Ultrasonographic diagnosis of an adrenocortical carcinoma in a dog
F. Liste, M. Cuevas, M. Gascon, J. Garcia de Jalon, I. Cuevas
Veterinary Record (1997) 140, 339-341
The ultrasonographic findings in a nine-year-old female Drahthaar with an adrenocortical carcinoma of the left adrenal gland are described. Examination of the abdomen revealed a large, hypoechoic mass cranial to the left kidney. Areas of calcification inside the mass and the lateral displace- ment of the caudal vena cava were assessed. The right adrenal gland was thinner and smaller than normal. Several target- like lesions were present in the hepatic parenchyma. A moder- ate amount of haemorrhagic abdominal fluid was also present. The ultrasonographic findings were consistent with this type of adrenal neoplasia which produces atrophy of the contra- lateral gland and frequently metastasises to the liver. The ultrasonographic diagnosis of adrenocortical carcinoma was confirmed by histopathological examination.
THE diagnosis of adrenal neoplasia in dogs is difficult. Pheochromocytomas often result in non-specific signs of cardio- vascular failure such as dyspnoea or panting, and most adrenocor- tical tumours are non-functional and the clinical signs are related to distant metastases (Capen 1978, Bouayad and others 1987). Diagnostic tests are frequently used in the detection of adrenal disorders. Low or high dose dexamethasone suppression tests, the measurement of endogenous plasma adrenocorticotrophic hor- mone (ACTH), urinary cortisol:creatinine ratio or the ACTH stimula- tion test are useful in the detection of canine hyperadrenocorti- cism. However, the condition may be due to an adrenocortical tumour or be pituitary-dependent. For example, when there is no suppression after both dexamethasone suppression tests hyper- adrenocorticism is confirmed but the cause of the condition remains unknown. Furthermore, the urinary cortisol:creatinine ratio is not a reliable test when renal disease is present (Feldman 1983, Reusch and Feldman 1991, Widmer and Guptill 1995). Several diagnostic imaging methods have been used in the assess- ment of the canine adrenal glands. However, survey radiography lacks sensitivity in the detection of adrenal disorders (Penninck and others 1988). Other diagnostic imaging procedures such as computed x-ray tomography and magnetic resonance imaging have been proposed in the assessment of canine adrenal and pitu- itary glands (Voorhout 1990, Voorhout and others 1990, Bertoy and others 1995, Widmer and Guptill 1995), but they are expen- sive and not readily available for veterinary use. On the other hand, adrenal gland ultrasonography is a well established imaging mode in human medicine. In small animal practice, the small size of the adrenal gland, and its location and complex shape, make imaging difficult. However, the sonographic appearance of the canine adrenal glands has recently been described by several authors (Schelling 1991, Grooters and others 1994, 1995, Barthez and others 1995). Adrenal ultrasonography has proved to be an important diagnostic tool in the detection of pituitary-dependent hyperadrenocorticism and adrenal neoplasia in the dog (Kantrowitz and others 1986, Bouayad and others 1987, Poffenbarger and others 1988, Schelling 1991, Widmer and
Guptill 1995) because the adrenal glands have different ultrasono- graphic features in the two disorders. An ultrasonographic exami- nation of the adrenal glands is a non-invasive and useful method for detecting adrenal masses, as well as small variations in adrenal size or shape (Barthez and others 1995, Grooters and others 1995). The present case report describes the ultrasonographic findings in a dog with an adrenocortical carcinoma in the left adrenal gland.
