Growth hormone pituitary adenoma

Introduction

Growth hormone (GH)-secreting pituitary adenomas result in symptoms of acromegaly in adults and gigantism in children. It is caused by elevated levels of GHs and insulin-like growth factor-1 (IGF-1). Acromegaly is diagnosed with elevated IGF-1 and a failed oral glucose suppression test in which GH levels do not decrease to lower than 1 ng/mL with oral glucose adminsitration. Acromegaly is typically caused by a pituitary adenoma that secretes GH, which stimulates secretion of IGF-1 by the liver and leads to cardiovascular disease, musculoskeletal changes, diabetes, and risk of several malignancies, in which the risk of death is two-fold compared with the general population. Surgery is the first-line treatment for acromegaly. Biochemical control is achieved in 75% to 95% of patients with microadenomas but only 40% to 68% of patients with macroadenomas. The cure rates have decreased because of more stringent criteria of biochemical remission in recent years, and the median biochemical remission rate following surgery is approximately 50%. In this chapter, we present a case of a patient with a GH-secreting pituitary macroadenoma.

Example case

Chief complaint: facial and hand changes

History of present illness

A 36-year-old, right-handed man with no significant past medical history presented with facial and hand changes. His family noticed that his face had changed over the years. On questioning, his ring size had increased, as well as his shoe size from 10 to 12 over the past 2 years. He also complained of headaches and joint pain. He was seen by an endocrinologist who performed laboratory assessments and ordered magnetic resonance imaging (MRI) ( Fig. 60.1 ).

Medications : None.
Allergies : No known drug allergies.
Past medical and surgical history : None.
Family history : No history of intracranial malignancies.
Social history : Firefighter, no smoking or alcohol.
Physical examination : Awake, alert, oriented to person, place, and time; Cranial nerves II to XII intact, visual fields full to confrontation; No drift, moves all extremities with full strength.
Pituitary labs : IGF-1elevated, failed glucose suppression test; cortisol, prolactin, thyroid stimulating hormone/T4 all within normal limits.

