PMC10378588_01
Adrenal ultrasonography of a dog performed at the initial presentation [(A), right adrenal tumor and (E), left adrenal gland], after 168 days of trilostane treatment [(B), right adrenal tumor and (F), left adrenal gland], after 280 days of trilostane treatment [(C), right adrenal tumor and (G), left adrenal gland], and after one year of trilostane treatment [(D), right adrenal tumor and (H), left adrenal gland]. The size of the right adrenal tumor was decreased within one year [(A, D), 26 x 19mm   11.6 x 10mm]. The size of the cranial pole of left adrenal gland was slightly increased within 1 year [(E, H), 4.36mm   5.8mm].
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F1
Abdominal ultrasonography showed gallbladder sludge, one heterogenous hepatic mass (15 x 5 mm), and a right adrenal tumor (26 x 19 mm) with local invasion of the CVC; the left adrenal gland was within normal limits (Figure 1). During the treatment period, while the size of the adrenal tumor decreased, there was a tendency for the size of the contralateral adrenal gland to increase (Figure 1).
Cytology following fine-needle aspiration of the right adrenal tumor (A) and hepatic mass (B) in a dog with metastatic adrenocortical carcinoma. Cells with anisocytosis, a basophilic cytoplasm, and cytoplasmic vacuolization suspected to be originating from the adrenal cortex are seen in both (A, B). These findings indicate that the hepatic mass likely represented a metastatic ACC (Diff-Quik stain, original magnification 1000x).
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F2
Fine-needle aspiration cytology performed by a clinical pathologist on the adrenal tumor and hepatic mass revealed cells with anisocytosis, round nuclei, a basophilic cytoplasm, and cytoplasmic vacuolization; these were suspected to have originated from the adrenal cortex (Figure 2).
Post-contrast CT images obtained at the time of initial presentation [(A, B, D) transverse view; (C) dorsal view] and after 1 year of trilostane treatment [(E, F, H) transverse view; (G) dorsal view]. During therapy, the diameter of the adrenal tumor decreased [(B, C, F, G) white arrowhead]. The metastatic liver mass with heterogenous enhancement [(A) white arrow] resolved after trilostane treatment (E). No significant changes of ground-glass opacities [GGOs; (D, H) black arrowhead] and lung masses [(D, H) black arrow] were found after treatment.
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F3
A CT scan showed a right adrenal tumor (width x height x length, 17 x 21 x 22 mm3) with CVC invasion, a hepatic mass (width x height x length, 13 x 9 x 22 mm3), and >20 soft tissue attenuating solid masses (longest diameter, 3-6 mm) and ground-glass opacities (GGOs) throughout the lungs, indicating suspected metastasis from ACC (Figure 3). In addition, no additional metastasis was observed (Figure 3).