Correspondence granular-nodular, and calcific that are seen with parenchymal cysts.6 This form of neurocysticercosis constitutes a hydropic change as degenerated cyst wall shows a rapid hyalinization and enlargement that leads to large or even giant vesicles usually devoid of a scolex. The cysts attain large size because the growth is not stopped by pressure effects exerted by brain parenchyma.7 MRI has been shown to be modality of choice for diagnosing neurocysticercosis,8 but histopathologic examination might be required in a few cases for confirmation.9 Differential diagnosis for multiple cysts includes cryptococcal cysts, with histopathology being confirmatory.10 Patients with neurocysticercosis mainly present with seizures/epilepsy (79%), severe headache (38%), focal deficits (16%), and signs of raised intracranial pressure (12%).11 Although visual loss is not a common cause of presentation in neurocysticercosis, it is a common feature occurring secondary to optic neuropathy resulting from papilledema. Other causes of visual loss include chiasmal involvement from inflammation or compression by large cysts and retrochiasmal damage from compression or vasculitic cerebral infarction.12 Sotelo et al.13 noted that 28% of their 753 cysticercal patients had papilledema, with 10% having decreased vision. Similarly, Takayanagui and Odashima14 reported obstructive hydrocephalus with progressive intracranial hypertension in 50% to 60% of cases with racemose neurocysticercosis. However, none of the reports mentions visual loss with papilledema as the presenting symptom. The treatment of neurocysticercosis is controversial, consisting of cysticidal drugs, steroids, ventriculoperitoneal shunt, and surgical excision of the cysts. The surgical intervention is reserved for those exhibiting compression of brain and cranial nerves, presence of raised intracranial hypertension with or without obstructive hydrocephalus. Prompt diagnosis is essential for treatment in cases of neurocysticercosis, mainly in the intraventricular or subarachnoid-cisternal racemose form because they present clinically in a more aggressive manner as compared with the parenchymal form.15 Racemose neurocysticercosis, although less common, is a serious variety of neurocysticercosis resulting in obstructive hydrocephalus. We present a case of a 22-year-old male with total visual loss in the right eye and visual field loss in the left eye after chronic papilledema secondary to racemose cysts in the subarachnoid-cisternal spaces causing hydrocephalus. Early recognition and surgical intervention can

help in preservation of vision. Ophthalmologists must be aware of this entity as a differential diagnosis of intracranial space-occupying lesions mainly in endemic areas.

Familial exudative vitreoretinopathy mimicking macular telangiectasia type 1

were unremarkable. Fundus examination of the right eye revealed several aneurysmal dilatations temporal to the macula, together with a small area of adjacent fibrosis (Fig. 1). Clinical examination of the left eye was unremarkable. Fundus fluorescein angiography revealed slow filling of the aneurysms with late faint leakage. Furthermore, there was evidence of avascularity of the temporal

A 21-year-old asymptomatic white male in good health was referred by his optometrist for evaluation of a right fundus lesion. His visual acuity was 20/20 OU, and his anterior segment examination and intraocular pressures

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Jyoti Matalia, Hemant Anaspure, Nirupama Kasturi, Bhujang K. Shetty Pediatric Ophthalmology and Strabismology Services, Anekal Taluk, Bangalore, India. Correspondence to: Jyoti Matalia, DNB: [email protected] REFERENCES 1. Kim SW, Kim MK, Oh SM, Park SH. Racemose cysticercosis in the cerebellar hemisphere. J Korean Neurosurg Soc. 2010;48:59-61. 2. Sawhney IM, Singh G, Lekhra OP, Mathuriya SN, Parihar PS, Prabhakar S. Uncommon presentations of neurocysticercosis. J Neurol Sci. 1998;154:94-100. 3. Pittella JE. Neurocysticercosis. Brain Pathol. 1997;7:681-93. 4. Kimura-Hayama ET, Higuera JA, Corona-Cedillo R, et al. Neurocysticercosis: radiologic-pathologic correlation. Radiographics. 2010;30: 1705-19. 5. Ghose D, Dubey TN, Prabhakar S. Brain parenchymal, subarachnoid racemose, and intraventricular cysticercosis in an Indian man. Postgrad Med J. 1999;75:164-7. 6. Mittal P, Mittal G. Intraventricular and subarachnoid racemose cysticercosis. Trop Parasitol. 2011;1:111-2. 7. Arora A, Puri SK, Upreti L. Intracranial Neurocysticercosis. In: Arora A, Puri SK, Upreti L (Eds). Brain Imaging: Case Review Series. New Delhi: Jaypee Brothers Medical Publishers; 2011;80. 8. Martinez HR, Rangel-Guerra R, Elizondo G, et al. MR imaging in neurocysticercosis: a study of 56 cases. AJNR Am J Neuroradiol. 1989;10:1011-9. 9. Bannur U, Rajshekhar V. Cisternal cysticercosis: a diagnostic problem—a short case report. Neurol India. 2001;49:206-8. 10. Mathews M, Pare L, Hasso A. Intraventricular crytococcal cysts masquerading as racemose neurocysticercosis. Surg Neurol. 2007;67:647-9. 11. Carabin H, Ndimubanzi PC, Budke CM, et al. Clinical manifestations associated with neurocysticercosis: a systematic review. PLoS Negl Trop Dis. 2011;5:e1152. 12. Chang GY, Keane JR. Visual loss in cysticercosis: analysis of 23 patients. Neurology. 2001;57:545-8. 13. Sotelo J, Guerrero V, Rubio F. Neurocysticercosis: a new classification based on active and inactive forms. A study of 753 cases. Arch Intern Med. 1985;145:442-5. 14. Takayanagui OM, Odashima NS. Clinical aspects of neurocysticercosis. Parasitol Int. 2006;55:S111-5. 15. Sinha S, Sharma BS. Intraventricular neurocysticercosis: a review of current status and management issues. Br J Neurosurg. 2012;26: 305-9. Can J Ophthalmol 2014;49:e26–e28 0008-4182/14/$-see front matter & 2014 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.11.002

