Nonfunctional pituitary adenoma abutting chiasm

Introduction

The incidence of pituitary adenomas varies in many studies, in which radiographic studies have ranged from 1% to 40%, and postmortem studies have ranged from 1% to 35%. Based on a meta-analysis, the estimated prevalence of pituitary adenomas is 16.7%. With the widespread availability of imaging, the percent of incidental pituitary adenomas appears to be increasing. It is estimated that 30% of pituitary adenomas are discovered incidentally, in which the majority of these were macroadenomas that were clinically nonfunctional and extended into the suprasellar space with abutment of the optic chiasm. Although some advocate surgery for these lesions with optic chiasm involvement, others have advocated conservative management as the risks of pituitary apoplexy (0.6/100 patient-years), visual field deficits (0.6/100 patient-years), and endocrine dysfunction (0.8/100 patient-years) remain low. In this chapter, we present a case of a patient with a nonfunctional pituitary macroadenoma that was incidentally discovered without symptoms.

Example case

Chief complaint: headaches

History of present illness

A 59-year-old, right-handed woman with a history of diabetes and hypertension presented with headaches. Over the past 9 to 12 months, she complained of worsening migraines in terms of frequency and intensity. She underwent magnetic resonance imaging (MRI) that showed a pituitary lesion ( Fig. 57.1 ). Visual fields were full on formal visual field testing with ophthalmology.

Medications : Irbesartan, metformin.
Allergies : No known drug allergies.
Past medical and surgical history : Diabetes, hypertension, cholecystectomy, appendectomy.
Family history : No history of intracranial malignancies.
Social history : Store owner, no smoking or alcohol.
Physical examination : Awake, alert, oriented to person, place, and time; Cranial nerves II to XII intact with full visual fields to confrontation; No drift, moves all extremities with full strength.
Pituitary labs : Prolactin, thyroid stimulating hormone/T4, cortisol, insulin-like growth factor-1 all within normal limits.

