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Show Journal of CliniCilI Neuro-ophthalmology 13(3): 171-174. 1993. '9 1993 Raven Press, Ltd .. New York Severe Enophthalmos Following Intracranial Decompression in a Von Recklinghausen Patient Barrett G. Haik, M.D. and Michael Pohlod, M.D. A patient with neurofibromatosis type I and absence of the sphenoid wing developed proptosis of the right eye secondary to expansion of the intracranial contents from an intracranial astrocytoma associated with cerebral edema and hydrocephalus. Marked enophthalmos developed following excision of the intracranial tumor and placement of a ventriculoperitoneal shunt. Absence of the sphenoid bone limited the orbit's ability to halt posterior refraction of the orbital contents when the intracranial volume decreased. Key Words: Neurofibromatosis type I-von Recl<linghausen's disease-Enophthalmos-Sphenoid wing dysplasia. From the Department of Ophthalmology, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A. This study was supported in part by unrestricted grants from the St. Giles Foundation, New York, and Research to Prevent Blindness, Inc., New York. Address correspondence and reprint requests to Dr. Barrett G. Haik, Tulane University School of Medicine, Department of Ophthalmology, 1430 Tulane Avenue, New Orleans, LA 701122699, U.s.A. 171 Von Recklinghausen's neurofibromatosis is a highly variable, autosomal dominant disease with an incidence of approximately 30 per 100,000 (1). The gene for neurofibromatosis type I has been localized near the centromere of chromosome 17 (2). Its clinical manifestations are thought to be attributed to primary dysontogenesis of the primitive neuroectoderm and its neural crest derivatives (3). Neurofibromatosis type I may become apparent in many systems. Dermatologically, cafe au lait spots and cutaneous neurofibromas are frequent findings. Skeletal signs include scoliosis, sphenOid wing dysplasia, bony distortion, and local cystic and erosive changes (4). Central nervous system indications consist of an increased incidence of astrocytomas, meningiomas, schwannomas, and ependymomas. Furthermore, hydrocephalus secondary to aqueductal stenosis has been associated with neurofibromatosis (5,6). Many ophthalmic manifestations may occur in the von Recklinghausen patient. Lisch nodules are virtually pathognomonic, and Huson et a1. (7) found these iris hamartomas to be present in all of his neurofibromatosis type I patients over 16 years of age. Other findings include choroidal harmartomas (8), plexiform neurofibromas, and optic nerve gliomas. Exophthalmos and enophthalmos, potential sequelae, are associated with orbital tumors and/or sphenoid wing dysplasia. The following case describes an exophthalmic neurofibromatosis type I patient who developed severe enophthalmos upon removal of an intracranial astrocytoma. CASE REPORT A 20-year-old white female with neurofibromatosis type I was referred to our institution for cosmetic correction of a severe enophthalmic right 172 B. G. HAIK AND M. POHLOD FIG. 1. Early generation axial computed tomog ram reveals the right eye to be displaced anteriorly by herniation of intracranial contents through the region of absent bone. The intracranial and orbital contents are separated only by dura. globe. The patient's past medical history bears significance because as a 9-year-old, she presented to another institution with a 6-mm nonpulsatile proptosis. Further examination demonstrated severe papilledema 00 and mild papilledema OS. A computed tomographic (CT) scan revealed cerebral edema, marked hydrocephalus, absence of the right sphenoid wing, and right-sided proptosis (Fig. 1). On lower sections, an infratentorial avascular mass was found in approximation with the right posterior fossa. Progressive truncal ataxia with mild bilateral dysmetria developed 2 weeks following admission. Subsequently, the patient received a ventriculoperitoneal shunt and craniotomy for tumor excision. The tumor proved to be an astrocytoma grade II-III. She recovered with no FIG. 3. Contrast enhanced axial computed tomogram depicting absence of the right sphenoid and secondary enophthalmos of the globe. complications except for the previously mentioned globe displacement. At our institution, physical exam revealed a medially displaced, 12-mm enophthalmic right globe (Fig. 2). Severe motility restriction was noted in all directions with positive forced duction tests for generalized restriction. She had a visual acuity of 20/100 00 and 20/30 as. Other notable findings included multiple cafe au lait spots and a family history of neurofibromatosis. A CT scan showed enophthalmos 00, right sphenoid wing absence, and no evidence of residual tumor (Fig. 3). Threedimensional