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Adrenocortical Neoplasia 35

yet clinical signs related to a functional • Initial monthly ultrasound is recommended Technician Tips
mass develop with time or are recognized to determine the rate of mass growth and Functional adrenal test samples may require
VetBooks.ir • Mitotane is the only true chemotherapeutic ○ If the mass has not increased in size after before obtaining a sample. Diseases and Disorders
retrospectively, lifelong medical therapy can
changes in the adrenal gland appearance.
special handling; instructions should be read
be instituted.
3 months, repeat ultrasound q 3 months.
Client Education
option and is effective for adrenocortical
tumors only. ○ If the mass enlarges, changes in appear- Determining functionality of an adrenal tumor
ance, compresses, or infiltrates surrounding
• Trilostane is used in cats with cortisol- blood vessels or soft tissues or if clinical can be challenging. However, knowledge of
secreting tumors. signs suggesting tumor functionality functionality is crucial for preoperative and
develop, consider adrenalectomy. postoperative management or successful medical
Possible Complications therapy.
• Adrenalectomy should be undertaken only PROGNOSIS & OUTCOME
by experienced surgeons in a hospital with SUGGESTED READING
a well-equipped intensive care unit (ICU) • Prognosis varies with type of tumor and Cook AK, et al: Clinical findings in dogs with
and 24-hour observation and care. therapy; survival can be months to years. incidental adrenal gland lesions determined by
• Postoperative complications include pancre- • Benign tumor: excellent to good ultrasonography: 151 cases (2007-2010). J Am Vet
atitis, pulmonary thromboembolism, acute • Functional tumors: see relevant chapter Med Assoc 244:1181-1185, 2014.
renal failure, septic peritonitis, hypoadreno- • Malignancy, larger tumor size, vena cava AUTHOR & EDITOR: Ellen N. Behrend, VMD, PhD,
corticism, hypotension, cardiac arrhythmias, thrombosis, and presence of metastases DACVIM
and cardiac arrest. associated with shorter survival
• Mortality rate for adrenalectomy is approxi-
mately 10%-25%. PEARLS & CONSIDERATIONS
Recommended Monitoring Comments
• A conservative approach (i.e., monitoring) • Subtle clinical signs of functionality may
is indicated if become apparent with careful questioning
○ No suggestion of malignancy is found of owner.
○ Tumor is < 2 cm in diameter • An aggressive diagnostic or therapeutic
○ Functional tumor is not suggested by clinical approach is not always warranted.
signs or routine blood and urine tests

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Adrenocortical Neoplasia Available Client Education
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BASIC INFORMATION ASSOCIATED DISORDERS Etiology and Pathophysiology
• Hyperadrenocorticism (HAC) (p. 485) • ΗAC is due to an adrenocortical tumor in
Definition • Hyperaldosteronism approximately 15% of dogs and 20% of cats
Tumors of the adrenal cortex that can be benign (p. 485).
or malignant; they may also be nonfunctional ○ Half are adenomas and half carcinomas.
or functional (e.g., secrete cortisol, sex hor- Clinical Presentation ○ Autonomous production of cortisol
mones, or aldosterone). These can include DISEASE FORMS/SUBTYPES (usually) or a progestin (e.g., progesterone,
incidentally identified adrenal tumors. Adrenal • Functional: secrete cortisol, sex hormones 17-hydroxy-progesterone) inhibits ACTH
medullary neoplasia is discussed separately or aldosterone production, resulting in atrophy of the
(p. 785). • Nonfunctional contralateral adrenal cortex.
○ Cortisol excess causes clinical signs of
Synonyms HAC.
• Adrenocortical carcinoma or adenoma HISTORY, CHIEF COMPLAINT • Hyperaldosteronism is usually due to a
• Adrenal-dependent hyperadrenocorticism • If functional, clinical signs depend on unilateral adenoma or carcinoma.
(p. 485) hormone(s) being secreted. ○ Clinical signs are due to aldosterone excess
• Hyperaldosteronism • If nonfunctional, often have normal physical causing hypokalemia and hypertension.
• Incidental adrenal tumor or “incidentaloma” examination; can also present for nonspecific • On occasion, other hormones may be secreted.
(p. 34) signs related to space-occupying lesion (e.g., ○ Cortisol intermediates (e.g., desoxycorti-
costerone) causes clinical signs of HAC.
Epidemiology anorexia) ○ Androgens cause signs consistent with
SPECIES, AGE, SEX male behavior (e.g., roaming, spraying,
• Cortisol-secreting adrenocortical tumors PHYSICAL EXAM FINDINGS growth of penile barbs in male cats).
○ Dogs: > 9 years old • If functional, findings depend on hormone(s)
○ Cats: median 12.3 years old secreted. DIAGNOSIS
• Aldosterone-secreting tumors: cats > 10 years • If nonfunctional, examination often normal;
old can have findings related to vena cava inva- Diagnostic Overview
• Incidentaloma: middle-aged to older dogs sion (e.g., ascites) • Most dogs with functional adrenocortical
and cats • An abdominal mass may be palpable. neoplasia have clinical signs consistent with

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