|Year : 2007 | Volume
| Issue : 1 | Page : 28-31
Extensive plexiform neurofibroma in a patient with neurofibromatosis type I
Ahmad H Batal, Bassem G Hassanien
Pediatric and Strabismus Division, Department of Ophthalmology, Magrabi Eye and Ear Hospital, Jeddah, Saudi Arabia
|Date of Web Publication||11-Nov-2009|
Ahmad H Batal
Magrabi Eye and Ear Hospital, Khozam Street, Kilo 3, Jeddah 21462
Source of Support: None, Conflict of Interest: None
| Abstract|| |
We describe the case of 2-year-old boy with neurofibromatosis type I who developed an extensive diffuse plexiform neurofibroma of the right orbit. A paraspinal mass that involved the right parotid and parapharyngeal space with extension through the foramen ovale into the right cavernous sinus was also detected.
Keywords: neurofibromatosis, plexiform neurofibroma, orbital tumor, proptosis
|How to cite this article:|
Batal AH, Hassanien BG. Extensive plexiform neurofibroma in a patient with neurofibromatosis type I. Middle East Afr J Ophthalmol 2007;14:28-31
|How to cite this URL:|
Batal AH, Hassanien BG. Extensive plexiform neurofibroma in a patient with neurofibromatosis type I. Middle East Afr J Ophthalmol [serial online] 2007 [cited 2020 Oct 23];14:28-31. Available from: http://www.meajo.org/text.asp?2007/14/1/28/57688
In 1882, von Recklinghausen first described neurofibromatosis type I (NF-1), or peripheral neurofibromatosis  NF-1, an autosomal dominant disorder, is the most common single gene disorder that affects the nervous system, occurring in approximately 1 in 3000 people. The pericentromeric region of the long arm of chromosome 17 is the location of this gene. 
Neurofibromatosis type I, which presents in childhood, is characterized by multiple pigmented macules (cafι-au-lait spots), intertriginous freckling, iris hamartomas (Lisch nodules), and multiple skin neurofibromas.  Four types of neurofibromas are recognized. The first type of neurofibroma is characterized by discrete, blue-tinged cutaneous neurofibromas in the epidermis and dermis. The second type of neurofibroma is distinguished by subcutaneous neurofibromas occurring deep in the dermis, along the course of peripheral nerves. Both of these types of nodules feel firm and rounded, and the skin moves over them. The third type of neurofibroma consists of localized nodular plexiform neurofibromas that interdigitate in normal tissues. The fourth type of neurofibroma is characterized by diffuse plexiform neurofibromas that infiltrate widely and diffusely into surrounding tissues. Classically, they feel like a "bag of worms" when palpated. Localized and diffuse plexiform neurofibromas are the most active, and give rise to cosmetic and visual problems within the orbit. 
Orbital involvement by plexiform neurofibromas may give rise to early complications as the tumor tends to grow rapidly in the first 3 years of life. They can be associated with 4 types of orbital bone changes, namely, expansion of the orbit, enlargement of the orbital rim, bone erosion, and enlargement of the cranial foramina.  Growth may be directed backward, eroding the orbital walls into the middle cranial fossa, and producing enophthalmos or exophthalmos. They may also grow forward into the face, giving rise to disfigurement. 
Sphenoid wing dysplasia may be present in NF-1, but it is not known whether it is dysplastic or secondary to plexiform neurofibroma.  It is of clinical importance because it may result in herniation of the temporal lobe into the orbit. Accordingly, the pulsation of the temporal lobe may be transmitted through the globe, thus being visible externally as pulsatile exophthalmos. 
We describe a case in which there was extensive diffuse plexiform neurofibroma of the right orbit.
| Case Report|| |
A 2-year-old boy presented with a history of proptosis of the right eye since birth [Figure 1]. There was no family history of neurofibromatosis. An excision of a mass lesion in the right upper eyelid had been previously performed at another institution.
Physical examination revealed many (> 6) cafι-au-lait spots measuring more than 5 mm in greatest diameter [Figure 2] and 1 measuring more than 15 cm on the left thigh [Figure 3]. Left axillary freckling was also present.