CAN J OPHTHALMOL — VOL. 49, NO. 1, FEBRUARY 2014

Correspondence

Fig. 1 — Colour fundus photograph demonstrating aneurysmal dilatation and associated fibrosis in the right temporal fundus.

Fig. 2 — The venous phase of the fundus fluorescein angiograph of the same patient revealing irregular filling of the aneurysmal dilatations with avascularity of the temporal fundus.

periphery beyond the aneurysmal vessels (Fig. 2). This, combined with a positive family history of familial exudative vitreoretinopathy (FEVR; diagnosed in the patient’s half sister), suggested a diagnosis of FEVR simulating macular telangiectasia type 1 (MacTel 1).

FEVR is a phenotypically and genetically heterogenous vitreoretinopathy first described by Criswick and Schepens in 1969.1 The condition is characterized by failure of the peripheral retina to vascularize, and the fundus abnormalities found in FEVR bear some resemblance to those encountered in retinopathy of prematurity. Although the most commonly identifiable inheritance pattern is autosomal dominant, X-linked and autosomal recessive forms of FEVR also occur. Autosomal inheritance has been linked to 4 genes: the frizzled4 gene (FZD4),2,3 the lowdensity lipoprotein receptor–related protein 5 gene (LRP5),4 the tetraspanin 12 gene (TSPAN12),5 and the zinc finger protein 408 gene (ZNF408),6 whereas X-linked recessive FEVR has been linked to the Norrie disease pseudoglioma gene (NDP).7 The spectrum of clinical presentations in FEVR ranges from subclinical disease, in which subtle peripheral retinal vascular anomalies can only be detected by fundus fluorescein angiography, to severe disease in which peripheral retinal ischemia leads to fibrovascular proliferation and tractional retinal detachment. Those with milder forms of FEVR may express vascular anomalies that mimic those found in MacTel 1. This latter disease occurs predominantly in males and is characterized by aneurysmal dilatation of the retinal vessels, which is typically unilateral and located in the temporal fundus. Patients with milder variants of the MacTel 1 spectrum may remain asymptomatic throughout life, and such cases are usually detected incidentally, whereas severe forms of the condition (Coats disease) may result in blindness in the first decade of life, typically from exudative complications. Although the precise cause of MacTel 1 is unknown, it has been suggested that it may in some cases result from somatic mutations to the NDP gene on Xp11.3,8 an observation that could account for both the unilateral nature of the condition and its male preponderance. The common feature of the genetic defects identified in FEVR and MacTel 1 is that they all affect genes whose products either directly participate in (FZD4, LRP5, TSPAN12, NDP), or possibly inirectly affect (ZNF408), the Norrin/β-catenin signaling pathway, which is believed to be crucial for normal retinal angiogenesis (see Table 1). Because of common clinical features, distinguishing between mild FEVR with aneurysmal dilatations and MacTel 1 may be difficult, even for seasoned clinicians.9 However, fundus fluorescein angiography differentiates the two: retinal nonperfusion associated with MacTel

Table 1—Summary of the genes implicated in the pathogenesis of familial exudative vitreoretinopathy Gene Frizzled 4 (FZD4) gene Lipoprotein receptor–related protein (LRP5) gene Tetraspanin 12 (TSPAN12) gene Zinc finger protein 408 (ZNF408) gene Norrie disease protein (NDP) gene

Location

Function of Gene Product

11q14.23 11q13.43 7q31.313 11p11.23 Xp11.4-p11.33

Heptahelical cellular membrane receptor/coreceptor molecule (with LRP5)6 Homodimeric transmembrane receptor/coreceptor molecule (with FZD4)6 Transmembrane signal regulating molecule: regulates multimerization of FZD46 DNA-binding regulatory molecule6 Secreted protein that acts as a ligand for FZD46

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Correspondence 1 occurs in localized areas adjacent to clinically observable vascular abnormalities, whereas those with FEVR demonstrate avascularity of the retinal periphery, which is most marked temporally. It should be noted that distinguishing between mild FEVR and asymptomatic MacTel 1 is not simply an academic exercise: because of both its potentially sight-threatening nature and its most common mode of inheritance, those with FEVR should be given appropriate genetic counseling, and screening should be offered to their offspring and other direct relatives. Matthew P. Simunovic, David A.L. Maberley University of British Columbia, Eye Care Centre/VGH, Vancouver, B.C. Correspondence to: Matthew P. Simunovic, MB: [email protected]

