Endocrine Abstracts

JOINT2170

Introduction: Cushing’s disease, an endocrine disorder caused by ACTH-secreting pituitary adenomas, encompasses a wide spectrum of systemic complications. While metabolic, cardiovascular, and musculoskeletal alterations are common manifestations, tendon ruptures are exceptionally rare as an initial presentation. These ruptures reflect the profound impact of chronic hypercortisolism on connective tissue integrity, highlighting the need for vigilance in diagnosing atypical presentations of this condition.

Case Report: A 40-year-old woman presented to the endocrinology consultation with a two-year history of amenorrhea and infertility following the discontinuation of oral contraceptives, accompanied by progressive hirsutism, weight gain, easy bruising, and proximal muscle weakness. Additionally, she had a bilateral Achilles tendon rupture, with no preceding trauma or excessive physical exertion. Her medical history was relevant for hypertension and prediabetes, with no medication. On presentation to our clinic, she reported proximal myopathy and had a BMI of 21.1kg/m² with no evident signs of Cushing’s disease. Biochemical evaluation revealed elevated 24-hour urinary free cortisol (138 nmol/L; reference: 11.5–102), a lack of suppression on a low-dose dexamethasone suppression test (post-dexamethasone cortisol: 7.2 µg/dl), and elevated salivary cortisol (0.4 µg/dl; reference: <0.27). ACTH levels were elevated at 40 pg/ml, suggesting an ACTH-dependent cause. Magnetic resonance imaging identified an 11 mm right-sided pituitary macroadenoma. The patient was started on metyrapone 500mg/day while awaiting surgery. She was submitted to an uneventful endoscopic transsphenoidal resection, which confirmed a corticotroph pituitary neuroendocrine tumor with positive ACTH immunostaining. Postoperatively, the patient demonstrated significant clinical improvement, with resolution of muscle weakness and normalization of cortisol levels on follow-up.

Discussion: This case highlights the broad and atypical spectrum of presentations in Cushing’s disease. Bilateral Achilles tendon rupture is an uncommon yet severe complication attributed to the detrimental effects of chronic hypercortisolism on connective tissue. In fact, cortisol excess disrupts collagen synthesis by impairing fibroblast function and increasing matrix metalloproteinase activity, which degrades the extracellular matrix. These effects weaken tendons and predispose them to rupture, even in the absence of significant trauma. Proximal myopathy further exacerbates tendon vulnerability by altering biomechanical stress patterns. This case underscores the importance of recognizing atypical manifestations of Cushing’s disease, such as bilateral tendon rupture, and highlights the need for multidisciplinary management to optimize patient outcomes. A high index of suspicion and thorough clinical evaluation are essential for early diagnosis and treatment of this condition.