SAT-016 - Leukocytosis as A Diagnostic Indicator of Cushing Syndrome

Introduction: Cushing syndrome (CS) is a rare glucocorticoid excess disorder. The diagnosis of CS may be challenging, especially in the early stages devoid of the classic signs of moon facies, facial plethora, central obesity, proximal myopathy, and wide purple abdominal striae. Early diagnosis is critical due to its associated increased risk of cardiovascular events, infection, and obesity.

Case: We present a case supporting that a persistent leukocytosis should prompt further workup to include consideration of diagnosis of CS. A 54-year-old female with a PMHx HTN, HLD, T2DM, CAD s/p 3v stent, class II obesity, and CKD3a, initially presented with fatigue, worsening anxiety, nocturia, and weight gain. She had been previously worked up for a one- year history of a persistent leukocytosis (wbc 10.6-14.9, reference range 4.2-9.4) with neutrophilia and lymphocytopenia and a high neutrophil-to-lymphocyte ratio without evidence of leukemia or myeloproliferative neoplasm. Due to the presence of multiple unusual comorbidities for age and a persistent unexplained leukocytosis, she underwent workup for possible CS with 24-hour urine free cortisol (UFC) and 1mg dexamethasone suppression (DST) tests. She had not received oral, intra-articular, or inhaled corticosteroids. 24-hour UFC 78mcg/24hr (6-42) and 1mg DST cortisol level 5.37mcg/dl. DHEAS level 185 mcg/dl and ACTH level 21.6 pg/ml. Subsequent 8mg DST revealed a greater than 50 percent reduction of cortisol level, suggesting a pituitary ACTH-source. MRI demonstrated a 4mm pituitary adenoma. She was referred to the NIH for management of Cushing disease. She thereafter underwent transsphenoidal resection of the pituitary adenoma. Subsequent lab testing demonstrated resolution of the neutrophil-predominant leukocytosis.

Discussion: Glucocorticoid-induced leukocytosis results from multiple mechanisms, including increasing release of polymorphonuclear leukocytes (PMNs) from the bone marrow, rapid demargination from intravascular marginated pools of PMNs, delayed neutrophil and expedited lymphocyte apoptosis, and reduced migration of intravascular PMNs into tissue. In the absence of autoimmune disease, active infection, active smoking, and lymphoproliferative disorders, which are known causes of leukocytosis, CS should be considered due to its severe long-term effects if not diagnosed early. In a study by Paja et al. that examined leukocyte counts six months prior to CS diagnosis, a leukocytosis above 8000 and lymphocyte percentage below 24% had an 89.7% specificity of CS diagnosis, and the presence of at least one of these two values had a 97.3% sensitivity. This case highlights that characteristic leukocyte changes, in addition to the presence of other features of hypercortisolism, should serve as a strong prompt
to initiate further evaluation for CS.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*