From cortisol-producing adrenal adenoma to atrial myxoma, through nivolumab-induced hypophysitis: a complicated case report of Carney Complex.

Purpose: Carney complex (CNC) is a rare, autosomal dominant syndrome, most commonly caused by PRKAR1A gene mutations and characterized by pigmented skin and mucosal changes with multiple endocrine and non-endocrine tumours. This case report highlights the diagnostic challenges associated with CNC in a patient with multiple neoplasms and a complex medical history, including cortisol-producing adrenal adenoma, breast cancer, melanoma, and atrial myxoma.

Methods: We report the case of a 41-year-old woman with a medical history of left adrenalectomy for cortisol producing adenoma (2005) with no sign of adrenal insufficiency at follow-up, right mastectomy for BRCA1/2 negative carcinoma (2013) and left parotid BRAF-V600E wild-type melanoma (2019), treated with nivolumab adjuvant therapy. In August 2019, following the fifth nivolumab administration, the patient developed central hypocortisolism due to iatrogenic hypophysitis, confirmed by brain MRI and properly treated with oral hydrocortisone. Nivolumab was discontinued due to the patient's decision. In October 2020 and April 2021, the patient had ischaemic strokes, requiring systemic thrombolysis. Echocardiographic examination then revealed a left atrial mass, with histological finding of myxoma.

Results: Given the rarity of this neoplasm and the suspicion of a syndromic disorder, a genetic evaluation was conducted, which confirmed a PRKAR1A gene mutation and the diagnosis of Carney complex.

Conclusion: This case illustrates the diagnostic challenges in CNC, especially in patients with multiple tumourous manifestations and a wide spectrum of life-threatening clinical presentations. It underscores the importance of a multidisciplinary approach to diagnose and manage rare diseases, improving patient outcomes through timely genetic testing and coordinated care.