Case history
A nine-year-old spayed female Drahthaar weighing 27 kg had a history of depression, polyuria and anorexia. Its abdomen was very distended. The dog was lethargic and had no signs of skin lesions. Routine haematological and biochemical examinations of peripheral blood revealed a mild regenerative anaemia (4.93 x 1012/litre, normal range 5.4 to 8.3; and 2.2 per cent of reticulo- cytes), leucocytosis (39-3 x 109/litre, normal range 6-1 to 17.3), mature neutrophilia (25.5 x 109/litre, normal range 3 to 11-4), monocytosis (3.1 x 109/litre, normal range 0-15 to 1.35), mild thrombocytopenia (10-2 x 109/litre, normal range 11.8 to 49.6), hyperglycemia (6-44 mmol/litre, normal range 3-08 to 5-6) and increased activities of alkaline phosphatase (222 iu/litre, normal range 35 to 161), alanine aminotransferase (94 iu/litre, normal range 0 to 55) and aspartate aminotransferase (105 iu/litre, normal range 0 to 55). The serum protein concentration was normal but the electrophoretogram showed dysproteinaemia with increased ß- and y-protein fractions. The urine contained higher than normal concentrations of bilirubin and nitrates.
Considering all the above findings, the differential diagnoses included hyperadrenocorticism, kidney or liver failure and cys- titis. An ultrasonographic examination of the abdomen was made.
Ultrasonographic examination
The abdomen was examined with a 5 MHz electronic sector transducer (SSD-500; Aloka). The examination included all the abdominal organs.
A large, round hypoechoic mass approximately 5 cm in diame- ter was found cranial to the left kidney (Fig 1). The limits of the mass were not very distinct. Its echogenicity was similar to that of the renal cortex and fairly poor compared with the surrounding mesenteric fat. The echotexture of the mass was homogeneous, but several small areas of inner calcification which produced acoustic shadowing were identified (Fig 2). The left kidney was displaced caudally but was normal in shape, size and architecture. Lateral displacement of the great abdominal vessels was observed and a vessel 5 mm in diameter penetrated into the parenchyma (Fig 1). No invasion of the caudal vena cava or abdominal aorta by the mass could be observed.
The left adrenal gland appeared abnormal and the right adrenal gland was thinner and smaller than normal with a size of 16 x 1 mm (Fig 3).
The ultrasonographic examination of the liver showed hep- atomegaly with distortion of the parenchymatous architecture (heterogeneous pattern) and the presence of several target-like lesions. These areas were oval-shaped, ranged in size from 18 x 10 to 20 x 15 mm and had an echogenic centre surrounded by a hypoechoic or anechoic rim (Fig 4). These features were highly suggestive of distant metastasis. On the evidence of these find- ings, a diagnosis of left adrenal gland carcinoma was established.
A moderate amount of echogenic fluid was also found in the dependent part of the abdomen. An ultrasound-guided aspiration
F. Liste, DVM, PhD, M. Gascon, DVM, PhD, J. Garcia de Jalon, DVM, PhD, Departamento de Patología Animal, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza-50013, Spain
M. Cuevas, DVM, I. Cuevas, DVM, Clínica Veterinaria, Avenida Tenor Fleta 119, Zaragoza-50007, Spain
Dr Liste’s present address is Department of Surgery (Section of Radiology), Tufts University, School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA
*
of the abdominal cavity revealed a viscous and bloody fluid. No ultrasonographic abnormalities were observed in the other abdom- inal organs.
Owing to its poor prognosis, the dog was euthanased at the request of the owner. At postmortem examination, the mass was white, firm on palpation and contained areas of necrosis and haemorrhage with no capsule formation. The liver was large, had an irregular contour, and contained several nodules distributed throughout. Histological examination confirmed an adrenocortical carcinoma of the left adrenal gland with atrophy of the contralat- eral gland and generalised hepatic metastasis. Microvascular inva- sion was observed as well as several areas of necrosis and calcifi- cation inside the mass (Fig 5).
