Giant Prolactinoma Presenting With Facial Nerve Palsy and Hemiparesis

Aleksandra Sliwinska; Fatima Jalil; Lori De La Portilla; Michael Baldwin; Joseph Lorenzo; Ketan R. Bulsara; Faryal S. Mirza


J Endo Soc. 2021;5(9) 

In This Article

Case Description

A 25-year-old previously healthy, dominant left-hand man presented to the walk-in clinic for an evaluation of stroke with longstanding left-sided facial asymmetry, and new weakness of the left arm and leg.

His symptoms started several months prior to the presentation when he returned from a summer camp and noticed a left-sided facial droop. He presented to his primary care office, where he tested negative for Lyme disease and was thought to have Bell's palsy. Six months later, he noted a new weakness in the left upper and lower extremity, which affected his gait. Due to worsening symptoms and concern about a possible stroke, a magnetic resonance imaging (MRI) of the brain was ordered, and once the mass was identified, he was advised to report to the emergency department for admission.

At the time of admission, his symptoms included facial asymmetry and left-sided weakness. He reported occasional nausea and vomiting but denied having headaches, visual changes, loss of sensation, rhinorrhea, or ear discharge. He did report unknowingly bumping into things in the last few weeks. He noted a weight gain of 50 pounds in the last 6 months due to increased appetite. History was also positive for decreased libido and loss of morning erections. Family history was negative for brain tumors.

On physical examination, the patient was alert and oriented. He demonstrated right eye proptosis and loss of nasolabial fold on the left. He was able to close his left eye, forehead, and eyebrow movements were preserved consistent with central facial nerve palsy. Pupils were round, equal, reactive, and extraocular movements were intact. The ophthalmic examination showed normal fundus, unremarkable visual acuity with left-sided temporal visual field deficit. Left upper and lower extremity weakness was noted. Sensory testing was normal. There was no ataxia or dysmetria, and the gait was normal. Galactorrhea or gynecomastia was not appreciated, and testicular size was normal.

MRI of the brain was performed, and results were consistent with an enormous extra-axial multilobulated mass arising in the region of the right cavernous sinus invaginating deep into the base of the right cerebral hemisphere and producing a mass effect on the pons, right-sided midbrain, right temporal lobe, and right basal nuclei. In overall dimensions, the mass measured 60 mm × 55 mm × 75 mm (anteroposterior, transverse, and craniocaudal, respectively) without ischemic findings (Figure 1). The tumor was enhanced homogeneously except for cystic and hemorrhagic areas. The patient underwent a computed tomography angiogram, which demonstrated displacement of the right internal carotid artery and anterior displacement of the right middle and anterior cerebral artery. There was no significant vascular stenosis, and the mass demonstrated moderate vascularity. Magnetic resonance venography confirmed the invasion of cavernous sinuses and the right petrosal sinus without thrombosis.

Figure 1.

Initial MRI of the brain: sagittal T1 precontrast (1), sagittal T1 postcontrast (2), and coronal T1 postcontrast view (3) demonstrating enormous sellar mass.

Initial laboratory testing revealed a serum PRL level of 13 580 ng/mL (ref: 2.64–13.13 ng/mL). Further workup demonstrated a thyroid stimulating hormone of 1.71 μU/mL (ref: 0.35–4.94 μU/mL) with a free thyroxine of 0.6 ng/dL (ref: 0.61–1.82 ng/dL), a morning cortisol of 4.8 μg/dL (ref: 7–23 μg/dL), an adrenocorticotropic hormone of 18 pg/mL (ref: 7–69 pg/mL), an insulin-like growth factor 1 of 112 ng/mL (ref: 99–283 ng/mL), and a growth hormone level of <0.05 ng/mL (ref: 0.05–3.00 ng/mL). A cosyntropin stimulation test demonstrated a normal cortisol levels at 30 and 60 minutes. Gonadal panel showed a luteinizing hormone of 0.31 mIU/mL (ref: 1.24–8.62 mIU/mL), a follicle stimulating hormone of 0.9 mIU/mL (ref: 1.27–19.26 mIU/mL), a sex hormone binding globulin of 15 nmol/L (ref: 11–80 nmol/L), and a testosterone level of 42 ng/dL (ref: 300–1080 ng/dL) with free testosterone of 10 pg/mL (ref: 47–224 pg/mL), which was consistent with hypogonadotropic hypogonadism. Hemoglobin A1c was 5.6%. His basic metabolic panel revealed only mild hyponatremia with a serum sodium of 133 mmol/L.

The patient was diagnosed with a giant prolactinoma and was managed by a multidisciplinary team, including endocrinology, ophthalmology, and neurosurgery. Given his very high PRL level, he was started on high-dose CAB, 0.5 mg daily, with close monitoring by neurosurgery and ophthalmology. After being on CAB 0.5 mg daily for a week, there was a 74% reduction in his serum PRL level to 3515 ng/mL. Repeat MRI showed stability of the pituitary mass after 1 week and CAB dose was decreased to every other day after 2 weeks of the treatment as the PRL level began to decline further. Repeat MRI of the brain 6 weeks after initiation of dopamine agonist therapy, showed a significant reduction (57%) in the tumor size to 60 mm × 38 mm × 47 mm, and volume (decreased from 247 cm3 to 107 cm3) (volume calculated using equation V = abc using the 3-dimensional MRI measurements [anteroposterior, transverse, and craniocaudal]. The left-sided weakness and facial asymmetry resolved a few months after treatment initiation, followed by resolution of the visual field deficits. At the 7-month follow-up visit, the patient reported full resolution of symptoms with normal neurological and visual function. He resumed normal erections, although testosterone level was still below normal. The prolactinoma size decreased to 63 mm × 13 mm × 38 mm (31 cm3), corresponding to an 87.5% total volume reduction after 12 months. The gonadotropic axis remained suppressed, although consistent recovery was noted, with total testosterone levels of 185 ng/dL (from 42 ng/dL) and free testosterone of 42 ng/dL (from 18 ng/dL) at his 15-month follow-up (Figure 2). Simultaneously, follow-up MRI revealed approximately 91% total volume mass reduction since the diagnosis, with 57 mm × 11 mm × 35 mm measurements (Figure 3). Subsequent labs at 22 months showed further improvement of total testosterone to 214 ng/dL and free testosterone of 45 ng/dL, while PRL levels decreased to 649 ng/mL on continued dopamine agonist therapy (CAB 0.5 mg every other day) (Figure 2).

Figure 2.

Trend line of prolactin (nanogram/millimeter, ng/mL) and total testosterone (nanogram/deciliter, ng/dL) level from the diagnosis until 22-month follow-up.

Figure 3.

MRI of the brain at 15-month follow-up: sagittal T1 precontrast (1), sagittal T1 postcontrast (2), and coronal T1 postcontrast view (3) demonstrating significant reduction in the size of the tumor.