When a 'Benign' Growth Causes Visual Field Loss

This case shows the importance of timely referral for neurological consult and treatment. It helped prevent further visual loss in this patient.

Sherry J. Bass, O.D.
Contributing Editor

A 23-year-old overweight black female presented complaining that she could not see well out of her new glasses. She was examined elsewhere three months earlier and prescribed the glasses, but said that doctor didn’t mention any other problems to her.

The first doctor at our clinic who examined the patient noted the presence of papilledema, and referred the patient to me. Upon further questioning, she reported occasional frontal headaches for the past 15 months. She believed these mild headaches were stress-related, and said they were alleviated by over-the-counter nonsteroidal anti-inflammatory drugs. Her ocular and health history were otherwise unremarkable except for her weight gain, which she said was recent.

Diagnostic Data
Best corrected visual acuities were 20/30 in both eyes. External examination revealed normal pupils, anterior segment structures and color vision. Intraocular pressure was 24mm Hg in each eye.

Funduscopy revealed bilateral optic disc edema. The edema made it impossible to determine cup-to-disc ratios. All other fundus findings were normal.
B-scan ultrasonography did not reveal any disc drusen or orbital abnormalities. Visual field testing revealed a relative superior field defect in the right eye and a dense superior hemianopic defect in the left eye.

Treatment and follow-up
The patient’s history of headaches, her weight, the optic nerve head appearance and the visual field defects all made me suspect chronic pseudotumor cerebri. I referred the patient for a neurological consult and neuroimaging.

The history taken during the neurological evaluation revealed an additional symptom: The patient’s menstrual period had ceased for the past five months.
Neurological examination revealed a slightly unsteady gait with increased reflexes throughout and bilateral Babinski’s sign (extension of the large toe with fanning of the small toes upon stimulation of the foot). The patient also exhibited mild deficits in graphesthesia (ability to recognize figures written on the skin), joint position sense in the right hand and past pointing on finger-to-nose testing.

Magnetic resonance imaging revealed a large cystic midline cerebellar tumor. Pathological testing showed this to be a hemangioblastoma. The MRI also revealed hydrocephalus with a herniated third ventricle and an empty sella turcica with no evidence of a pituitary gland. The cyst and the tumor were surgically resected without complication.




2, 3: Elevated, edematous optic nerve heads in the right eye (top left) and left eye (top right).4, 5: Six months post-op, the optic nerve head edema has almost resolved, but temporal pallor is evident. This is greater in the left eye(bottom right) than the right

.

Six months post-op, the patient reported no further headaches and achieved better balance while walking. Her menstrual periods had resumed.
Best corrected visual acuity was now 20/25 in both eyes. Ophthalmoscopy revealed resolving disc edema with temporal pallor. This was greater in the left eye. The visual field defect resolved in the right eye, but a residual relative superior defect was still evident in the left. IOPs remained mildly elevated, but the optic nerve head cupping did not appear to be glaucomatous in either eye.

Despite the improved visual acuity and visual fields, nerve fiber layer analysis revealed significant attenuation. This, too, was greater in the left eye. These results suggest permanent damage from the papilledema.

The neurologist continues to monitor this patient for recurrence, and she must have a repeat MRI annually. I continue to monitor her visual status annually.

Discussion
Intracranial hemangioblastoma, or Lindau’s disease, is a rare benign neoplasm that arises from vascular endothelium. It accounts for about 2-3 percent of all intracranial tumors.1 When associated with retinal and/or optic nerve hemangioblastomas, it’s called von Hippel-Lindau disease (VHL), a genetic disorder mapped to chromosome 3.1

Hemangioblastomas most often occur in the cerebellum, brain stem or spinal region. These tumors exist as a neural nodule with cyst in the cerebellum, but are solid in the spinal and brain stem region.1

Intracranial hemangioblastomas also may be associated with renal cell carcinoma, pancreatic cysts, and with or without pheochromocytoma (VHL type 2 and VHL type 1, respectively).2 This patient appears to have an isolated cerebellar hemangioblastoma. She did not demonstrate any retinal or optic nerve vascular anomalies, nor did she have renal or pancreatic abnormalities.

