IMPE Abstracts

Introduction: Pituitary gigantism is a rare disorder resulting from excessive growth hormone (GH) production in children. Somatostatin is a physiological inhibitor of GH secretion, and somatostatin analogs have been used in medical treatment of acromegaly in adults. Here we present a case of pasireotide use for management of pituitary gigantism not amenable to complete surgical resection.

Case: A 15yo Ukrainian refugee female was referred for concerns of gigantism and primary amenorrhea. Patient and mother had concerns of rapid growth. She measured 6’4”, reporting height gain of 3” in past 6 months. Rapid growth started at age 13 and accompanied with joint pains, nose enlargement and hand swelling. She experienced thelarche and pubarche but no menarche. She endorsed transient vision changes but denied peripheral vision impairment. She reported headaches and fatigue. Mother is 5’4”, father’s height not available. No growth charts were available. Bone age was delayed by 2 years. Initial laboratory findings were significant for very elevated IGF-1 levels, Z-score of +6.3, GH above the limit of detection, and elevated alkaline phosphatase. Further pituitary work up was completed at initial endocrine visit (Table 1). Patient was started on levothyroxine and had menarche shortly after. MRI of brain revealed a pituitary macroadenoma measuring 2.4x2.9x1.6cm with significant extension into bilateral cavernous sinuses and bilateral encapsulation of the internal carotids. She was deemed a candidate for urgent surgical intervention with adjuvant medical therapy afterwards. Patient underwent endonasal endoscopic tumor debulking. Postoperatively, pituitary gland and stalk were preserved. Final pathology showed somatomammotroph pituitary adenoma which expressed GH and variable prolactin. Pit1 was expressed in tumor cell nuclei. Patient was started on pasireotide 40mg monthly 2 weeks after debulking.

Conclusion: Pituitary gigantism is an extraordinarily rare but serious condition in childhood. First generation somatostatin receptor ligands (SRL) have been considered first line medical treatment. Pasireotide is a relatively new second generation SRL that binds to multiple somatostatin receptors. Decision to start pasireotide was based on this patient’s young age, bone age, tumor size and invasiveness, imaging and very high levels of GH. Follow up after 2 doses so far is showing decrease in GH secretion.