Case Study

Clinical Addison’s disease with bilateral adrenal masses in a 14 year old FS Beagle

A 14-year-old FS Beagle presented for lethargy and acting not quite herself. Urinalysis showed an increased pH, low specific gravity, and hematuria. An ACTH stimulation was performed on the dog, and results were consistent with a diagnosis of hypoadrenocorticism.

Sonographic Differential Diagnosis

Bilateral non invasive adrenal masses. In light of clinical Addison`s disease, bilateral benign neoplasia such as adenomas or myelolipomas are likely. The diagnosis of nonfunctional adenocarcinoma or pheochromocytoma (potentially functional) is considered less likely.

Image Interpretation

Both adrenal glands were enlarged and nodular with mixed echogenicity. Neither appeared to invade into the adjacent vasculature (phrenic vein, vena cava). The left adrenal gland showed cranial focal capsular expansion, and the right adrenal showed circumferential capsular expansion. Complete loss of corticomedullary definition was noted in both glands, suggestive of a potentially benign bilateral destructive process.

DX

Hypoadrenocorticism (Addison's disease) with concurrent adrenal masses

Outcome

Serial blood pressures were normal in this patient. The patient was treated for Addison`s disease and managed well clinically. The owner declined further diagnostics or surgery.

Comments

Other cases with this type of adrenal presentation have been diagnosed as myelolipoma and adenoma but this is the only one in our record that had clinical Addison`s disease. The infiltrative process likely destroyed the glandular tissue responsible for cortisol secretion. The normal blood pressures reduce the likelihood of pheochromocytoma.