to remove the thrombus via venotomy.
Based on the anesthesiology examination, the cat was classified in the 4th class as defined by the American Society of Anesthesiologists. The cat was sedated (tiletamine- zolazepam, 0.1 mg/kg, IV), induced with propofol (1 mL/kg, IV), intubated, and maintained under anesthesia with sevo- flurane, with continuous monitoring during surgery.
The hair was clipped in the abdominal area, the cat was placed in dorsal recumbency, a routine presurgical scrub was done, and a cranial midline celiotomy was made. The left adrenal gland was identified, and the tumor was iso- lated from blood vessels and from numerous adhesions with cotton swabs and HarmonicWave (Ultracision; Johnson &
A
B
C
Johnson, New Brunswick, New Jersey, USA), with care to avoid damage to the cranial mesenteric artery and caudal vena cava. A Satinsky vascular clamp was placed on the renal vein (Figure 2 A) to reduce the renal vein inflow and isolate the thrombus. A longitudinal venotomy (~5 mm) was made, and the thrombus was grasped with a DeBakey clamp and carefully removed by constant traction. The venotomy was then closed with a simple continuous suture of Prolene 7-0 (Ethicon) (Figure 2 B) and the vascular clamp removed. The venotomy was checked for residual hemorrhage. After lavage of the peritoneal cavity with
sterile warm saline, the celiotomy was closed routinely. Recovery from anesthesia was uneventful, and the cat was discharged after 2 d of hospitalization. During hospitaliza- tion, the cat was given fluid therapy (NaCl, 10 mL/h, IV) and meloxicam (0.05 mg/kg, PO, q24h).
At follow-up examinations (at 24 h and at 7, 10, and 30 d after surgery), the cat was doing clinically well and renal functions were within normal ranges (Table 1). Histological analysis confirmed the diagnosis of adrenocortical car- cinoma. There was a multinodular, infiltrating structure composed of nests and trabeculae of polygonal cells,
A
B
| Preoperative | 24 h postoperative | 7 d postoperative | 10 d postoperative | 30 d postoperative | |
|---|---|---|---|---|---|
| Creatine, mg/dL (RI: 0.6 to 1.6 mg/dL) | 1.7 | 1.5 | 1.2 | 1.2 | 1.3 |
| Blood urea nitrogen, mg/dL (RI: 27 to 75 mg/dL) | 30 | 35 | 50 | 55 | 35 |
| Sodium, mmol/L (RI: 144 to 160 mmol/L) | 163 | 132 | 133 | 132.5 | 130 |
| Chloride, mmol/L (RI: 110 to 125 mmol/L) | 95.4 | 95.4 | 95.4 | 93 | 97 |
| Potassium, mmol/L (RI: 3.5 to 5.5 mmol/L) | 2.5 | 4.07 | 4.08 | 4.06 | 4 |
| Glucose, mg/dL (RI: 80 to 120 mg/dL) | 90 | 89 | 100 | 120 | 100 |
RI - Reference interval.
separated by a delicate fibrovascular stroma. Anisocytosis and anisokaryosis were moderate, and mitotic figures were occasional.
At a 20-month follow-up, physical examination and hematology, biochemistry, urinalysis, and ultrasound examinations were all normal. At a 30-month follow-up, physical examination and hematology were normal. There was a moderate increase in serum creatinine (2.7 mg/dL; RI: 0.8 to 2.4 mg/dL). Urinary specific gravity remained within normal limits (USG: 1.028). Ultrasonographically, both kidneys appeared normal, with no signs suggestive of left renal vein thrombosis.
DISCUSSION
We describe here preservation of the kidney during success- ful surgical management of feline adrenocortical carcinoma with invasion of the renal vein, with excellent short- and long-term outcomes.
Although adrenal neoplasia is infrequent in cats, there are some reports (3-5). However, to the best of our knowl- edge, this is the first report of an adrenal tumor with
renal vein invasion in a cat surgically treated without nephrectomy.
Diagnostic imaging, particularly ultrasonography, was the first step to visualize the lesion. Adrenal size and asymmetry may help in confirming suspicion of endocrine diseases in cats, though ultrasonographic appearance of adrenal glands cannot be used to differentiate benign versus malignant lesions (15).
