Endocrine Abstracts

JOINT2538

Introduction: Paraneoplastic Cushing’s syndrome is an uncommon cause of endogenous hypercortisolism. Only 6% of Cushing’s syndrome was caused by ectopic ACTH secondary to neuroendocrine tumors [1]. These tumors may be occult and difficult to find, and imaging results are often inconclusive.

Observation: We report a case of a 21 year old patient, who presented with a Cushing’s syndrome confirmed by 48-hour low-dose dexamethasone test. On physical examination, he had melanoderma, muscle atrophy, purple abdominal striae and centripetal obesity. The ACTH-dependent character was confirmed by high ACTH level. The diagnosis was complicated with diabetes, hypertension with severe hypokalemia, cerebral and iliac thrombophlebitis and pulmonary embolism and gonadotropin deficiency. Pituitary MRI revealed a 4.5 mm pituitary microadenoma. The patient underwent total transsphenoidal hypophysectomy and the anatomopathological examination confirmed the diagnosis of pituitary adenoma with immunohistochemistry confirming ACTH-binding character. The post operative follow-up showed the persistence of clinical and biological Cushing’s syndrome with high levels of ACTH. Cervical thyroid echography and thoracic-abdominal-pelvic (TAP) CT scan showed no abnormalities besides bilateral adrenal hyperplasia and bilateral pulmonary parenchymal condensation with no pathological fixation on octreotide scintigraphy. Pleural biopsy showed a cytological aspect of tuberculosis without histological signs of malignancy. The patient underwent bilateral adrenalectomy. During the 13 years follow up the ACTH levels remained high with negative anatomic and functional imaging. At the age of 34 years old, CT TAP showed thickened micronodules of the two basal pyramids, well rounded and non-specific and octreotide scintigraphy showed a 06 mm left antero-basal pulmonary nodule intensely fixating octreotide. The patient was referred to thoracic surgery.

Conclusion: This case highlights the challenges of paraneoplastic Cushing’s syndrome and the importance of vigilance in identifying ectopic ACTH-secreting tumors which can remain occult for years.Reference1. Valassi E, Franz H, Brue T, Feelders RA, Netea-Maier R, et al. Diagnostic tests for Cushing’s syndrome differ from published guidelines: data from ERCUSYN. Eur J Endocrinol. 2017; 176: 613-24.