Endocrine Abstracts

Introduction: Primary adrenocortical carcinoma (ACC) is a rare adrenal tumor and bilateral tumors are reported in 10% of total patient with ACC in Japan. We present a case of bilateral ACCs accompanied by severe muscle weakness.

Case report: A 63-year-old male patient with bilateral adrenal masses was referred to our department for the examination and treatment of progressive muscle weakness and appetite loss lasting over 2 months. He was not able to stand up by himself because of loss of muscle power. Computed tomography showed bilateral huge adrenal tumors (110 mm in diameter each) extending into the inferior vena cava. No significant uptake was found in 131-I MIBG scintigraphy. Plasma levels and 24-h urinary excretion of catecholamines and their metabolites were normal. Serum cortisol levels were slightly low and plasma ACTH levels were slightly high. These findings suggested presence of primary adrenocortical insufficiency and we began replacement therapy with low doses of hydrocortisone. His symptoms such as appetite loss and muscle weakness were immediately improved after replacement therapy and it enabled him to walk by himself. To establish the diagnosis, we performed open biopsy and histological findings revealed adrenocortical carcinoma. In spite of medical therapy with mitotane, the development of ACCs was aggressive and he died from multiple organ failure.

Conclusion: To the best of our knowledge, a case of ACC accompanied by serious muscle weakness is very rare. Bilateral ACCs can cause primary adrenal insufficiency by their invasion to both adrenal glands. It is known that muscle weakness can be developed in patients with adrenocortical insufficiency but its exact mechanism is still unknown. Marked and immediate improvement of muscle power after the hydrocortisone replacement therapy strongly suggests that cortisol deficiency plays a critical role in developing severe muscle weakness in this case.