The CT examination identified a circular structure at least 1.3 cm in diameter on the left adrenal caudal pole, with the ipsilateral renal vein dilated and invaded by a thrombus. In patients with adrenal disease, the use of CT is important in determining adrenal gland size; identifying the relationship of the tumor with surrounding tissues, vessels, and organs; detecting the presence and size of a thrombus; issuing an oncologic grading; optimizing planning of the surgical approach and technique; and issuing a prognosis.
Hyperaldosteronism was marked in this cat. Cases of pri- mary hyperaldosteronism are not rare in the literature and must be considered as a differential diagnosis in middle- aged and older cats with hypokalemic polymyopathy and/or
systemic hypertension (8). Primary hyperaldosteronism was diagnosed in a 13-year-old cat with an adrenal corti- cal carcinoma. Adrenalectomy resolved the hypokalemia, hypertension, and other electrolyte abnormalities. Surgical excision of a tumor thrombus from the caudal vena cava was accomplished without pathological narrowing of the vena cava (9).
In the current case, surgery was our preferred approach. Surgical treatment for feline adrenal tumors (regardless of tumor type) is associated with good long-term survival, with preoperative adrenal generally recommended (4). Acute adrenal hemorrhage can occur as a consequence of tumor necrosis and rupture and can cause severe hypovolemia and anemia in cats with primary hyperaldosteronism (8,16,17). Caval thrombi associated with adrenal gland tumors are amenable to adrenalectomy and thrombectomy without sig- nificantly increased perioperative morbidity and mortality rates, assuming the surgeon is experienced in appropriate techniques (11).
Tumor thrombectomy is traditionally done in dogs with invasive adrenal tumors. This treatment is achieved through caudal vena cava or phrenicoabdominal venotomy; how- ever, when the thrombi involve the renal vein, or if there is neoplastic infiltration of the renal parenchyma, ipsilateral nephrectomy may be done concurrently with adrenalec- tomy. Nephrectomy was done in 17 to 26% of cases in dogs with invasive adrenal tumors (1,10,12). Whereas these neoplasms are rare in humans, renal vein thrombosis was described in 9 to 19% of patients (18).
It is well-established that nephrectomy is associated with worse short- and long-term prognoses in dogs undergoing this surgical treatment (10). In a recent study (14), Chiti et al carried out adrenalectomy and renal vein thrombec- tomy on 5 dogs with invasive adrenal tumors. This enabled preservation of the kidney, obviated the requirement for nephrectomy, and potentially reduced surgical morbid- ity. Furthermore, this technique was associated with good short- and long-term outcomes.
The surgical technique described in this case report allowed us to successfully remove the adrenal tumor and renal vein thrombus through venotomy without nephrec- tomy. Renal venotomy in cats is technically demanding due to the small diameter of the renal vein compared to the vena cava and the delicate nature of the vessel. Potential complications can be caused by vessel wall damage and occlusion of renal vein inflow. Vascular and adrenal surgi- cal experience is considered important for achieving good results.
In cases with an adrenocortical tumor, clinicians should investigate whether the tumor produces excessive blood concentrations of glucocorticoids, mineralocorti- coids, sex steroids, or combinations of these hormones. Hypersecretion of > 1 adrenal hormone may occur in a cat with an adrenocortical tumor (5,19).
In conclusion, this clinical case confirmed in a cat what has been reported in the dog. Although the renal vein is narrower in the cat, it is possible to perform adrenalec- tomy with removal of a thrombus in the renal vein, thereby preserving kidney function and avoiding poorer outcomes associated with the nephroureterectomy procedure concur- rent with adrenalectomy.
ACKNOWLEDGMENTS
The authors thank all staff of the Clinica Veterinaria Camagna for providing this clinical case. CVJ
REFERENCES
1. Schwartz P, Kovak JR, Koporowski A, Ludwig LL, Monette S, Bergman PJ. Evaluation of prognostic factors in the surgical treatment of adrenal gland tumors in dogs: 41 cases. J Am Vet Med Assoc 2008;232:77-84.
2. Lang JM, Schertel E, Kennedy S, et al. Elective and emer- gency surgical management of adrenal gland tumors: 60 cases (1999-2006). J Am Anim Hosp Assoc 2011;47:428-435.
