Nonfunctional pituitary adenoma with vision loss

Introduction

Pituitary adenomas have an estimated prevalence of 10%, in which they are considered the fourth most common intracranial tumor after gliomas, meningiomas, and schwannomas. It is estimated that approximately 50% of pituitary adenomas are clinically nonfunctional adenomas, in which they either secrete no hormones or clinically silent hormones. These nonfunctional pituitary macroadenomas can either be incidental or cause significant hypothalamic or pituitary dysfunction, vision loss, ophthalmoplegia, and/or symptoms of mass effect (i.e., headaches). The long-term control rate following surgery is 70% to 80% in several studies, in which smaller tumor size and lack of cavernous sinus invasion are associated with higher chances of tumor control. In addition, surgery can lead to improvement in one or more hormonal abnormalities in 15% to 50% of patients, but can induce loss of one or more pituitary hormones in 2% to 15% of patients. In this chapter, we present a case of a patient with a nonfunctional pituitary macroadenoma with bitemporal visual field loss.

Example case

Chief complaint: amenorrhea

History of present illness

A 36-year-old, right-handed woman with no significant past medical history presented with amenorrhea. She stated she had not had her menstrual cycle for almost 1 year. She was seen by her obstetrician who ordered a prolactin test and it was elevated. This led to imaging ( Fig. 56.1 ).

Medications : None.
Allergies : No known drug allergies.
Past medical and surgical history : None.
Family history : No history of intracranial malignancies.
Social history : Accountant, no smoking or alcohol.
Physical examination : Awake, alert, oriented to person, place, and time; Cranial nerves II to XII intact, except bitemporal hemianopsia to confrontation; No drift, moves all extremities with full strength.
Pituitary labs : Prolactin 75 ng/ml (even after dilution), thyroid-stimulating hormone/T4, cortisol, insulin-like growth factor-1 all within normal limits.

