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34 Adrenal Mass, Incidental

Adrenal Mass, Incidental Client Education
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• Functional: clinical syndrome dependent on
BASIC INFORMATION
hormone produced. marginated mineralization typical of
benign lesion
Definition ○ Hyperadrenocorticism • Abdominal ultrasound
Adrenal mass discovered inadvertently during ○ Occult hyperadrenocorticism ○ Evaluate gland shape, asymmetry between
abdominal imaging (typically ultrasound) ○ Primary hyperaldosteronism glands and invasion of surrounding tissues.
performed for any reason other than suspected ○ Pheochromocytoma ○ Echogenicity varies.
adrenal disease ○ Findings suggesting malignancy are any
DIAGNOSIS tumoral diameter > 2 cm, evidence of
Synonym metastasis, or invasion into surrounding
Incidentaloma Diagnostic Overview tissues and/or vena cava.
Definitive diagnosis of mass type requires biopsy ○ Atrophy of contralateral adrenal gland
Epidemiology or surgical removal and histopathology. Deter- suggests tumor is secreting cortisol or
SPECIES, AGE, SEX mination of functionality requires biochemical hormone with glucocorticoid activity.
• Dogs: incidence estimated at 4%. Affected testing. Factors that determine the aggressiveness
dogs typically > 9 years old and midsized of the diagnostic approach include original Advanced or Confirmatory Testing
to large breed. reason for performing abdominal imaging, • Functionality can be determined by various
• Cats: incidence and signalment unknown. the severity of concurrent problems, patient tests:
age, likelihood the mass is functional and/or ○ For cortisol-secreting tumor, low-dose
GENETICS, BREED PREDISPOSITION malignant, size and invasiveness of the mass, dexamethasone suppression test preferred
Breed predisposition varies with type of mass. and the client’s desires. (p. 1360)
○ For sex-hormone-secreting tumor, ACTH
Clinical Presentation Differential Diagnosis stimulation test with measurement of sex
DISEASE FORMS/SUBTYPES • Tumor hormones (p. 1300)
• An adrenal tumor should be suspected when ○ Adrenocortical adenoma or carcinoma ○ For aldosterone-secreting tumor, mea-
there is loss of the typical adrenal gland shape ○ Pheochromocytoma surement of aldosterone likely sufficient
(regardless of size), asymmetry in shape and ○ Lipoma/myelolipoma (p. 1303)
size between affected and contralateral ○ Metastasis from elsewhere; pulmonary, ○ For pheochromocytoma, measurement of
adrenal glands, or infiltration of vasculature mammary, prostatic, gastric, and pan- blood pressure and potentially urinary
or surrounding soft tissues. creatic carcinomas and melanoma most catecholamines
• May be functional (i.e., secrete a hormone) likely • Abdominal computed tomography (CT)
or nonfunctional. Functional types include • Nontumorous mass ○ Poor glandular demarcation, irregular
○ Cortisol-secreting (p. 485) ○ Abscess contrast-enhancement, and a nonhomo-
○ Sex hormone–secreting (p. 490) ○ Granuloma geneous texture suggest malignancy.
○ Aldosterone-secreting ○ Hematoma ○ Vascular invasion can be determined with
○ Pheochromocytoma (p. 785) ○ Nodular hyperplasia high but not perfect accuracy.
• May be benign or malignant. May be • Cytology
primary to the adrenal gland or a metastatic Initial Database ○ Skill is required to perform ultrasound-
lesion • Repeat abdominal ultrasound to ensure the guided aspirates of adrenal gland tumors.
mass is a consistent finding. ○ Aspirates not recommended if systemic
HISTORY, CHIEF COMPLAINT • Review history and physical exam for evi- blood pressure is significantly elevated.
• By definition, these tumors are an incidental dence of functionality (i.e., signs suggesting ○ Cytology has 90%-100% accuracy for
finding. hyperadrenocorticism, excess sex hormones, differentiating cortical from medullary
• Nonfunctional: usually no clinical signs. hyperaldosteronism, or pheochromocytoma) origin; not reliable for distinguishing
Rarely cause ascites or pelvic limb edema • Nonfunctional tumor benign from malignant
due to vena cava invasion; patient presents ○ CBC, biochemical profile, urinalysis, and
for enlarged abdomen or limb swelling. blood pressure often unremarkable TREATMENT
• Functional: questioning may reveal signs ○ Thoracic radiographs usually normal;
consistent with hypercortisolemia, excess adrenal tumors rarely metastasize to lungs Treatment Overview
sex hormones, hyperaldosteronism, or • Functional tumor: see chapters on hyperad- The same factors that determine the aggres-
pheochromocytoma. renocorticism, occult hyperadrenocorticism, siveness of the diagnostic approach affect the
pheochromocytoma, and hyperaldosteronism aggressiveness of the therapeutic approach.
PHYSICAL EXAM FINDINGS (pp. 485, 490, and 785) for information Medical and surgical options exist; if the mass
• Nonfunctional: rarely, palpable adrenal mass related to expected findings. is believed to be benign and nonfunctional,
• Functional: may have findings consistent ○ CBC, biochemical profile and urinalysis monitoring is sufficient.
with hypercortisolemia, excess sex hormones, ○ Thoracic radiographs
hyperaldosteronism, or pheochromocytoma ○ Blood pressure Acute and Chronic Treatment
• Abdominal radiographs • If the mass is suspected to be malignant,
Etiology and Pathophysiology ○ Occasionally, mass evident cranial to the adrenalectomy is preferred.
• Of primary adrenal tumors, 75% are kidneys ○ Medical therapy may be indicated prior
adrenocortical. ○ May contain mineralization whether to surgical intervention (pp. 35 and 785).
• Nonfunctional: rarely, manifestations occur benign or malignant; diffuse, ill-defined • If adrenalectomy is not indicated or not
due to invasion of vena cava or adjacent mineralization usually associated with an option (e.g., metastatic disease, severe
organs. adrenal neoplasia, but discrete, well- comorbid disease, very advanced age) and

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