3. Lunn KF, Page RL. Tumor of the endocrine system. In: Withrow SJ, Vail DM, eds. Withrow and MacEwen’s Small Animal Clinical Oncology. 5th ed. St. Louis, Missouri. Saunders Elsevier, 2013:504-531.
4. Daniel G, Mahony OW, Markivich JE, et al. Clinical find- ings, diagnosis and outcome in 33 cats with adrenal neopla- sia (2002-2013). J Feline Med Surg 2016;18:77-84.
5. Attipa C, Beck S, Lipscomb V, et al. Aldosterone-producing adrenocortical carcinoma with myxoid differentiation in a cat. Vet Clin Pathol 2018;47:660-664.
6. Rijnberk A, Voorhout G, Kooistra HS, et al. Endocrinology: Hyperaldosteronism in a cat with metastasized adrenocortical tumor. Vet Q 2001;23:38-43.
7. Del Magno S, Pisoni L, Magarotto J, et al. Due casi di sospetto iperaldosteronismo primario nel gatto [Two cases of sus- pected primary hyperaldosteronism in cats] [article in Italian]. Veterinaria 2012;26:41-50.
8. Lo AJ, Holt DE, Brown DC, et al. Treatment of aldosterone secreting adrenocortical tumors in cats by unilateral adre- nalectomy: 10 cases (2002-2012). J Vet Intern Med 2014; 28:137-143.
9. Rose SA, Kyles AE, Labelle P, et al. Adrenalectomy and caval thrombectomy in a cat with primary hyperaldosteronism. J Am Anim Hosp Assoc 2007;43:209-214.
10. Piegols HJ, Brittany EA, Lapsley JM, et al. Risk factors influ- encing death prior to discharge in 302 dogs undergoing uni- lateral adrenalectomy for treatment of primary adrenal gland tumors. Vet Comp Oncol 2023;21:673-684.
11. Kyles AE, Feldman EC, De Cock HE, et al. Surgical management of adrenal gland tumors with and without associated tumor thrombi in dogs: 40 cases (1994-2001). J Am Vet Med Assoc 2003;223:654-662.
12. Barrera JS, Bernard F, Ehrhart EJ, Withrow SJ, Monnet E. Evaluation of risk factors for outcome associated with adrenal
gland tumors with or without invasion of the caudal vena cava and treated via adrenalectomy in dogs: 86 cases (1993-2009). J Am Vet Med Assoc 2013;242:1715-1721.
13. Mayhew PD, Boston SE, Zwingenberger AL, et al. Perioperative morbidity and mortality in dogs with invasive adrenal neo- plasms treated by adrenalectomy and cavotomy. Vet Surg 2019; 48:742-750.
14. Chiti LE, Mayhew PD, Massari F. Renal venotomy for throm- bectomy and kidney preservation in dogs with adrenal tumors and renal vein invasion. Vet Surg 2021;50:872-879.
15. Combes A, Pey P, Paepe D, et al. Ultrasonographic appearance of adrenal glands in healthy and sick cats. J Feline Med Surg 2013;15:445-457.
16. Kirkwood N, Boland L, Brunel L, Wardman A, Barrs VR. Acute adrenal haemorrhage in two cats with aldosterone- secreting adenocarcinomas. JFMS Open Rep 2019;5: 2055116919840828.
17. Mitchell JW, Mayhew PD, Culp TNW, et al. Outcome of lapa- roscopic adrenalectomy for resection of unilateral noninvasive adrenocortical tumors in 11 cats. Vet Surg 2017;46:714-721.
18. Pérez Utrilla M, Nunez Mora C, Rojo Sebastian A, Cabrera Castillo PM, Garcìa Mediero JM. Surgical approach to a large left adrenocortical mass with associated tumor thrombosis of the left renal vein: Preservation of the ipsilateral kidney. Adv Urol 2009;8:365-805.
19. Syme HM, Scott-Moncrieff JC, Treadwell NG, et al. Hyperadre- nocorticism associated with excessive sex hormone production by an adrenocortical tumor in two dogs. J Am Vet Med Assoc 2001;219:1725-1728.