This young woman exhibited the signs and symptoms of chronically elevated intracranial pressure. Given her sex, age and weight, pseudotumor cerebri (PTC) was a likely diagnosis. However, PTC is a diagnosis of exclusion; you must refer the patient for a neurological exam and imaging to rule out other serious conditions.
The neurological exam did not support a diagnosis of PTC in this patient. An unsteady gait and past pointing on finger-to-nose touch suggested cerebellar involvement.

The absence of menses suggested a pituitary abnormality. Pressure from the herniated third ventrical most likely resulted in a prolapsed pituitary gland. Surgical excision of the tumor eliminated its compressive effect on the surrounding structures, restoring normal pituitary function.

Figure 6	Figure 7

6. Visual fields reveal relative superior field loss, right eye and dense superior hemianopic defect left eye. 7. Visual fields six months post-op demonstrate improvement in both eyes, with a relative field defect remaining in the left eye.

Other deficits noted during the neurological exam, such as loss of joint position sense and positive Babinski’s sign, also supported a diagnosis of cortico-spinal disease. Increased intracranial pressure led to the papilledema, and increased pressure on the inferior fibers of the visual pathway most likely caused the dense superior field defects.

Treatment of hemangioblastoma consists of surgical resection, as in this case. Stereotactic radiosurgery and gamma knife radiation also have been successful in select cases, either as the sole method of treatment or as an adjuvant to surgical resection if there’s a recurrence.3,4 Spinal cord and brain stem hemangioblastomas are more difficult to treat than the cerebellar tumors.1

If undetected and untreated these tumors not only threaten vision, but can be life threatening as well. Even though this patient’s subjective symptoms and ophthalmic testing results improved, she still suffered permanent damage, as shown by GDx nerve fiber layer analysis and the visual field defect.

We can’t predict if and when there will be a recurrence, so we must continue to monitor the patient. In one retrospective study of 41 patients, three patients had recurrences with a mean time interval of 5.7 years.5

This patient’s presenting signs and symptoms pointed to a likely diagnosis of pseudotumor cerebri, which also requires treatment. However, this case emphasizes the importance of obtaining a neurological consult to rule out other serious conditions that may masquerade as PTC. This case also shows that significant hydrocephalus can exist even with just a mild symptom of headache.

As primary eye care providers, we can make a difference in the outcome of these cases by making a timely referral to a neurologist and by helping to monitor post-op patients for a recurrence.

Dr. Bass is a professor at the State University of New York College of Optometry and director of its residency program in ocular disease.

1.	Matsumoto K, Kannuki S. Hemangioblastoma and von Hippel-Lindau disease. Nippon Rinsho-Jap J Clin Med 1995;53(11):2,672-7.
2.	Glavac D, Neumann HP, Wittke C, et al. Mutations in the VHL tumor suppressor gene and associated lesions in families with von Hippel-Lindau disease from central Europe. Human Genetics 1996;98(3):271-80.
3.	Patrice SJ, Sneed PK, Flickinger JC, et al. Radiosurgery for hemangioblastoma: results of a multi-institutional experience. Intl J Rad Oncol, Biol, Physics 1996;35(3):493-9.
4.	Niemela M, Lim YJ, Soderman M, et al. Gamma knife radiosurgery in 11 hemangioblastomas. J Neurosurg 1996;85(4):591-6.
5.	Zimmermann M, Seifert V, Schreyer F, et al. Hemangioblastoma: description of a disease picture and report of 41 cases. Zentralblatt fur Neurochiurgie 1997;58(1):1-6.
6.	Miller NR (ed). Walsh and Hoyt’s Clinical Neuro-Ophthalmology. 4th ed. Baltimore: Waverly Press, Inc., 1982:200.
7.	Miller NR, Newman NJ (eds ). Walsh and Hoyt’s Clinical Neuro-Ophthalmology. 5th ed., vol. 3. Baltimore: Williams and Wilkins Inc., 1998:3,927.