	Peter Bullock, FRCS, MRCP, London Clinic, London, England	Paul A. Gardner, MD, University of Pittsburgh, Pittsburgh, PA, United States	Nelson M. Oyesiku, MD, PhD, Joseph Quillin, MD, Emory University, Atlanta, GA, United States	Rodrigo Ramos-Zúñiga, MD, PhD, University of Guadalajara, Guadalajara, Jalisco, Mexico
Preoperative
Additional tests requested	MR angiography CT Neuroendocrinology evaluation Neuroophthalmology evaluation	CT angiogram Neuroendocrinology evaluation (a.m. cortisol) Neuroophthalmology evaluation (visual fields) ENT evaluation	High-resolution T2 MRI Neuroophthalmology evaluation (visual fields, OCT) Neuroendocrinology evaluation ENT evaluation Pregnancy test	MR angiography Neuroophthalmology evaluation (visual fields)
Surgical approach selected	Endoscopic endonasal transsphenoidal	Endoscopic endonasal transsphenoidal and transtubercular	Endoscopic endonasal transsphenoidal and transtubercular with lumbar drain	Microsurgical endonasal transsphenoidal
Other teams involved during surgery	ENT	ENT	ENT	ENT
Anatomic corridor	Endonasal transsphenoidal	Endonasal transsphenoidal and transtubercular	Endonasal transsphenoidal and transtubercular	Endonasal transsphenoidal
Goal of surgery	Extensive resection, preservation of pituitary function, visual improvement	Gross total resection, preservation of pituitary function, visual recovery	Gross total resection	Tumor decompression, decompression of optic apparatus, control of prolactin production
Perioperative
Positioning	Supine with pins, 15 degree left rotation	Supine with skull pins, right rotation and slight extension with head/back elevated	Supine with skull pins, 10-degree right rotation	Supine with slight left rotation without skull pins
Surgical equipment	Surgical navigation Endoscopes	IOM (SSEP) Surgical navigation Endoscopes Cranial Doppler	Lumbar drain Surgical navigation 0- and 30-degree endoscopes Cranial Doppler Ultrasonic aspirator	Fluoroscopy Surgical microscope Sellar floor implant
Medications	Steroids Tranexamic acid	Steroids	None	Steroids
Anatomic considerations	Sella, optic nerves, ICA	Parasellar and paraclival ICA, opticocarotid recesses, sphenoid limbus, cavernous sinus walls, pituitary gland	Cavernous carotid arteries, optic nerves, ACOM, lamina terminalis, hypothalamus	Sphenoid sinus, sellar floor, ICA, diaphragma sella
Complications feared with approach chosen	Hypopituitarism, vision loss, CSF leak, ICA injury, meningitis	Hypopituitarism, vision loss, CSF leak, carotid injury	Retraction injury to frontal and temporal lobes, neurovascular injury to optic nerve, ICA, basilar artery, hypothalamus	Injury to ICA or pterygopalatine arteries, optic nerve injury, pituitary/pituitary stalk injury
Intraoperative
Anesthesia	General	General	General	General
Bone opening	Anterior wall of sphenoid sinus, sella	+/– right middle turbinate, partial right superior turbinate, anterior wall of sphenoid sinus, posterior ethmoidectomy, sella from cavernous to cavernous, tuberculum, medial and lateral opticocarotid recess	+/– right middle turbinate, wide sphenoid osteotomy, posterior ethmoidectomy, removal of sella from cavernous to cavernous sinus, tuberculum	Anterior wall of sphenoid sinus, sellar floor
Brain exposure	Sella	Sella complete right cavernous sinus and medial left cavernous sinus, tuberculum removal	Sella cavernous to cavernous sinus and tuberculum removal	Sella
Method of resection	ENT starts the approach, wide sphenoidotomy and mobilizing nasoseptal flap, bone removed from sellar face, identification of ICA/optic canals and confirmed with navigation, dura opened with diamond knife, develop plane of pseudocapsule with dissector starting at apex and working circumferentially around the tumor, deliver tumor likely in piecemeal given the size with large right-angle ring curette starting at floor and moving superiorly, remove lateral portions of tumor before diaphragm descends, observe for descent of diaphragma sella, inspection with 30-and 45-degree angled scopes, multi-layer closure with nasoseptal flap in gasket seal like fashion, place lumbar drain for 72 hours if there is a concern for CSF leak	Lateralize or resect right middle turbinate, partial resection of right superior turbinate to expose sphenoid ostium, harvest left nasoseptal flap, lateralize left middle turbinate, posterior ethmoidectomy, nasal protective sleeves, drill down sphenoid rostrum and expose lateral recess, strip sphenoid mucosa, remove bone over sella and expose entire right medial cavernous sinus and medial left cavernous sinus and up to sphenoid limbus and medial opticocarotid recesses, dura opened in an inverted V shape, tumor resected with two suctions and pituitary rongeur to peel tumor capsule, dissection continues laterally up the cavernous walls, resection superiorly with angled endoscopes into third ventricle, inspect cavity, if high flow leak use collagen inlay and nasoseptal flap, nasal packing	Lateralize inferior turbinates, +/– resection of right middle turbinate, partial resection of inferior aspect of superior turbinate, posterior septectomy, wide sphenoid sinus opening, resection of sphenoid rostrum/bilateral posterior ethmoid air cells, raise large right Hadad nasoseptal flap, removal of sellar face from cavernous to cavernous sinus, drill out clival recess, thin sphenoid tuberculum past limbus dural fold and reflect bone away, open dura, extracapsular dissection, assessment for residual tumor nests and CSF leak, retrieval of nasoseptal flap, Nasopore	Local anesthetic and local vasopressors into nasal septum and turbinates, nasoseptal flap dissection, displacement of septum, location of sphenoid ostia, resection of anterior wall of sphenoid sinus, anatomic localization of sellar floor and carotid prominences with direction under microscopic vision and fluoroscopy, drilling of sellar floor and removal with rongeurs, tumor micropuncture to confirm absence of cavernous sinus bleeding, intratumoral debulking, tumor aspiration and curettage, capsular resection with preservation of diaphragma, repair of sellar floor with chitosan, fat graft in sphenoid sinus, nasoseptal flap placement, intranasal ventilation tubes
Complication avoidance	Wide bony opening, removal of tumor floor and working upward, inspection with angled scopes, nasoseptal flap for dural reconstruction	Harvesting nasal septal flap, wide bony opening, exposure of right cavernous sinus, two suction technique, identify tumor capsule, inspection with angled scope	Harvesting nasal septal flap, wide sellar opening, extracapsular dissection, close attention to right cavernous sinus, inspection with various scopes for residual and CSF leaks	Harvesting nasal septal flap, fluoroscopy to guide localization, micropuncture, sphenoid sinus fat and nasoseptal flap, lumbar drain if needed for 24 hours
Postoperative
Admission	High dependency unit	Intermediate care	Floor	ICU
Postoperative complications feared	CSF leak, hypopituitarism, diabetes insipidus	CSF leak, hypopituitarism, diabetes insipidus	HPA dysfunction (adrenal insufficiency, diabetes insipidus, SIADH), CSF leak	Injury to pterygopalatine and ICA, optic nerve damage, diabetes insipidus, adrenal insufficiency
Follow-up testing	Maintain strict fluid balance Vision checked every 4 hours MRI within 24 hours of surgery and 3 months after surgery	8 a.m. cortisol and prolactin 2 days after surgery Daily electrolytes and strict fluid assessment CT immediately after surgery if large CSF leak MRI 3 months after surgery	Daily BMP, postoperative day two 8 a.m. cortisol, LD for 3 days MRI 3 months after surgery	CT within 24 hours after surgery MRI within 72 hours after surgery Sodium checks and urine volumes Neuroendocrine evaluation 24 hours after surgery
Follow-up visits	3 months after surgery with neurosurgery 1 week after surgery with ENT 2 weeks after surgery with endocrinology	1 week after surgery for neurosurgery and ENT 2 weeks after surgery for endocrinology and ophthalmology	1 week after surgery for neuroendocrinology 2 weeks after surgery for ENT 6 weeks after surgery for neurosurgery	4 weeks after surgery