This month the PNA Medical Corner highlights an article co-authored by Dr. Albert Beckers, a longtime member of the PNA. The study looks at the case of a 7-year-old boy with a pituitary tumor due to a gene mutation. They conclude that not all tumors of this type respond to pasireotide.
AACE Clin Case Rep
. 2021 Dec 16;8(3):119-123.
doi: 10.1016/j.aace.2021.12.003. eCollection May-Jun 2022.
• PMID: 35602875 PMCID: PMC9123570 DOI: 10.1016/j.aace.2021.12.003
Abstract
Background: Our objective was to describe the clinical course and treatment challenges in a very young patient with a pituitary adenoma due to a novel aryl hydrocarbon receptor-interacting protein (AIP) gene mutation, highlighting the limitations of somatostatin receptor immunohistochemistry to predict clinical responses to somatostatin analogs in acromegaly.
Case report: We report the case of a 7-year-old boy preventing with headache, visual field defects, and accelerated growth following failure to thrive. The laboratory results showed high insulin-like growth factor I (IGF-I) (standardised deviation scores ( +3.49) and prolactin levels (0.5 nmol/L), and magnetic resonance imaging identified a pituitary macroadenoma. Tumoral/hormonal control could not be achieved despite 3 neurosurgical procedures, each time with apparent total resection or with lanreotide or pasireotide. IGF-I levels decreased with the GH receptor antagonist pegvisomant. The loss of somatostatin receptor 5 was observed between the second and third tumor resection. In vitro, no effect on tumoral GH release by pasireotide (with/without cabergoline) was observed. Genetic analysis revealed a novel germline AIP mutation: p.Tyr202∗ (pathogenic; class 4).
Discussion: In vitro response of tumor tissue to somatostatin may better predict tumoral in vivo responses of somatostatin analogs than somatostatin receptor immunohistochemistry.
Conclusion: We identified a novel pathologic AIP mutation that was associated with incipient acrogigantism in an extremely young patient who had a complicated course of disease. Growth acceleration can be masked due to failure to thrive. Tumoral growth hormone release in vivo may be predicted with in vitro exposure to somatostatin receptor analogs, as it cannot be assumed that all AIP-mutated somatotropinomas respond well to pasireotide.
Keywords: AIP mutation; AIP, aryl hydrocarbon receptor–interacting protein; GH, growth hormone; IGF-I, insulin-like growth factor I; LAR, long-acting release; NR, normal range; SDS, standardised deviation scores; SSA, somatostatin analog; SSTR, somatostatin receptor; acromegaly; gigantism; macroadenoma; pituitary adenoma; somatotropinoma.
