Reduced vision: Craniopharyngeal neuroma in children

Reduced vision: Craniopharyngeal neuroma in children. Reduced vision is a common symptom of craniopharyngeal neuroma in children. SickKids Hospital in North America: Long-term vision follow-up report of children with craniopharyngioma. 

Pediatric craniopharyngioma is a central nervous system tumor. The age of onset presents a bimodal distribution, one peak is in children aged 5 and 14 years, and the second peak is in adults aged 65 and 74 years. In children, craniopharyngiomas account for about 5%-10% of all intracranial tumors. Although histologically benign, these tumors are locally aggressive and can cause significant morbidity and mortality.

Most patients are left with various combinations of visual impairment, endocrine disease, hypothalamic dysfunction, cerebrovascular disease and neurological dysfunction due to the tumor itself or secondary treatment. Since craniopharyngiomas are close to the optic nerve and chiasma, one of its most common effects is vision loss. Therefore, visual function has always been an important clinical sign that can help diagnose craniopharyngiomas, guide treatment decisions, and monitor recurrence.

Long-term vision prognosis is also an important issue affecting children and their families. There have been several cohort studies on pediatric craniopharyngiomas, but long-term data and detailed visual results need to be updated. The purpose of this study is to report the rate of vision loss and long-term vision results for a group of children with craniopharyngiomas.

This study is designed as a retrospective single-center case series study. The research object was determined through the database of all patients with craniopharyngioma in the Toronto Children’s Hospital where Professor James T. Ruka of INC was located in the past 20 years (1997 to 2017). A detailed visual acuity assessment (visual acuity, visual field and fundus dilation examination) is required before treatment, and a follow-up visual acuity assessment should be performed at least 1 year after diagnosis. The last follow-up was defined as the last detailed visual acuity assessment in the record, and the follow-up time was defined as the time from diagnosis to the last visual acuity assessment.

Each subject was reviewed in detail to determine baseline characteristics. Tumor components are classified into cystic/predominantly cystic (more than 60% cystic) or solid/predominantly cystic (less than 60% cystic). Tumor size is divided into two categories: larger than 4 cm and smaller than 4 cm. The main outcome measure is the decrease in vision from appearance to final follow-up. The risk factors related to vision loss are also analyzed.

Vision loss is defined as a shift in the visual function of one or both eyes from a higher category to a lower category. For analysis purposes, the visual acuity results are divided into ordered scales, which are divided into three categories according to the standard definition used in the United States (1) normal vision, (2) visually impaired (3) blindness.

In this study, we reported the long-term vision results of 59 children with craniopharyngiomas.

Although the common symptom is headache, neuro-ophthalmological manifestations are also common at the time of diagnosis. In view of the high incidence of headache in the general population, related findings such as missing visual field, diplopia, and optic nerve edema may be key indicators of severe intracranial disease.

Other studies have also found that children with craniopharyngiomas have a high proportion of visual dysfunction (55-75%), which emphasizes the importance of assessing visual function when severe intracranial lesions are suspected. After diagnosis, the risk of long-term visual impairment is an important issue for children with craniopharyngiomas and their families. The main result of this study was a significant loss of visual function from presentation to final follow-up.

At Toronto Children’s Hospital, vision and visual field tests are performed every 16 months to monitor vision function. If there is a change in vision or visual field, recheck the vision within 1-2 weeks to confirm that the change in vision is real. It is important to realize that between the two tests, collaboration ability and concentration can fluctuate greatly, especially in young children.

In addition, cognitive deficits and behavioral problems are not uncommon in this group and can affect the reliability of visual tests. Therefore, it is important to perform visual tests repeatedly to confirm any changes in visual function. Among patients who were not blind at the time of diagnosis, we found that younger age at diagnosis, optic nerve edema, and tumor recurrence were significantly associated with long-term vision loss. The risk factors for vision loss in children with craniopharyngiomas have not been reported before, although two previous studies have found that younger age at diagnosis is a risk factor for ultimately poor vision.

In terms of the time to vision loss, a large part of it occurs in the early stage, and about half of the cases occur in the first 4 months after diagnosis. Although the risk of vision loss was reduced in the first few months, there was a case of a patient with a significant loss of vision 8 years after diagnosis, which highlights the importance of long-term follow-up for all children with craniopharyngiomas. When a child with a known craniopharyngioma has severe vision deterioration, it is important to find the root cause in time, because treatment can effectively restore vision.

Among the 8 patients with acute vision loss due to the growth of cystic tumors, 3 patients recovered completely after treatment, and 3 patients recovered partially. It should also be noted that in these two cases of deterioration of vision due to drug leakage (bleomycin and interferon), vision was completely restored over time. In this study, the total burden of visual impairment was high because at the last follow-up, 58% of patients had evidence of visual impairment (one or both eyes).

Three studies published between 2005 and 2012 show that the incidence of visual impairment is similar, about 50%, although there are significant differences in the definition of visual impairment. In contrast, a study published in 1988 stated that 17 of 22 children (77%) had permanent vision loss. This may be due to more and more people using minimally invasive surgical techniques for individualized treatment of craniopharyngiomas to balance tumor control and quality of life. At SickKids, patients are taken care of by a multidisciplinary team who conduct a series of neuroimaging and visual assessments to strive for a better prognosis for the children.

Unilateral visual impairment is a sensitive indicator of visual system damage, while binocular visual impairment has a more significant impact on the quality of life, including an increase in mortality. Therefore, the long-term visual function of better eyes (ie, binocular visual impairment) is a key prognostic factor affecting the quality of life.

In this cohort, at the final follow-up, 63% of patients had at least one eye with normal vision (that is, the remaining 37% had some degree of binocular vision impairment). However, only 10% of patients are legally blind. The prognosis of children with severe binocular vision loss at the time of diagnosis is poor, because in this cohort, at the final follow-up, all four patients with legal blindness in both eyes were the same.

However, of the other 55 patients, only 2% (4%) became double-blind at the final follow-up. Some existing studies have reported similar blindness rates between 8-28%. Parents are often relieved to learn that most children with craniopharyngiomas are not blind in the law. For children with obvious binocular vision loss, it is helpful to receive low vision services as soon as possible to obtain available resources and optimize functions.

(source:internet, reference only)

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