	Lucas Alverne Freitas de Albuquerque, MD, Hospital Geral de Fortaleza, Ceara, Brazil	Arturo Ayala-Arcipreste, MD, Hospital Juarez de Mexico, Mexico City, Mexico	Edward R. Laws, MD, Daniel Donoho, MD, Brigham and Women’s Hospital, Boston, MA, United States	Nelson M. Oyesiku, MD, PhD, Joseph Quillin, MD, Emory University, Atlanta, GA, United States
Preoperative
Additional tests requested	CT maxillofacial Anesthesiology evaluation Endocrinology evaluation ENT evaluation	CT paranasal sinuses Endocrinology evaluation Ophthalmology evaluation (visual fields) Cardiology evaluation	FSH, LH, calcium MRI Cardiology evaluation	High-resolution T2 MRI Neuroophthalmology evaluation (visual fields, OCT) Endocrinology evaluation ENT evaluation Pregnancy test
Surgical approach selected	Endoscopic transnasal transsphenoidal	Endoscopic transnasal transsphenoidal	Endoscopic transnasal transsphenoidal	Endoscopic transnasal transsphenoidal
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, optic apparatus decompression, avoid future vision loss, improve headaches	Gross total resection, optic apparatus decompression, preservation of infundibulum and pituitary gland	Gross total resection, optic apparatus decompression, preservation of normal gland	Gross total resection
Perioperative
Positioning	Supine without pins	Supine without pins	Supine with skull clamps	Supine with skull clamps, 10-degree right rotation
Surgical equipment	Endoscope	EndoscopeSurgical navigation Microdoppler	Endoscope Microdoppler Microdebrider	0-degree endoscope Surgical navigation Ultrasonic aspirator Nasopore
Medications	None	Steroids	None	None
Anatomic considerations	Pituitary gland, internal carotid arteries, optic apparatus	Nasal structures, sphenoid sinus, sellar and parasellar regions, ICA, optic nerves and chiasm	ICA, pituitary gland, diaphragma sellae	Cavernous carotid arteries, optic nerves, ACOM
Complications feared with approach chosen	CSF leak, vascular injury	ICA injury, pituitary/infundibulum injury, vision loss, cavernous sinus injury	Visual loss, hypopituitarism, injury to infundibulum, CSF leak	ICA/ACA injury, diminished olfaction, optic nerve injury
Intraoperative
Anesthesia	General	General	General	General
Skin incision	None	None	None	None
Bone opening	Sphenoid osteotomy, removal of sellar bone	Sphenoid osteotomy and sphenoid sinus, floor of sella	Wide sphenoid osteotomy, removal of sellar bone	Right middle turbinate, wide sphenoid osteotomy, posterior ethmoidectomy, removal of sella from cavernous to cavernous sinus
Brain exposure	Sella	Sella	Sella	Sella cavernous sinus to cavernous sinus
Method of resection	Use of primarily 30-degree endoscope, lateralization of bilateral inferior and middle turbinates, nasoseptal flap on the left side, expose and open anterior wall of sphenoid sinus, large opening made in right posterior septum for binostril approach, identify sella, anterior wall of sella opened with high-speed drill or Kerrison rongeurs, open dura, tumor dissection, position nasoseptal flap, medialization and reposition of middle and inferior turbinates	Dislocation of bilateral middle and superior turbinates, identify sphenoid ostia and nasal septum, harvesting of nasoseptal flap bilaterally, expand both sphenoid ostum initially with Kerrison rongeur and drill, removal of mucosa in sphenoid sinus, removal of sellar bone, cauterize dura, open dura in cruciate fashion, use curettes to remove tumor in a clockwise fashion, use Doppler to localize ICA laterally, identify diaphragm, verify hemostasis using small pieces of gelfoam or Surgicel, use bone fragment to reconstruct sellar floor, use nasoseptal flap, apply fibrin glue, place nasal plugs	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	Lateralize inferior turbinates, right middle turbinate resection and free mucosal graft harvesting, partial resection of inferior aspect of superior turbinate, posterior septectomy, wide sphenoid sinusotomy and resection of rostrum, bilateral posterior ethmoidectomy, wide sphenoidotomy from cavernous to cavernous sinus, dural opening, extracapsular dissection of tumor, careful inspect for tumor and CSF leak, dural substitute inlay covered with free mucosal graft, Nasopore
Complication avoidance	Leave turbinates, binostril approach, nasoseptal flap	Unilateral nostril approach, systematic tumor resection, Doppler to localize ICA, bone for sellar floor reconstruction, nasoseptal flap for repair	Leave middle turbinates, wide sellar opening, extracapsular dissection, inspection for residual and CSF leaks	Wide sellar opening, extracapsular dissection, inspection for residual and CSF leaks
Postoperative
Admission	ICU	Floor	Floor	Floor
Postoperative complications feared	CSF leak, pituitary dysfunction	CSF leak, diabetes insipidus	Hypopituitarism, hyponatremia, diabetes insipidus, visual loss, ICA/cavernous sinus injury	HPA dysfunction (adrenal insufficiency, diabetes insipidus, SIADH), CSF leak
Follow-up testing	MRI 3 months after surgery Pituitary hormone evaluation 10 days and 3 months after surgery	Sodium and urine analyses for 72 hours after surgery CT within 24 hours after surgery MRI 5–6 weeks after surgery	Sodium and cortisol 7 days after surgery Endocrine panel 6 weeks after surgery MRI 3 months after surgery	Daily BMP, postoperative day two 8 a.m. cortisol MRI 3 months after surgery
Follow-up visits	7–10 days for hormonal evaluation 1, 3 months, 6 months, yearly after surgery	2 months after surgery 10 days after surgery with ENT and endocrinology	1 week after surgery for neuroendocrinology 3 months after surgery for neurosurgery	1 week after surgery for neuroendocrinology 2 weeks after surgery for ENT 6 weeks after surgery for neurosurgery