Endocrine Abstracts

Introduction: Acromegaly is a rare endocrine disorder. In 95% of cases, it is caused by a GH-secreting pituitary adenoma. Rarely, acromegaly is due to ectopic production of GH or growth hormone-releasing hormone (GHRH). Herein, we report a case of acromegaly with negative pituitary magnetic resonance imaging (MRI) and discuss its possible etiology and management.

Observation: A 75-year-old woman was referred to our department for the exploration of acquired acrofacial dysmorphic syndrome. Her past medical history included type 2 diabetes mellitus and hypertension. She presented with paraesthesia of the left hand, arthralgia, and nocturnal snoring. Neither headache nor visual impairment was reported. On physical examination, she had a body weight of 69 kg, a body height of 1 m 68, corresponding to a body mass index of 24.4 kg/m², an enlargement of facial features and hands, and a loss of dental articulation. Hormonal investigations revealed an IGF1 level of 424 ng/ml (nr=55-212), a nadir of GH under oral glucose tolerance test of 7.1 ng/ml (> 1 ng/ml), a TSH level of 1.3 mIU/l (nr:0.35-4,95), a FT4 level of 0.97 ng/dl (nr: 0,7-1,5), a FSH level of 43.9 IU/l, a LH level of 14.64 IU/l, and a prolactin level of 7 µg/l. The peak of cortisol level in response to the insulin-induced hypoglycemia test was 19.7µg/l. Further explorations showed carpal tunnel syndrome, thyroid nodule, and a mild obstructive sleep apnoea syndrome. The chest x-ray and the abdominal ultrasound were normal. Initial and repeat pituitary MRI showed a normal-sized pituitary gland with no evidence of an adenoma. Work-up for ectopic GH-secreting tumor was planned (cervical-thoraco-abdominal computed tomography scan and octreotide scintigraphy).

Conclusion: Acromegaly may be a curable cause when a pituitary adenoma is evident. However, its extra-pituitary origin remains a real challenge as to its localization and management.