Cyclic Cushing's Syndrome: Delay in Proper Diagnosis and Appropriate Treatment – Learning Lessons

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 163-194-Pituitary Disorders & Case Reports
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-182
Henrique Vara Luiz*, Bernardo Dias Pereira, Tiago Nunes da Silva, Andreia Veloza, Ana Catarina Matos, Isabel Manita, Maria Carlos Cordeiro, Luísa Raimundo and Jorge Portugal
Garcia de Orta Hospital, Almada, Portugal
Introduction: Cyclic Cushing’s Syndrome (CCS) is a rare disorder, characterized by repeated episodes of cortisol excess interspersed by periods of normal cortisol secretion. Frequent measurements of laboratory parameters are mandatory and accepted diagnostic criteria include the presence of three peaks and two troughs of cortisol production. Tests used in the differential diagnosis of CCS, such as inferior petrosal sinus sampling (IPSS), should be performed during a phase of hypercortisolism.

Clinical case: A 32-year old woman presented with weight gain and easy bruising. Her past medical history was unremarkable. Physical examination revealed no signs of hypercortisolism. Initial laboratory tests demonstrated an increase in 24 hour urine free cortisol (UFC), 147.5 and 115.5 μg/24h (normal: 15-90 μg/24h) and an abnormal response in dexamethasone suppression tests: 1 mg overnight, 8.1 μg/dL (normal: < 1.8 μg/dL) and low dose, 9.5 μg/dL (normal: < 1.4 μg/dL). Subsequent evaluation showed: ACTH 45 pg/mL (normal: 9-50 pg/mL), < 50% cortisol decrease following high dose dexamethasone supression test and exaggerated response after CRH stimulation test (96% increase in ACTH and 63% increase in cortisol). Pituitary MRI revealed a microadenoma. IPSS was postponed and performed some months later, with inconclusive results. The patient was monitored with UFC. During a period of 40 months, repeated periods of hypercortisolism alternating with normal values were noticed, and three peaks and two troughs of cortisol production were identified, suggesting the diagnosis of CCS. Signs and symptoms were intermittent, appearing during the periods of cortisol excess. She underwent transsphenoidal surgery and histological examination was consistent with ACTH-positive pituitary adenoma. Since surgical intervention the patient remains free of symptoms and has normal UFC levels, with unremarkable circadian rhythm of cortisol.

Conclusion: We report a case of CCS, caused by an ACTH-secreting pituitary adenoma. The association of fluctuating clinical picture and discrepant biochemical findings suggests CCS and frequent laboratory measurements are required to confirm the diagnosis. IPSS was probably performed during a period of normal cortisol secretion and the inconclusive results contributed to the delay in the diagnosis of Cushing’s Disease and its appropriate treatment. Therefore, prior confirmation of hypercortisolism is mandatory. Disease remission was noticed after surgery.

Nothing to Disclose: HVL, BDP, TND, AV, ACM, IM, MCC, LR, JP

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