Endocrine Abstracts

Introduction: Pseudoacromegaly encompasses a group of conditions in which patients have clinical features of acromegaly or gigantism, but no GH or IGF-1 excess. With systematically reviewing all published cases (n=76) of patients with pseudoacromegaly who were evaluated due to a clinical suspicion of acromegaly, we identified key distinguishing features which need to be recognized.

Materials and Methods: A systematic search using the terms pseudoacromegaly, acromegaloidism and acromegaloid was conducted. Pseudoacromegaly cases were carefully checked to ensure they met eligibility criteria: 1) presentation suggestive of acromegaly and investigation triggered by acromegaly-related manifestations; 2) acromegaly was excluded based on normal serum GH, IGF-1 and/or GH suppression on oral glucose tolerance test (OGTT-GH); 3) definitive diagnosis of the underlying pseudoacromegaly condition was established.

Results: Of the 76 included cases, 47 (62%) were males, with mean ages at presentation 28±16 yrs (mean±SD) and at first acromegaloid symptoms 17±10 yrs. Most cases were reported from Asia (42%). Over half 57% were directly referred to Endocrine departments. The most common conditions were pachydermoperiostosis (47%) and insulin-mediated pseudoacromegaly (24%), followed by Cantú (8%) and Berardinelli-Seip (4%) syndromes. Insulin-mediated pseudoacromegaly cases were more often referred to endocrine departments, whereas pachydermoperiostosis to non-endocrine physicians. Acromegaloid facies (75%) and acral enlargement (80%) were the most common features; other prevalent acromegaloid features included hyperhidrosis (36%), pachydermia (32%), arthralgia (29%), macroglossia (25%), prognathism (25%), acanthosis nigricans (25%) and tall stature (20%). Prevalence of acromegaloid physical features and tall stature was higher in cases referred to endocrine specialists (33% vs 6%; P=0.003). GH/IGF-1 axis assessment was heterogeneous: random GH was reported in 65%, IGF-1 in 79%, OGTT-GH in 51%. GH excess was more frequently ruled out based on 2 tests combined (53%); 3 tests were applied in 22%. Pituitary MRI was performed in 30 cases, being normal in 19, while a pituitary adenoma or hyperplasia were reported in 8 and 3 patients, respectively. Investigation patterns differed between cases managed by endocrine and non-endocrine specialists, the former requesting more often IGF-1, OGTT-GH and pituitary MRI.

Conclusions: Pseudoacromegaly is a challenging entity that may be encountered by endocrinologists, with pachydermoperiostosis and insulin-mediated pseudoacromegaly being the conditions most identified as mimicking acromegaly. Adequate assessment of GH/IGF-1 is crucial to rule out acromegaly, which may be better performed by endocrine specialists. Pituitary incidentalomas are common in the pseudoacromegaly setting and require careful judgment to prevent inadequate management.