7777 The Adrenal Tumor Volumes Help Predict Surgical Indications And Postoperative Recurrence Of PMAH

Abstract Disclosure: S. Suzuki: None. K. Ishiwata: None. Y. Ruike: None. K. Igarashi: None. S. Watanabe: None. M. Sugo: None. M. Fujimoto: None. H. Koide: None. K. Yokote: None. Introduction: Primary macronodular adrenal hyperplasia (PMAH) is characterized by benign bilateral enlarged adrenal masses, causing Cushing's syndrome (CS). Unilateral adrenalectomy of the largest gland has been proposed as a treatment for PMAH. However, there are cases of recurrence or persistence of hypercortisolism after unilateral adrenalectomy, and remaining tumor volumes might be associated. Objective: This study aimed to analyze whether tumor volume helps select treatment and predict postoperative recurrence. Patients and methods: We conducted a retrospective study of thirteen patients (five males and eight females, mean age 59 years) with CS due to PMAH in a single center. Eight patients with PMAH underwent unilateral adrenalectomy, but five PMAH were not. Long-term clinical and biochemical outcomes were analyzed in operated and non-operated patients (112±57 months after unilateral adrenalectomy and 144±49 months after initial diagnosis, respectively). Results: Eight PMAH patients who underwent unilateral adrenalectomy had total tumor volumes greater than 1500 mm2. After unilateral adrenalectomy, when the size of the remaining adrenal tumor was greater than 1000 mm2 (1053, 1268, and 1910, respectively), recurrence occurred along with enlargement of the residual adrenal tumor in two cases, and diabetes worsened in one case. However, when the size of the remaining adrenal tumor was less than 500 mm2 (18.2, 201, 214, 327, and 446, respectively), CS resolved. Among five PMAH patients who did not receive surgery, three PMAH patients with total tumor volume less than 1500 mm2 (856, 1038, and 1496, respectively) were biochemically controlled. However, in two PMAH patients with a total volume greater than 1500 mm2 (1610 and 1650), Cushing's signs, including buffalo hump and central obesity, appeared and worsened metabolic complications during follow-up. Conclusions: Our data suggest that adrenalectomy should be considered in PMAH with a total tumor volume greater than 1500 mm2. Unilateral adrenalectomy might have a risk of recurrence if the remaining adrenal tumor is over 1000 mm2. Further large-scale examination is required. Presentation: 6/3/2024