3. Gene cards—the human gene compendium. www.genecards.org. Accessed October 19, 2013. 4. Toomes C, Bottomley HM, Jackson RM, et al. Mutations in LRP5 or FZD4 underlie the common familial exudative vitreoretinopathy locus on chromosome 11q. Am J Hum Genet. 2004;74:721-30. 5. Nikopoulos K, Gilissen C, Hoischen A, et al. Next-generation sequencing of a 40 Mb linkage interval reveals TSPAN12 mutations in patients with familial exudative vitreoretinopathy. Am J Hum Genet. 2010;86:240-7. 6. Collin RW, Nikopoulos K, Dona M, et al. ZNF408 is mutated in familial exudative vitreoretinopathy and is crucial for the development of zebrafish retinal vasculature. Proc Natl Acad Sci U S A. 2013;110: 9856-61. 7. Chen ZY, Battinelli EM, Fielder A, et al. A mutation in the Norrie disease gene (NDP) associated with X-linked familial exudative vitreoretinopathy. Nat Genet. 1993;5:180-3. 8. Black GC, Perveen R, Bonshek R, et al. Coats’ disease of the retina (unilateral retinal telangiectasis) caused by somatic mutation in the NDP gene: a role for norrin in retinal angiogenesis. Hum Mol Genet. 1999;8:2031-5. 9. Laird PW, Hubbard GB. August 2012 cover photo is not Coats’ disease. Ophthalmology. 2013;120:e51-2.

REFERENCES 1. Criswick VG, Schepens CL. Familial exudative vitreoretinopathy. Am J Ophthalmol. 1969;68:578-94. 2. Robitaille J, MacDonald ML, Kaykas A, et al. Mutant frizzled-4 disrupts retinal angiogenesis in familial exudative vitreoretinopathy. Nat Genet. 2002;32:326-30.

Nasal chondromesenchymal hamartoma with incomitant esotropia in an infant: a case report Nasal chondromesenchymal hamartoma (NCMH) is a rare benign tumour that usually occurs in infants. Patients with NCMH may have ophthalmic manifestations without nasal symptoms, secondary to orbital tumour involvement.1 The authors report on a case of NCMH with incomitant esotropia in a 9-month-old female infant. A 9-month-old female infant presented at our ophthalmic clinic with inward deviation of the right eye. The parents informed us that she had exhibited marked limitation of abduction in the right eye since birth. She was delivered after an uncomplicated full-term pregnancy at a birth weight of 2.9 kg. During the course of pregnancy, there was no history of any radiation exposure or drug intake. Upon subsequent ophthalmologic consultation, no afferent pupillary defect was observed in either eye. Findings of alternate prism cover testing indicated 10 prism diopters of esotropia at distance in the primary position. The patient showed marked limitation (–4) on abduction and mild limitation (–1) on adduction in the right eye (Fig. 1A). On attempted adduction, no other diagnostic signs of Duane retraction syndrome (DRS), such as globe retraction or downshoots or upshoots, were observed in the right eye, and no protrusion of the right eyeball was evident (Fig. 1B). Furthermore, there was no abduction of the right eye on the doll’s head manoeuvre. However, forced duction

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Can J Ophthalmol 2014;49:e28–e30 0008-4182/14/$-see front matter & 2014 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.11.006

testing could not be used to confirm restrictive strabismus because of poor cooperation in an outpatient clinic. Anterior and posterior segments of both eyes were normal. Based on clinical evidence, DRS, restrictive strabismus, or sixth nerve palsy were initially suspected. Thus, magnetic resonance imaging (MRI) and thin-section, gradient-echo MRI were performed in an axial plane at the level of the brainstem to identify of the presence of abducens nerves and other causes, such as a mass lesion. Both abducens nerves were observed in thin-section gradient-echo MRI (Fig. 1C), but a soft tissue mass was detected in the nasal cavity and maxillary sinus (Fig. 1C); also, subsequent computerized tomography (CT) visualized a heterogeneous multicystic mass in the right nasal cavity and right maxillary sinus, and bone defects in the inferomedial orbital wall and cribriform plate (Fig. 1D). Fluorine-18 fluorodeoxyglucose positron emission tomography-CT was also performed, and it showed increased tracer uptake by the mass, but no evidence of metastasis (Fig. 1E). Nasal endoscopy was performed, and a huge bulge covered with healthy mucosa was observed in the nasal cavity. Multiple punch biopsies of mucosa and mass were taken (Fig. 2A). Microscopic examination of the tumour showed chondromyxoid and hyalinized nodules surrounded by a bland spindle cell component (Fig. 2B). Immunohistochemical staining showed immunoreactivity for smooth muscle actin in spindle cells (Fig. 2C). S100 protein–positive stromal cells were focally observed (Fig. 2D).

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