Discussion
The ultrasonographic features and normal appearance of the canine adrenal glands have been described by Schelling (1991) and Grooters and others (1994, 1995) (Fig 6). A diagnosis of adrenal neoplasia can be difficult on the basis of diagnostic testing alone. Recently, false positive results have been observed with the low dose dexamethasone suppression test, the ACTH stimulation test and the ratio of cortisol to creatinine in urine. Thus, a defini-
tive diagnosis of hyperadrenocorticism should not be based on diagnostic testing alone, especially in dogs without the classical signs of the condition (Kaplan and others 1995). Ultrasonography can therefore contribute to the final diagnosis by scanning the adrenal glands and other abdominal organs (especially the liver), searching for changes in echogenicity and increases in size or metastasis. Considering that only 5 to 15 per cent of adrenocorti- cal tumours are functional and clinical signs of pheochromo- cytoma are often non-specific (Bouayad and others 1987, Poffenbarger and others 1988), a routine examination of the adrenal glands should be included in the ultrasonographic proto- col. Bilateral enlargement of the adrenal glands is consistent with pituitary-dependent hyperadrenocorticism, whereas the presence of a tumour increases the size of one gland, and results in the atro- phy of the contralateral gland because of a negative feedback mechanism. Bilateral enlargement of the adrenal glands due to adrenocortical neoplasia is very uncommon (Ford and others 1993). Liver changes in the pituitary-dependent condition include hepatomegaly and increased echogenicity compared with the spleen or renal cortex. However, a metastatic tumour frequently invades the hepatic parenchyma producing target lesions and dis- torting the normal architecture (Schelling 1991).
In the present case, a normal left adrenal gland could not be imaged by scanning the area of the left renal artery. However, the left kidney was displaced caudally by a hypoechoic mass located in its cranial pole (Fig 1), suggesting that the mass had an adrenal
origin. The ultrasonographic measurement of the thickness of the adrenal gland gives a more accurate indication of its size than measurements of length or width. Recently, a normal range of 2 to 5 mm for the thickness of the right adrenal gland has been obtained from a study of 13 dogs (Grooters and others 1995) (Fig 6). In the present case, the thickness of the right adrenal gland was only 1 mm (Fig 3). At this point, a functional adrenal tumour in the left gland was proposed as a likely diagnosis because of the atrophy of the other gland due to a negative feedback. Autonomous functional adrenal tumours can be either benign or metastatic (Penninck and others 1988). Several areas of minerali- sation were observed inside the mass, because they produced typi- cal acoustic shadowing (Fig 2). However, adrenal gland calcifica- tion does not distinguish adrenocortical adenoma from carcinoma (Penninck and other 1988). Thus, the recognition of metastatic lesions by radiography or ultrasonography is the only useful method for assessing malignancy (Reusch and Feldman 1991). The aggressive nature of the tumour was first suspected by scan- ning the hepatic parenchyma, because of the finding of target-like (bull’s eye) lesions which are diagnostic of metastasis (Lamb 1991).
Adrenal tumours have been described without a consistent echo- texture, ranging from hypoechoic to hyperechoic. In the present case, the mass had a hypoechoic texture compared with the left renal cortex which indicated the presence of areas of necrosis and haemorrhage (Poffenbarger and others 1988). The vascularisation
RK
LK
.1~
CVC
CVC
of the mass was assessed by the presence of a 5 mm vessel pene- trating into its parenchyma. However, although the caudal vena cava had been displaced, there was no vascular invasion of the vessel (Fig 1). Postmortem examination confirmed all these find- ings. Nevertheless, a histological examination showed micro- vascular invasion of adjacent tissues (Fig 5).
Abdominal ultrasonography made it possible to establish a quick diagnosis and prognosis in this dog which showed none of the classical clinical signs of hyperadrenocorticism.