On ocular examination, the patient could fix and follow with both eyes. There was axial proptosis and mechanical ptosis of the right eye. A surgical scar was present in the right upper eyelid from a previous excisional biopsy. Ocular motility was full. Pupillary reflexes were normal. On slit-lamp examination, a stromal opacity in the right cornea and a single Lisch nodule in the iris of the left eye were detected. Fundus examination was normal in both eyes.
Magnetic resonance imaging (MRI) of the brain, orbits, neck, and upper chest showed a large paraspinal soft-tissue mass extending along the upper 3 dorsal vertebrae. In the neck, the mass involved the right parotid and the right parapharyngeal space, extending into the foramen ovale to the right cavernous sinus [Figure 4]. Proptosis associated with a soft-tissue mass, and thickening of the extraocular muscles and the right lacrimal gland were present in the right orbit [Figure 5]. Sinusitis involving the ethmoidal air cells and the maxillary sinuses, and effusion in the right middle ear were also detected. Magnetic resonance angiography (MRA) showed compression of the right internal carotid artery by the cavernous sinus component of this lesion. Computed tomography (CT) of the orbit revealed expansion of the right orbit and widening of the superior orbital fissure [Figure 6]. A technetium-99 m-labeled red blood cell (Tc-99 m RBC) scan was performed, which showed no clear pooling of the isotope within the lesion.
The patient was operated upon by a plastic reconstructive surgeon in an attempt to debulk the neurofibroma involving the right upper lid and orbit. Histopathological examination of the mass confirmed the diagnosis of diffuse, plexiform neurofibroma.
| Discussion|| |
The diagnostic criteria for neurofibromatosis were outlined in the conference statement of the National Institutes of Health.  The criteria of diagnosis of NF-1 include 2 or more of the following: (1) 6 or more cafι-au-lait macules larger than 5 mm in greatest diameter in prepubescent children and larger than 15 mm in greatest diameter in postpubescent adults; (2) 2 or more neurofibromas of any type or 1 plexiform neurofibroma; (3) freckling in the axillary or inguinal region; (4) optic glioma; (5) 2 or more Lisch nodules (iris hamartomas); (6) a distinctive osseous lesion, such as sphenoid dysplasia or thinning of the long bone cortex with or without pseudoarthrosis; and (7) a first-degree relative (parent, sibling, or offspring) with NF-1 in accordance with the abovementioned criteria.
Three diagnostic criteria (cafι-au-lait spots, plexiform neurofibroma, and axillary freckles) were present in our case. The plexiform lesions were extensive and involved the extraocular muscles, vessels, optic nerve, and lacrimal gland, leading to marked expansion of the right orbit and proptosis. The lesion extended through the superior orbital fissure to the right cavernous sinus and through the cranial nerve foramina into to the right parapharyngeal space, the right parotid, and the right paraspinal space.
Neurofibromas are not radiosensitive and are difficult to treat surgically.  In our case, the plexiform neurofibroma was sight-threatening and had induced severe cosmetic disfigurement. The patient had previously been operated on elsewhere by a plastic reconstructive surgeon in an attempt to debulk the orbital mass, but residual elements deep within the orbit continued to grow afterward. After admission to our facility, extensive orbital resection of the tumor was performed. Although these tumors tend to bleed profusely at surgery, this did not occur in our case. The lack of pooling of radioactive isotope within the lesion during the Tc-99 m RBC scan suggested that the tumor was not of a hemangiomatous nature.
In conclusion, the ophthalmologist may have a pivotal role in making the diagnosis of NF-1, by correctly identifying Lisch nodules, orbital plexiform neurofibromas, sphenoidal wing defects, and optic nerve glioma. Sometimes sight- or life-threatening manifestations of NF-1 may precede other systemic findings. It is, therefore, essential for pediatric ophthalmologists to be aware of the ocular features of NF-1, and refer early and appropriately for neuroradiological or other relevant investigations. When neurofibromas are extensive, they cannot usually be completely excised. As a consequence, multiple subtotal resections may be required, and recurrence after partial removal is typical. Orbital exenteration in an eye with poor vision and marked cosmetic disfigurement may be necessary. 
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]