8034 Putting the Pieces Together: Carney Complex, A Hyper-Rare Congenital Neoplastic Syndrome

Abstract Disclosure: G. Fontanazza: None. A.R. Conforti: None. K. Bird: None. M. Caplan: None. Intro: Carney complex (CNC) is an autosomal dominant disorder characterized by multisystem neoplasia that primarily affects the thyroid, pituitary, and adrenal glands. Its prevalence is not well established, as only 750 cases have been reported worldwide. This condition arises when an inactivating PRKAR1A gene mutation results in dysregulated cell proliferation and tumorigenesis. Complications include the potential for malignant transformation and systemic manifestations, necessitating comprehensive management and ongoing surveillance of disease progression. Case: The patient is a 58-year-old woman who initially presented as a teenager with complaints of hirsutism, truncal obesity, and violaceous abdominal striae. Initial workup revealed a low-dose dexamethasone suppression test that resulted in a non-suppressed cortisol levels. She also had undetectable adrenocorticotropic hormone (ACTH) levels. Imaging revealed no pituitary masses and demonstrated slight bilateral adrenal enlargement without adenomas. Despite these results, she was empirically treated for presumed pituitary-dependent Cushing's disease and received external beam radiation. Despite treatment, she continued to have episodes of hypercortisolism that were apparent clinically and biochemically. Over time, she developed a cardiac myxoma with six cerebrovascular accidents and multiple benign tumors. As an adult, she underwent extensive endocrine evaluation, which revealed urine cortisol excretion that paradoxically rose in response to dexamethasone. ACTH levels were always undetectable, even when she was significantly hypercortisolemic. Genetic testing revealed a homozygous mutation in the melanocortin-2 receptor (MC2R). Accordingly, she elected to have a bilateral adrenalectomy and was started on hydrocortisone and fludrocortisone. Discussion: The patient exhibited ACTH-independent micronodular adrenal hyperplasia and its most frequent variant, primary pigmented nodular adrenocortical disease. Bilateral pigmented nodular hyperplasia is a finding which can occur in association with CNC and cause episodic hypercortisolism. These patients have been shown to respond to dexamethasone with a paradoxical increase in glucocorticoid excretion. While management requires ongoing surveillance, this patient had not been diagnosed until later in life and did not have regular screening. When speculating on the late detection, her story reflects the parable of the blind men and the elephant: endocrinology managed Cushing's disease, cardiology managed atrial myxoma, and oncology managed osteochondromyxomas. Limited perspective with specialized management and an inability to see the whole picture led to prolonged diagnosis with unfortunate sequelae. This report encourages physicians to develop perspective awareness and to consider the entire picture when treating patients. Presentation: 6/2/2024