Growth Kinetics of Bilateral Macronodular Adrenocortical Disease: Long-Term Imaging Follow-Up in Natural and Surgical Cohorts.

OBJECTIVE

The aim of this study is to investigate the natural growth and post-unilateral total adrenalectomy changes of bilateral macronodular adrenocortical disease (BMAD).

METHODS

Retrospective analysis included BMAD patients with ≥2 computed tomography scans: 52 in the natural course cohort (median follow-up 31 months, range 7-150) and 23 in the post-unilateral adrenalectomy cohort (median follow-up 36 months, range 2-98), with their adrenal volumes measured precisely. A linear mixed-effects model was applied to longitudinal data from patients with ≥3 computed tomography scans to analyze adrenal growth patterns.

RESULTS

In BMAD patients with a natural course, total adrenal volume ranged from 5.5 to 92.8 mL. The left adrenal volume was significantly larger than the right, and males had greater volumes than females (P < 0.001). The exponential growth model best fitted volume changes, with a median volume doubling time (VDT) of 11.82 years (range: 1.72-102.70) and a median specific growth rate (SGR) of 5.87%/year (range: 0.67% to 40.41%). In post-unilateral adrenalectomy patients, contralateral adrenal volume showed a significant postoperative increase (P < .05), with exponential growth (median VDT: 9.08 years, range: 2.56-61.86; median SGR: 7.63%/year, range: 0.17% to 29.96%). Receiver operating characteristic analysis demonstrated that postoperative contralateral adrenal volume had superior diagnostic performance (area under the curve = 0.913, 95% CI: 0.813-1.000) for diagnosing autonomous cortisol secretion.

CONCLUSION

BMAD exhibits exponential growth despite variability in size and growth speed, which supports using VDT and SGR for the individualized growth assessment and imaging follow-up. Postoperative adrenal volume may help assess autonomous cortisol secretion status after unilateral adrenalectomy.