Acromegaly Without Localization: A Case Report
Introduction: Growth hormone secreting pituitary adenomas are the cause of acromegaly in over 99% of patients. Most of these tumors are large and almost always visible on sellar magnetic resonance. Acromegaly secondary to a very small pituitary microadenoma not visualized on sellar magnetic resonance is rare, as well as an ectopic source.
Case Report: 69-year-old woman, with hypertension, type 2 diabetes mellitus, mixed dyslipidemia and obstructive sleep apnea syndrome. She was referred to the Endocrinology outpatient department due to acromegaloid features. On examination, she had frontal bossing, enlarged nose, prognathism, diastema and acral enlargement. Laboratory tests (three measurements) were compatible with acromegaly, which was confirmed by the oral glucose tolerance test. Prolactin and the other pituitary axis were normal. Chromogranin A, insulin, urinary dopamine and noradrenaline and calcitonin were normal. Sellar magnetic resonances (3.0 T magnet) revealed no pituitary lesion and the body computed tomography and the octreoscan detected no ectopic tumour. The echocardiogram was normal, the thyroid ultrasound suggested a multi-nodular goiter, the abdominal ultrasound revealed liver steatosis and the colonoscopy showed sigmoid diverticulosis and a sigmoid polyp, which was excised. The patient started treatment with a long-acting somatostatin analog, with insulin-like growth factor 1 normalization. Four years later, she is clinically and biochemically controlled and without therapy adverse effects. The tumour remains undetected.
Discussion: This case report reinforces that acromegaly complications not related to tumour compression are independent of its size – though the tumour remains undetected, our patient presents multiple comorbidities possibly related to the disease. Currently, there is no consensus for the treatment of patients with acromegaly and negative pituitary imaging. In fact, it represents a diagnostic challenge since an ectopic etiology although rare must be excluded. Despite in other series surgical exploration identified microadenomas not diagnosed on magnetic resonance, medical treatment remains an option.
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