Endocrine Abstracts

We present the case of a 34-year old female presenting with intermittent episodes of fatigue, proximal muscle weakness, facial swelling and poor concentration, only evident in the winter months. After many negative tests, the testing for Cushing’s syndrome eventually became positive, a few years after initial symptoms. CT revealed a 25mm thymic mass and bulky adrenals. Pituitary MRI showed an ill-defined mass. An IPSS confirmed a peripheral source of ACTH, Nuclear medicine octreotide scanning confirmed a (non-avid) 25mm thymic nodule, likely the source of ectopic ACTH production. Following resection of the thymoma, cortisol levels were low (26nmol/l; ACTH<5ng/l), thus our patient required hydrocortisone until adrenal recovery (6 months). MEN screening was negative. Histopathology revealed a well-differentiated grade 1 thymic NET, Ki67 5%. Follow-up imaging and biochemistry for the first 9 years showed no disease recurrence with no symptoms. 9-years post operation, she reported low mood, fatigue, postural dizziness and bloating. ONDST again showed full suppression of cortisol. Subsequent cross-sectional imaging demonstrated two new, indeterminate, soft tissue nodules. Gallium-68 PET Dotatate scan showed no avid lesions. ONDST a year later still showed full suppression of cortisol. Repeat MRI though showed interval growth, raising concern for disease recurrence. The patient then reported worsening fatigue and new weight gain. Given symptom recurrence and MRI findings, an ONDST was repeated, now showing slightly unsuppressed (76nmol/l) cortisol, which along with the radiological findings, suggested Cushing’s syndrome recurrence. Subsequent testing showed increasing cortisol excess. She further developed early morning waking, facial puffiness, abdominal bloating and hirsutism. Repeat Gallium 68-Dotatate scan showed a mildly avid mediastinal lesions; the primary tumour in 2015 was not octreotide avid. Our patient underwent a right thoracotomy resection. Histopathology revealed atypical carcinoid NET (Ki67 was variable, approximately 5% but up to a maximum of 20% in small hotspots). She has biochemical remission of Cushing’s syndrome post operatively with prolonged adrenal suppression. Our case highlights the challenges of recurrence of cyclical Cushing’s syndrome many years post initial presentation. The symptoms and radiological findings predated the biochemical confirmation of Cushing’s syndrome and should be highlighted for follow up pathways.