The Use of Positron Emission Tomography-Computed Tomography Scan in the Evaluation of a Patient with Carney Complex

Abstract

A 32-yr-old woman presented with clinical hypercortisolism, including a 30-lb weight gain, central obesity, oligomenorrhea, hirsutism, and hypertension with hypokalemia. The patient reported easy bruisability, and her surgical history included bilateral breast fibrous adenomas within a myxoid stroma. Labs: K+ 2.9 mmol/liter, 0800-h cortisol 33 μg/dl; 1600-h cortisol 35 μg/dl; and 24-h urine-free cortisol 175 μg. An adrenal computed tomography (CT) revealed bilateral nodularity; a positron emission tomography (PET)-CT demonstrated F18-fluorodeoxyglucose uptake in both adrenals (Fig. 1​1 and 2​2).). The patient underwent a two-stage laparoscopic adrenal resection. Pathology revealed primary pigmented nodular adrenocortical disease (PPNAD) (Fig. 3​3). Figure 1 F18 fluorodeoxyglucose avid adrenal glands, transverse section, adrenal glands at white arrows. Standardized Uptake Values (SUV):Liver-3.0(range 2.75–3.4), left adrenal-4.45, right adrenal-3.54. Figure 2 F18 fluorodeoxyglucose avid adrenal glands, coronal section, adrenal glands at white arrows. Standardized Uptake Values (SUV):Liver-3.0(range 2.75–3.4), left adrenal-4.45, right adrenal-3.54. Figure 3 Left adrenal gland; the white arrows point to pigmented areas of the nodular cells (lipofuscin granules). Magnification 40×. Carney complex (CNC) is an autosomal dominant multiple neoplasia syndrome associated with hyperfunctioning pituitary, gonads and/or adrenals with hypercortisolism being the most common endocrine finding (1). The diagnosis of Cushing’s syndrome may be elusive: sometimes, abnormal cortisol secretion can only be demonstrated after a dexamethasone-induced stimulation (2), and adrenal CT can be equivocal (3). PET scan of the adrenals has been used to detect cancers, but PET imaging alone may be ambiguous, and the diagnostic capability is increased with PET-CT, allowing for simultaneous anatomical and functional evaluation of adrenal lesions (4). The presence of breast myxomas, PPNAD, and a PRKAR1A mutation confirmed the diagnosis of CNC in our patient; genetic analysis demonstrated a mutation of the PRKAR1A gene (IVS1–2 A>G), which has been shown before to cause PPNAD and CNC (5). The patient’s only child, a daughter, carries the same PRKAR1A mutation. This is, to our knowledge, the first report of PET-CT imaging of the adrenal glands in PPNAD. PET-CT imaging may be useful in the evaluation of patients with ACTH-independent hypercortisolism. Apparently, not all F18-fluorodeoxyglucose-avid adrenal glands contain malignancies.