References
BARTHEZ, P. Y., NYLAND, T. G. & FELDMAN, E. C. (1995) Journal of the American Veterinary Medical Association 207, 1180
BERTOY, E. H., FELDMAN, E. C., NELSON, R. W., DUESBERG, C. A., KASS, P. H., REID, M. H. & DUBLIN, A. B. (1995) Journal of the American Veterinary Medical Association 206, 651
BOUAYAD, H., FEENEY, D. A., CAYWOOD, D. D. & HAYDEN, D. W. (1987) Journal of the American Veterinary Medical Association 191, 1610
CAPEN, C. C. (1978) Tumours in Domestic Animals. 2nd edn. Ed J. E. Moulton. Berkeley, University of California Press. p 385
FELDMAN, E. C. (1983) Journal of the American Veterinary Medical Association 183, 195
FORD, S. L., FELDMAN, E. C. & NELSON, R. W. (1993) Journal of the American Veterinary Medical Association 202, 789
GROOTERS, A. M., BILLER, D. S. & MERRYMAN, J. (1995) Veterinary Radiology 36, 126
GROOTERS, A. M., BILLER, D. S., MIYABAYASHI, T. & LEVEILLE, R. (1994) Journal of the American Animal Hospital Association 30, 462
KANTROWITZ, B. M., NYLAND, T. G. & FELDMAN, E. C. (1986) Veterinary Radiology 27, 91
KAPLAN, A. J., PETERSON, M. E. & KEMPPAINEN, R. J. (1995) Journal of the American Veterinary Medical Association 207, 445
LAMB, C. R. (1991) Problems in Veterinary Medicine 3, 555
PENNINCK, D. G., FELDMAN, E. C. & NYLAND, T. G. (1988) Journal of the American Veterinary Medical Association 192, 1604
POFFENBARGER, E. M., FEENEY, D. A. & HAYDEN, D. W. (1988) Journal of the American Veterinary Medical Association 192, 228
REUSCH, C. E. & FELDMAN, E. C. (1991) Journal of Veterinary Internal Medicine 5, 3
SCHELLING, C. G. (1991) Problems in Veterinary Medicine 3, 604
VOORHOUT, G. (1990) American Journal of Veterinary Research 51, 625
VOORHOUT, G., RIJNBERK, A., SJOLLEMA, B. E. & VAN DEN INGH, T. S. G. A. M. (1990) American Journal of Veterinary Research 51, 1280
WIDMER, W. R. & GUPTILL, L. (1995) Journal of the American Veterinary Medical Association 206, 1857
Abstract
New combination treatment for otitis externa in dogs
IN ORDER to compound a new drug combination against otitis externa, ear exudates from 515 dogs with the condition were examined; 83 per cent were erythematous-ceruminous and the remainder were suppurative. The yeast Malassezia pachydermatis was isolated from 76 per cent of the dogs, often in combination with Staphylococcus intermedius, and most often from the erythe- matous-ceruminous type. The organism most commonly isolated from the suppurative type was Pseudomonas aeruginosa, in some cases together with Proteus Streptococcus and Pasteurella species. As a result of these investigations, a combination of the antifungal agent ketoconazole, the antibacterial gentamicin sul- phate, and the anti-inflammatory mazipredone hydrochloride was developed and tested in 210 dogs; 198 (94.3 per cent) became clinically and microbiologically negative within nine days and there were no adverse reactions to the treatment.
KISS, G., RADVANYI, Sz., SZIGETI, G., LUKATS, B. & NAGY, G. (1997) Journal of Small Animal Practice 38, 51 (I) and 57 (II)
Downloaded from http://veterinaryrecord.bmj.com/ on May 9, 2015 - Published by group.bmj.com
| Veterinary Record | Ultrasonographic diagnosis of an adrenocortical carcinoma in a dog |
| F. Liste, M. Cuevas, M. Gascon, J. Garcia de Jalon and I. Cuevas Veterinary Record 1997 140: 339-341 doi: 10.1136/vr.140.13.339 | |
| Updated information and services can be found at: http://veterinaryrecord.bmj.com/content/140/13/339 | |
| Email alerting service | These include: |
| Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article. |
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform
To subscribe to BMJ go to: http://group.bmj.com/subscribe/