	Luigi Maria Cavallo, MD, PhD, University of Naples Federico II, Naples, Italy	Edward R. Laws, MD, Daniel Donoho, MD, Brigham and Women’s Hospital, Boston, MA, United States	Eslam Mohsen Mahmoud Hussein, MBBS, MSc, Ain Shams University, Cairo, Egypt	Daniel M. Prevedello, MD, Ohio State University, Columbus, OH, United States
Preoperative
Additional tests requested	Sinus CT Laryngoscopy Colonoscopy Echocardiogram	Total testosterone, HgbA1c, serum Ca Sleep study if needed Hypertension, cardiac function evaluation	Ophthalmology evaluation (visual fields, fundus) Endocrinology evaluation ENT evaluation CT maxillofacial	Endocrinology evaluation CT maxillofacial
Surgical approach selected	Endoscopic endonasal transsphenoidal	Endoscopic endonasal transsphenoidal	Endoscopic endonasal transsphenoidal	Endoscopic endonasal transsellar
Other teams involved during surgery	ENT	ENT	ENT	ENT
Anatomic corridor	Transnasal transsphenoidal	Transnasal transsphenoidal	Transnasal transsphenoidal	Transnasal transsphenoidal
Goal of surgery	Gross total resection, preservation of normal pituitary gland	Gross total resection, biochemical cure, preservation of normal pituitary gland	Radical excision	Gross total resection
Perioperative
Positioning	Supine without pins	Supine with pins	Supine with left head tilt without pins	Supine without pins
Surgical equipment	Endoscope Microdoppler	Endoscope Microdoppler Microdebrider Ring curettes	Surgical navigation Endoscope Microdoppler	Surgical navigation Endoscope Microdebrider
Medications	Steroids	None	Steroids	None
Anatomic considerations	ICAs, clival recess	ICA, midline structures, tuberculum, clival recess, opticocarotid recess, Onodi cells if present	ICA, cavernous sinus, arachnoid of suprasellar cistern, optic nerves, pituitary stalk and gland	ICA, optic nerves, pituitary gland (including posterior pituitary), cavernous sinuses
Complications feared with approach chosen	ICA injury, CSF leak	Visual loss, hypopituitarism, carotid/cavernous sinus injury	ICA injury, vision loss, CSF leak	CSF leak, residual tumor, ICA injury, vision loss, diabetes insipidus
Intraoperative
Anesthesia	General	General	General	General
Skin incision	None	None	None	None
Bone opening	Sphenoid osteotomy, removal of sellar bone	Wide sphenoid osteotomy, removal of sellar bone	Wide sphenoid osteotomy, removal of sellar bone	Wide sphenoid osteotomy, removal of sellar bone
Brain exposure	Sella	Sella	Sella	Sella
Method of resection	Decongestion of nasal mucosa, lateralization of both middle turbinates, anterior sphenoidotomy, flattening of sphenoid septa, open sellar floor, dural incision, remove tumor	Lateralize bilateral middle turbinates, posterior septectomy with preservation of rescue flaps, exposure of sphenoid ostia, removal of sphenoid face out to lateral recesses and rostral aspect of sphenoid, removal of sphenoid sinus septations and mucosa, remove sellar face, open dura, resect tumor extracapsularly if possible, evaluate for CSF leak, abdominal fat if leak present, reconstruct sellar face with medpore/septal cartilage or bone, medialize middle turbinates	Mucosa incised in midline, vomer removed, insertion of nasal speculum with keel used as landmark, bone removed between sphenoid ostia, mucosa removed, sphenoid floor is drilled if thick, dura opened in cruciate fashion, tumor removed with ring curettes, Valsalva to facilitate tumor descent, if CSF leak, the sella is packed with abdominal fat and lumbar drain is inserted, nasal packs for 24–48 hours	Midline turbinates lateralized, bilateral rescue flaps raised, sphenoid rostrum exposed and drilled, anterior sphenoidotomy, septations are drilled, face of sella is drilled, dural opening with feather blade, plane between tumor and gland identified, extracapsular dissection, inspect cavity with 45-degree endoscope for residual, hydrogen peroxide to cavity, synthetic dural for replacement, splints placed bilaterally
Complication avoidance	Leave middle turbinates, wide sellar opening, cognizant of spheno-palatine branches	Leave middle turbinates, wide sellar opening, extracapsular dissection, inspection for residual and CSF leaks	Use keel as midline landmark, Valsalva to facilitate tumor descent, CSF leak repaired with abdominal fat and lumbar drain	Extracapsular dissection, hydrogen peroxide
Postoperative
Admission	Floor	Floor	Intermediate care	Intermediate care
Postoperative complications feared	Nasal bleeding, CSF leak	Hypopituitarism, hyponatremia, visual loss, arterial injury, airway issues	Diabetes insipidus, CSF leak, vascular injury, visual deficit	Diabetes insipidus, CSF leak
Follow-up testing	Growth hormones 1 and 3 days after surgery with goal <1 Sodium and electrolytes 10 days after surgery MRI 3 months after surgery	Growth hormone levels until <1 while admitted Sodium and cortisol 1 week after surgery Full endocrine labs at 6 weeks after surgery MRI 3 months after surgery	Growth hormone levels for 3 days Full hormonal panel and electrolytes Visual acuity and field testing MRI within 36 hours after surgery	Growth hormone level before, during, end of resection and postoperative day 1 CT after surgery Sodium and specific gravity every 6 hours MRI 3 months after surgery
Follow-up visits	10 days after surgery	1 week after surgery for neuroendocrinology 3 months after surgery for neurosurgery	Daily after surgery for 1 week for ENT 7 days after surgery for neurosurgery	6 weeks with neurosurgery 7 days with ENT and endocrinology
Adjuvant therapies recommended	Medical treatment if disease not controlled, consider radiation or repeat surgery upon failure	Somatostatin analogues at 6–12 months	Somatostatins or SRS	Second surgery if residual, somatostatin if nonsurgical