computed tomographic analysis clearly depicted the full extent of the bony defect (Fig. 4). Orbital reconstruction was not elected due to the extensive orbital contracture and extraocular muscle sclerosis. Thus, the patient was ultimately managed with cautery of Bowman's membrane, a FIG. 2. Patient with severe right-sided enophthalmos and immobile globe. I Clill Neuro-ophthllimoi. Vol. 13, No.3, 1993 ENOPHTHALMOS AFTER INTRACRANIAL DECOMPRESSION 173 right conjunctival flap, and a flush-fitting cosmetic shell. For 3 months, the patient had an acceptable cosmetic appearance, however, she developed orbital pain, which was only alleviated by thinning the prosthesis. With the smaller prosthesis in place, enophthalmos and sulcus deformity were more noticeable (Fig. 5). Subsequently, the patient has been comfortable and stable for 4 years. DISCUSSION Von Recklinghausen's disease encompasses a variety of sequelae involving tissue of neural crest origin. This case demonstrates how globe position can depend on a number of associated factors. Sphenoid wing dysplasia has been described in up to 7 to 12.8 percent of patients with neurofibromatosis (9,10). Right sphenoid wing absence in our patients plays a crucial role in the initial anterior and succeeding posterior globe displacement. Crowe et al. (1) found an increased prevalence of both supra- and infratentorial neoplasms, including astrocytomas, in neurofibromatosis patients as compared to the rest of the population. In this case, the mass effect and obstructive hydrocephalus created by the astrocytoma resulted in increased intracranial pressure. The sphenoid wing absence allowed this pressure to be directly transmitted into the orbit, resulting in the initial exophthalmic presentation. Senveli et al. (5) noted that nontumoral hydrocephalus secondary to aqueductal glial cell proliferation has also been associated with neurofibromatosis type I. However, it is impossible to determine if this mechanism contributed to our patient's hydrocephalus. Unilateral enophthalmos, usually seen as a com- FIG. 4. Anterior view (A) and posterior view (B) of three-dimensional computed tomographic study revealing details of the bony defect. J Clin Neuro-ophthalmol. Vol. 13, No.3, 1993 174 B. G. HAIK AND M. POHLOD FIG. 5. The patient's clinical appearance is slightly improved with a cosmetic shell placed anterior to the enophthalmic globe. plication of an orbital fracture, may result from other causes such as microphthalmos, orbital fibrosis, and sclerosing orbital tumors. In our case, a patient with sphenoid wing dysplasia developed a 12-mm enophthalmos after intracranial decompression. The sphenoid defect and extraocular muscle sclerosis accounted for the posterior globe position. Savino et al. (11) demonstrated a less dense and smaller than normal retro-orbital fat pad abnormality in an enophthalmic neurofibromatosis type I patient with sphenoid dysplasia. We, however, could not determine if this mechanism had a part in our patient's enophthalmos. Prompt orbital reconstruction following intracranial decompression in this patient with sphenoid dysplasia is controversial, but it may have reduced her cosmetic and functional defects by blocking posterior retraction of the globe. Craniofacial surgery in order to reconstruct the bony orbit has been utilized in patients with neurofibromatosis and sphenoid dysplasia (12,13). Despite generally disappointing surgical results, some physicians and patients felt that the procedures were worthwhile. Forming a structural barrier between the brain and orbit typically involves gaining access via craniotomy and significant manipulation of both the orbital and intracranial contents. Bone grafts or wire mesh are most often utilized to create a mechanical boundary. Patients have often required staged procedures to achieve the desired result. Reported complications include variable resorbtion of bone grafts, hemorrhage, and corneal exposure. Potential complications of such extensive surgery include meningitis, cerebral trauma, and optic nerve damage. Therefore, the risks and benefits of such surgery must be carefully evaluated. The use of a cosmetic shell placed anterior to the / Cllll Ncuro-0l'hthalmol, Vol. 13. No.3, 1993 enophthalmic globe in our patient resulted in a reasonable cosmetic appearance initially; however, chronic orbital irritation occurred. Reducing the size of the prosthesis relieved the discomfort, but resulted in residual enophthalmos and a deep superior sulcus. In summary, this case is of interest because it demonstrates a unique interplay of neurofibromatosis stigmata on globe position, and the difficulties associated with clinical management. 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